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Best Selling Genuine Geo Oxygen Sensors

  • We Stock the following top leading brands, including ACDelco, Denso, Delphi, Bosch
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We stock Oxygen Sensor parts for most Geo models, including Metro, Prizm, Spectrum, Storm, Tracker.

ACDelco
1989 Geo Metro Oxygen Sensor ACDelco

P311-09746F9    New

Qty:
$19.23
ACDelco Oxygen Sensor
  • This Original Equipment Manufacturer part is the same part that was made & installed by the car manufacturer at the factory where the car was produced.
Brand: ACDelco
This Product is Eligible for Free Ground Shipping
Additional Fitment Information:
Vehicle
1989 - Geo Metro
ACDelco
1989 Geo Metro Oxygen Sensor ACDelco

P311-09746F9    New

Qty:
$23.34
ACDelco Oxygen Sensor
Brand: ACDelco
This Product is Eligible for Free Ground Shipping
Additional Fitment Information:
Vehicle
1989 - Geo Metro
Denso
1995 Geo Prizm Oxygen Sensor - Downstream 4 Cyl 1.8L Denso

P311-281654D    New

Qty:
$56.82
Denso Oxygen Sensor  Downstream
  • 4 Wire, Direct Fit, Heated, Wire Length: 14.17
  • OE Style
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1995 - Geo Prizm L 1788 110 Downstream
Denso
1995 Geo Prizm Oxygen Sensor - Downstream 4 Cyl 1.8L Denso

P311-281654D    New

Qty:
$56.82
Denso Oxygen Sensor  Downstream
  • 4 Wire, Direct Fit, Heated, Wire Length: 14.17
  • DENSO is the O.E. Manufacturer / Oxygen Sensor
  • OE Style
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1995 - Geo Prizm L 1788 110 Downstream
Denso
1994 Geo Metro Oxygen Sensor - Upstream 3 Cyl 1.0L Denso

P311-3D20ED7    New

Qty:
$36.72
Denso Oxygen Sensor  Upstream
  • 4 Wire, Universal, Heated, Wire Length: 11.77
  • Universal
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1994 - Geo Metro L 993 61 Upstream
Denso
1996 Geo Metro Oxygen Sensor - Downstream 4 Cyl 1.3L Denso

P311-3D20ED7    New

Qty:
$36.72
Denso Oxygen Sensor  Downstream
  • 4 Wire, Universal, Heated, Wire Length: 11.77
  • Universal
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1996 - Geo Metro L 1295 79 Downstream
Denso
1995 Geo Metro Oxygen Sensor - Upstream 4 Cyl 1.3L Denso

P311-3D20ED7    New

Qty:
$36.72
Denso Oxygen Sensor  Upstream
  • 4 Wire, Universal, Heated, Wire Length: 11.77
  • O.E. Quality Universal Replacement Sensor
  • Universal
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1995 - Geo Metro L 1295 79 Upstream
Denso
1996 Geo Metro Oxygen Sensor - Downstream 4 Cyl 1.3L Denso

P311-3D20ED7    New

Qty:
$36.72
Denso Oxygen Sensor  Downstream
  • 4 Wire, Universal, Heated, Wire Length: 11.77
  • O.E. Quality Universal Replacement Sensor
  • Universal
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1996 - Geo Metro L 1295 79 Downstream
Denso
1994 Geo Metro Oxygen Sensor - Upstream 3 Cyl 1.0L Denso

P311-3D20ED7    New

Qty:
$36.72
Denso Oxygen Sensor  Upstream
  • 4 Wire, Universal, Heated, Wire Length: 11.77
  • Calif. O.E. Quality Universal Replacement Sensor
  • Universal
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1994 - Geo Metro L 993 61 Upstream
Denso
1994 Geo Metro Oxygen Sensor - Upstream 3 Cyl 1.0L Denso

P311-3D20ED7    New

Qty:
$36.72
Denso Oxygen Sensor  Upstream
  • 4 Wire, Universal, Heated, Wire Length: 11.77
  • O.E. Quality Universal Replacement Sensor Calif.
  • Universal
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1994 - Geo Metro L 993 61 Upstream
Denso
1989 Geo Metro Oxygen Sensor - Upstream 3 Cyl 1.0L Denso

P311-2D6878D    New

Qty:
$13.18
Denso Oxygen Sensor  Upstream
  • 1 Wire, Direct Fit, Unheated, Wire Length: 14.57
  • OE Style
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1989 - Geo Metro L 993 61 Upstream
Denso
1989 Geo Metro Oxygen Sensor - Upstream 3 Cyl 1.0L Denso

P311-2D6878D    New

Qty:
$13.18
Denso Oxygen Sensor  Upstream
  • 1 Wire, Direct Fit, Unheated, Wire Length: 14.57
  • O.E. Quality Replacement Sensor
  • OE Style
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1989 - Geo Metro L 993 61 Upstream
Denso
1994 Geo Metro Oxygen Sensor - Upstream 3 Cyl 1.0L Denso

P311-2D6878D    New

Qty:
$13.18
Denso Oxygen Sensor  Upstream
  • 1 Wire, Direct Fit, Unheated, Wire Length: 14.57
  • Excludes Calif. O.E. Quality Replacement Sensor
  • OE Style
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1994 - Geo Metro L 993 61 Upstream
Denso
1994 Geo Metro Oxygen Sensor - Upstream 3 Cyl 1.0L Denso

P311-2D6878D    New

Qty:
$13.18
Denso Oxygen Sensor  Upstream
  • 1 Wire, Direct Fit, Unheated, Wire Length: 14.57
  • O.E. Quality Replacement Sensor Excludes Calif.
  • OE Style
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1994 - Geo Metro L 993 61 Upstream
Denso
1990 Geo Storm Oxygen Sensor - Upstream 4 Cyl 1.6L Denso

P311-2D6878D    New

Qty:
$13.18
Denso Oxygen Sensor  Upstream
  • 1 Wire, Direct Fit, Unheated, Wire Length: 14.57
  • O.E. Quality Replacement Sensor VIN 6
  • OE Style
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Engine VIN Position
1990 - Geo Storm L 1588 98 6 Upstream
Delphi
1989 Geo Metro Oxygen Sensor - Upstream Delphi

P311-4153959    New

Qty:
$14.15
Delphi Oxygen Sensor  Upstream
  • Oxygen Sensor
  • Wrench Size: 7/8 in.
  • Product Attributes:
    • Connector Type: Round-1 Pin
    • Inspection Interval: 100,000 Miles
    • Location: Upstream
    • Number of Wires: 1
    • OE Type/Exact Fit: Oe Type / Exact Fit
    • Overall Length: 320 Mm
    • Thread: 18 X 1.5 Mm
    • Type/Series: Unheated
    • Wrench Size: 7/8 In.
  • OE connectors and wire lengths within 3 inches of OE specifications; Unique sensor coatings to resist contamination; Long lasting reliable operation.
Brand: Delphi
Additional Fitment Information:
Vehicle Position
1989 - Geo Metro Upstream
Delphi
1994 Geo Metro Oxygen Sensor - Upstream 3 Cyl 1.0L Delphi

P311-4153959    New

Qty:
$14.15
Delphi Oxygen Sensor  Upstream
  • Oxygen Sensor
  • Wrench Size: 7/8 in. Exc California
  • Product Attributes:
    • Connector Type: Round-1 Pin
    • Inspection Interval: 100,000 Miles
    • Location: Upstream
    • Number of Wires: 1
    • OE Type/Exact Fit: Oe Type / Exact Fit
    • Overall Length: 320 Mm
    • Thread: 18 X 1.5 Mm
    • Type/Series: Unheated
    • Wrench Size: 7/8 In.
  • OE connectors and wire lengths within 3 inches of OE specifications; Unique sensor coatings to resist contamination; Long lasting reliable operation.
Brand: Delphi
Additional Fitment Information:
Vehicle Block CC CID Position
1994 - Geo Metro L 993 61 Upstream
Denso
1995 Geo Prizm Oxygen Sensor - Upstream 4 Cyl 1.8L Denso

P311-1E807C9    New

Qty:
$37.17
Denso Oxygen Sensor  Upstream
  • 2 Wire, Direct Fit, Unheated, Wire Length: 18.82
  • OE Style
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1995 - Geo Prizm L 1788 110 Upstream
Denso
1995 Geo Prizm Oxygen Sensor - Upstream 4 Cyl 1.8L Denso

P311-1E807C9    New

Qty:
$37.17
Denso Oxygen Sensor  Upstream
  • 2 Wire, Direct Fit, Unheated, Wire Length: 18.82
  • DENSO is the O.E. Manufacturer / Oxygen Sensor
  • OE Style
  • DENSO oxygen sensors are manufactured and tested to the strictest OE standards for unparalleled peformance; Each component is precision built for exact replacement, and a first time fit; This innovative line features DENSO's exclusive aluminum oxide trap layer, designed to protect the ceramic element from silicone and lead posining for improved engine performance, greater fuel efficiency, and unparalleled longevity; DENSO gives you the right part and the right fit, the first time.
Brand: Denso
Additional Fitment Information:
Vehicle Block CC CID Position
1995 - Geo Prizm L 1788 110 Upstream
Bosch
1994 Geo Metro Oxygen Sensor - Upstream 3 Cyl 1.0L Bosch

P311-40C6811    New

Qty:
$50.66
Bosch Oxygen Sensor  Upstream
  • OE manufactured part with California Emissions
  • Universal Oxygen Sensor
  • Product Attributes:
    • Automotive Color / Finish: Steel
    • Connector Shape: None
    • Housing Material: Metal
    • Installation Hardware Included: Universal Connector Kit
    • Mounting Type: Threaded
    • Thread Diameter: 18
    • Universal Or Specific Fit: Universal
    • Wire Quantity: 4
Brand: Bosch
Additional Fitment Information:
Vehicle Aspiration Block CC CID Position
1994 - Geo Metro Naturally Aspirated L 993 61 Upstream

Latest Geo Repair and Oxygen Sensor Installation Advice

CarJunky AutoAdvice

wiring an universal oxygen sensor

Showing 2 out of 2 Posts
Question From Guest on wiring an universal oxygen sensor

Could someone please tell me how to wire up my Bosch universal O2 sensor for my 96 Geo Metro??? The part number for the new sensor is: 15733 and it has 4 wires coming out of it...The colors of the wires are 1 black which is supposed to be the signal wire, there are 2 white ones which are supposed to be heater wires, and one grey one which is ground...This is information from the instructions.. What I'm having a problem with is which wires do I connect 'em to??? I have no way of knowing which wires on the vehicle to use for which colors...The colors on the vehicle are: 2 black wires, 1 white wire, and 1 blue wire.... The car is a 96 model Geo Metro 1 liter engine... Any help would be much appreciated.. Thanks..

Response From Double J Top Rated Answer


Here is an electrical diagram...hope it helps...

Heated Oxygen Sensor (HO2S) Circuit Sensor 1

trouble shooting automotive

Showing 2 out of 7 Posts | Show 5 Hidden Posts
Question From Rich G on trouble shooting automotive

1997 Geo Metro
1.3 liter
100,000 miles
Hello, my 97 geo metro keeps shutting down on me. I'll start it up in the morning and it will run fine for 20-30 miles then it will just turn off , I'll pull to the side of the road and try to start it but it won't turn over. I'll wait for a few hours it will start right up and do the same thing over again. I've changed the spark plugs, rotor, and distributor cap. PLEASE if you have any idea what could be causing this problem.... Please help me!!!!

Response From kev2

scan for codes YES even if the CEL is not on.
its FREE at most auto parts stores- post any and all codes

It stalls- will not restart- will headlights, horn, radio anything work?

Response From Rich G Top Rated Answer

I took the car over to the auto zone today and had them check the codes and this is what I found, aaHO2S11 heater condition (heated oxygen sensor bank aa1 sensor 1) Explanation the powertrain control module monitors the oxygen sensor heater. The computer has recognized a failure in this circuit. Probable cause 1. sensor defective 2.poor connection at oxygen sensor. 3. Check circuit -fuse ..... Would HO2 sensor cause the car to stall out and not start until I wait a couple hours
CAN ANY ONE HELP

Response From Discretesignals

Usually no. An O2 heater problem won't cause a intermittent no start. When the car is started it is in open loop.

You need to find out what is missing when it doesn't want to start. Check for spark, fuel pressure, injector activity. Once you know what things are missing, you'll have direction in troubleshooting your issue.

Response From Rich G

No codes are coming up and when it stalls out, it still has power... Radio, lights, ect..
I was told it sounds like the distributor, maybe the ignition control module inside the distributor .

Response From Tom Greenleaf

Sport - you are being asked if the engine cranks but doesn't start. We know now you can listen to the radio for a couple hours till it runs which now means nothing.


Where did you determine it has no codes? Same people who said it sounds like a distributor? Next check should be to see if the screws for the license plate are tight enough,


T

Response From Hammer Time

I'll pull to the side of the road and try to start it but it won't turn over. I'll wait for a few hours it will start right up and do the same thing over again.

Are you saying that the starter is not engaging and rotating the engine or that the starter is working but the engine is not starting?

sudden drop in MPG in 92 Geo Metro?

Showing 2 out of 2 Posts
Question From richard123 on sudden drop in MPG in 92 Geo Metro?

This is a 3 cyl engine. Car has consistently gotten 35-36 mpg. I took it on a longer trip ( about 200 miles) and got 39. The very next tank mpg dropped to 27-28. The air filter is new. The EGR valve is working. It moves on acceleration and also I removed it and verifiied both pressure and vacuum with it removed. I also test the oxygen sensor and it was varying up and down as it should. I can not say whether the speed is normal or not. I don't want to replace anything unnecessarily. I also looked around for loose wires or leaky hoses and found nothing. I want my old mileage back. Just when gas prices dropped a little my cost went up. Car drives perfectly normal. What are likely bets.

Response From Mr.scotty Top Rated Answer

No check engine light right?
Has it had a full maintenance service done in the past 15-25,000 miles?
Have you checked your tire pressure?
Buying gas at a different place?

p0125 (Insufficient Coolant Temperature For Closed Loop Fuel Control)

Showing 2 out of 16 Posts | Show 14 Hidden Posts
Question From completelyhis on p0125 (Insufficient Coolant Temperature For Closed Loop Fuel Control)

1997 Geo Prism, 1.6 liter, 175k miles.

I get a P0125 (Insufficient Coolant Temperature For Closed Loop Fuel Control). I have changed the temperature sensor, thermostat, checked coolant level, repaired the exhaust lead that was @ the doughnut flange, and then replaced the front o2 sensor.

The engine gets to "normal" operating temperature w/in a normal time (a few minutes). It runs great. When I clear the code, it comes back within 10 miles or less after clearing it.

I read this here
link deleted............. not allowed

I know that the drive train for the prism is a toyota drive train, so that conversation is relavent, but I don't see a solution I haven't tried.

Any suggestions?

Thanks,

Ian

Response From DRND

I have good experience with this code with toyota 1nz-fe engine i reset code but it take after 15km - 35km
So.....
You should check your system clearly by using car scanner and look at ECT,O2 B1 S1,O2 B2 S2 sensor's values.some time u will feel O2 B1 S1 value is less than other O2 sensor value.but it's OK because O2 sensor locate at after cat(per-cat).but clearly monitor your O2 B1 sensor's value is less than 0.1mv. the ECM monitor this value in time period and set this code
So i swap O2 B1 and O2 B2 sensor then O2 B1 reading was ok.after i drive 100km but not it take this code

Response From Tom Greenleaf

Sport - this is about THREE years old! Please stick to current threads. Locked for archives and keep spammers out now,

T

Response From Hammer Time

I've never heard such an idiotic response either.

Response From Sidom

I think HT is right and it's going to be a temp sensor problem...... Most of the time with this code you have a stuck open T stat. If this code is setting within 10 minutes during this time of the year, it would have to be a electrical problem.

How's it run? Any black smoke out the back or hard starting????

Response From Hammer Time

You really need a scan tool so you can monitor what temp the computer is seeing and you can then determine if and where the problem is.

Response From completelyhis

i assume that's different than my "auto xray" code reader? Can you recommend a good scan tool?

Response From completelyhis

no smoke, starts great runs solid and strong. replaced Tstat and temp sensor. I replaced the one that's on the thermostat housing, with a two-wire harness connected to it...is that the right one?

electrical problem...could you elaborate?

Ian

Response From Tom Greenleaf

You can OHM test CTS and should show that it changes as engine warms up. I don't have the range but most are fine or do nothing. The plug can be the problem,

T

Response From Hammer Time

I think your wasting your time with those types of tests. The code here is indicating that there is insufficient temp for closed loop. I have had to deal with this code before. This can come down to a matter of just a couple degrees so unless you see the exact digital temp that the computer is seeing, your not going to solve this problem. I had one that continuously failed emission but never set any codes and it turned out to be the calibration of the thermostat. It was only about 5 degrees low but that was enough to prevent it from going into closed loop and in turn made it fail emissions.

Response From completelyhis

I took the car to a guy who has the ability to read the ECM data and it ends up that the computer is reading zero's from the o2 sensor.

i did some research and found these suggestions:

Verify continuity between the ECM and O2 Sensor
Make sure that there is 12 V making it to the O2 sensor
Check the resistance of the sensor (should be between 11 and 17 Ohms).
Are those good things to check? Any other testing I could/should do? I assume it's either bad wiring or a bad ECM. Is that a safe assumption? Where is the ECM on the 97 prism, so I can check continuity between it and the o2 sensor? Is there any reason to check the resistance of the sensor other than confirming if the sensor is good or not?

Thanks,

Ian

Response From completelyhis Top Rated Answer

I looked at the device he had hooked up to it while it was hooked up, i saw the MAF readings and all the other ones updating in real time. the o2 was zero constantly. i trust him.

Following are things I've seen about the Toyota obdII codes as it pertains to this:


  • I think that I remember Toyota mis-defining that code number. It's supposed to refer to the O32 sensor signal or heater or the sensor itself. I think I remember that from somewhere that Toyota mis reads that code.
  • By accident I left coolant temperature sensor disconnected. It generated 2 codes. p0115 and p0125. P0115 is the temperature coolant sensor. P0125 Has to do with not getting into a closed loop circuit. Auto Zone listed the cure for the code (125) as faulty temp. sensor, 2. bad thermostat or3. low on coolant. When I rewired the O2 sensor the Mil went out, no more codes,
    From my experience on a Toyota P0125 was a disconnected or bad O2 sensor. Before cat. converter. Code p0115 is disconnected or bad coolant temperature sensor. Not the sensor that controls temp. gauge on dash but sensor that controls fuel mixture. It has a plug with 2 wires connecting. The temp. gauge sensor has one wire,and it is located on the end of the engine very close to the distributor. The coolant temp. sensor is located on the firewall side of the head also close to the distributor but it faces at a right angle to the distributor.
  • I have exactly the same behavior with a 2000 Corolla. If I unplug the oxygen sensor, a few minutes later, I get a P0125 Insufficient Coolant Temperature... followed shortly by a P0135 O2 Heater Circuit.... The latter makes sense, the former, not so much. Apparently a bug in Toyota's software.
  • on some models, Toyota does not adhere to the SAE standard definition for DTC P0125. That code can be for a Coolant Temperature Sensor concern, but it can also relate to O2 sensor function... which would make more sense that a P0135 would follow.
    Fault trace the O2 sensors and if the PCM and harness check out, replace the sensor(s) with O.E. parts.


  • I'm not trying to be confrontational - just trying to figure the darned thing out!

    Ian

    Response From Hammer Time

    That has nothing to do with the code you are getting. I actually find that hard to believe since you don't have any lean codes.

    Response From Hammer Time

    You know, this is my fault for just taking your word for the definition of this code number. After looking into the code, it appears that it has nothing at all to do with coolant temp.
    P0125




    CIRCUIT DESCRIPTION
    The Oxygen sensor (O2S) produces a voltage that varies between 0.1 V and 0.9V under normal operating conditions. The Engine Control Module (ECM) monitors this voltage and determines if the exhaust is lean or rich. If the voltage input at the ECM is about 0.1V the exhaust is lean, and if the voltage input is about 0.9V the exhaust is rich. The ECM constantly monitors the O2S 1 signal during closed loop operation and compensates for a rich or lean condition by decreasing or increasing injector pulse width as necessary.

    CONDITIONS FOR SETTING THE DTC
    After engine is at normal operating condition, O2S 1 output does not indicate RICH within 7.5 minutes when the following condition are met.

  • Engine speed at 1,500 RPM or more.
  • Vehicle speed at 25-62 MPH.
  • Throttle valve position is open.
  • Engine has been running for at least 140 seconds.

  • ACTION TAKEN WHEN THE DTC SETS
  • The ECM will illuminate the MIL during the second key cycle in which the DTC sets.
  • The ECM will store the conditions which were present when the DTC set as Freeze Frame Data.

  • CONDITIONS FOR CLEARING THE MIL/DTC
  • The ECM will turn the MIL OFF on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
  • A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault.
  • A DTC can be cleared by using the scan tool Clear Information function or by disconnecting the ECM battery feed.

  • DIAGNOSTIC AIDS
    Check for the following conditions:
  • Oxygen sensor wiring. The sensor pigtail may be mispositioned and contacting the exhaust system.
  • Poor ECM to engine grounds.
  • Fuel pressure. A condition which causes a lean exhaust can cause DTC P0125 to set. The system will go lean if pressure is too low. The ECM can compensate for some decrease. However, if fuel pressure is too low, a DTC P0125 may be set. Refer to Fuel System Diagnosis.
  • Lean injector(s).
  • Vacuum leaks. Check for disconnected or damaged vacuum hoses and for vacuum leaks at the intake manifold, throttle body, EGR system, and crankcase ventilation system.
  • Exhaust leaks. An exhaust leak may cause outside air to be pulled into the exhaust gas stream past the O2S, causing the DTC P0125 to set. Check for exhaust leaks near the O2S 1 sensor.
  • Fuel contamination. Water, even in small amounts, can be delivered to the fuel injectors. The water can cause a lean exhaust to be indicated. Excessive alcohol in the fuel can also cause this condition. Refer to Alcohol-Contaminants-In-Fuel Test for procedure to check for fuel contamination.

  • The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.

    If any wiring repairs need to be made, Refer to Repair Procedures in Diagrams.

    TEST DESCRIPTION
    Number(s) below refer to the step number(s) on the Diagnostic Table.
    1. The OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
    2. This step verifies whether the malfunction is a hard failure or an intermittence.
    1. This step verifies whether the ECM is able to receive a signal from the O2S 1.

    Response From Sidom

    You are little off base here with the code you are getting...

    Your O2 data is way off base but since it's not related to the code there is really no sense going into this right now...

    The code you posted is for an engine that is running too cool. Computer controlled engines require a minimum of 195° for peak performance. It's to the point now that and OBD II systems will actually set a code if it runs too cool after going into closed loop.

    The usual problem for this code is a stuck open T stat.

    You've changed it and even with an AM non-OE stat I would find it highly unlikely that the new aftermarket one is defective and sticking open as well. So the next thing to check would be the ECT (coolant temp) sensor and reading the PCM is getting.

    With the scanner the 1st thing you will want to do is look at the ECT PID and see if the temp is correct for how hot the engine is or wait until the morning and look at it and the temp should be very close to the ambient temp. So is it's 70 out & temp is showing 30° then you found your problem. If not it gets a little harder, you'll need to access the freeze frame data, find out when the code set & try and duplicate the conditions......

    Honestly, for a DIYer with minimal tools, you could change the T stat and then ECT sensor and connecter, if you are still getting the same code it would probably be best to take the car into a shop to have checked out....But if you have the experience to trace a possible intermittent voltage drop/short/ open in the wiring then that would be the next step before condemning the PCM.......

    Response From Hammer Time

    Yours may work. I'm not familiar with it. You just need something capable of displaying the digital coolant temp reading coming from the sensor.