Okay... here is my issue. Check engine light came on, stopped at parts store, pulled the code. P0138 came up bank 1 sensor 2 high voltage. Replaced sensor, reset CPU, 40 minutes of driving later light came back on, stopped at parts store and the same code. No funny smell out of the exaust. any suggestions?
P0138 code problems
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wake_100
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Okay... here is my issue. Check engine light came on, stopped at parts store, pulled the code. P0138 came up bank 1 sensor 2 high voltage. Replaced sensor, reset CPU, 40 minutes of driving later light came back on, stopped at parts store and the same code. No funny smell out of the exaust. any suggestions?
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According to http://www.scangauge.com/support/pdfs/XGAUGE.pdf you can configure the XGAUGE feature to monitor the O2 sensor values.wake_100 said:
I suppose that if you have a wiring problem, the O2 value for this sensor will remain at a constant value rather than constantly fluctuating as the ECM varies the A/F mixtures.
I was also wondering if the correct sensor was replaced. I once replaced the wrong O2 sensor in a Honda because I wasn't aware there were others on this particular model.
you mean multiple sensors? with the 2.4 there is only 2 sensors. I checked the sensors for resisitance and they check okay as per service manual but we'll say something is on sensor one (upstream) that wouldnt change the value of the resistance I think. I think if sensor one was coated in soot it would make it rich making sensor two high voltage?
I am wondering about my vacuum system in it to. I can sit at a stop light, and just stretch my leg pressing the brake pedal and I can set of the stability control. it'll beep and the light of the car with skid marks under it will light up. can reproduce it 100%
I am wondering about my vacuum system in it to. I can sit at a stop light, and just stretch my leg pressing the brake pedal and I can set of the stability control. it'll beep and the light of the car with skid marks under it will light up. can reproduce it 100%
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Your O2 sensors are fed by two different circuits.wake_100 said:
The first circuit is the heater circuit, and the other is the O2 detection circuit.
O2 sensors only work properly when they reach a certain temperature. In the old days they didn't work until the exhaust manifold was hot enough to provide the proper temperature. In today's cars they use heated sensors. The ECM provides a voltage solely to heat up the sensors to provide O2 data sooner than the old time technology. Faults with the heater circuit will normally give a different diagnostic code than the one you are getting.
The second circuit supplies battery voltage on one wire, and depending on what the O2 levels are, the sensor sends varying voltage back on a second wire. The code you are getting implies that this return voltage is higher than anything that should be normally seen. Therefore, either your sensor is defective, and is sending the battery voltage back on the signal wire, or a short somewhere in the harness is sending voltage back to the signal terminal of the ECM. The diagnostic charts in the PDF will help you determine where the problem is.
wake_100 said:
That is you HAC feature. Have a look at http://rav4world.com/forums/viewtopic.php?t=14769
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There are many ways. The plastic dividers inside a connector may have broken which allows two wires to touch each other. The wiring harness touching a sharp piece of metal could cut through the insulation. A connector full of wet salt water would allow current flow between conductors.wake_100 said:
Until you follow the procedure in the PDF file, you are just speculating that the problem is defective wiring.
Are you saying that you think the vibration caused your diagnostic code?wake_100 said:
Oh my phone is annoying me.
Right now I printed the guide and am reading through it. I can't look at the car I'd like to trade in right now as I'm at work.
I drove to my destination, parked it for a few hours, it was cold out maybe 7 degrees out. When I left about 20-30 minutes later the lights were on. It may be coincidence.
Right now I printed the guide and am reading through it. I can't look at the car I'd like to trade in right now as I'm at work.
I drove to my destination, parked it for a few hours, it was cold out maybe 7 degrees out. When I left about 20-30 minutes later the lights were on. It may be coincidence.
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If the ECM had detected a problem with the heater circuit, you would have obtained a P0037, P0038 or a P0141 code. You can look at the following PDF file for information on troubleshooting one of these codes. Linkwake_100 said:
Your code, P0038, indicates that the voltage seen between pins 64 & 87, on the B30 connector of the ECM, is higher than it should be. Pins 64 & 87 at the ECM are connected to Pins 3 & 4 (respectively) on the O2 sensor.
I don't know if you have a Scangauge, or if you were just asking out of curiousity, but if you do, use it to see if the O2 readings are changing, or if they are locked at a fixed value.
If you see the voltages are fixed, then unplug the O2 sensor and see if they drop to zero. If they drop to zero, then the high voltage is coming from the sensor. If the voltage doesn't drop, then it is coming from a short circuit within the harness, or it is a defective ECM.
If you don't have a Scanguage, then unplug the sensor and you should get a P0137 code ( a low voltage error). If you don't get the P0137 then you still have wiring problems.
Be aware that when you unplug the O2 sensor you will also get a P0037 ( and possibly a P01410) because the heater circuit will also look failed.
I dont have a scanguage, really thinking about getting one now... Thanks for your help so far. I have an appointment tomorrow to take it to the dealership and see how badly they try to rip me off... :/
and why does it take 20 minutes to almost an hour for the light to come back on? i would think there would be a faster response from the ECU
and why does it take 20 minutes to almost an hour for the light to come back on? i would think there would be a faster response from the ECU
Did you ever say which sensor you changed? Hope it was the downstream sensor: http://www.obd-codes.com/p0138
kinda, maybe I wasnt clear but yes it was sensor 2 also known as the downstream sensor. the one after the cat. im wondering because it was a bosch sensor i replaced it with also :/ I ohmed out the original sensor according to the service manual and it checked good
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It may not be the sensor. The system uses two O2 sensors, a narrowband one in the exhaust manifold to set the air/fuel ratio to 14.7:1. The downstream one is a wideband which checks if the AFR is set right AND the catalytic converter is doing its job.
My RAV4 replaced a Subaru Forester which kept giving a downstream code which I didn't believe was the sensor itself partly because as you mentioned it doesn't come on instantly. On eBay I found a listing for a catalytic converter that said "keeps the code (they gave the specific one) from repeatedly coming on." Bought and installed their converter - end of problem.
My RAV4 replaced a Subaru Forester which kept giving a downstream code which I didn't believe was the sensor itself partly because as you mentioned it doesn't come on instantly. On eBay I found a listing for a catalytic converter that said "keeps the code (they gave the specific one) from repeatedly coming on." Bought and installed their converter - end of problem.
Okay, my post overlapped your latest. Replacing the narrowband sensor is a lot easier than the cat!wake_100 said:
Have a P0138 code on 2006 Rav4 (secondary O2 sensor). Installed a new Bosch O2 sensor and cleared the code. Check engine back on in a few trips, same code.
Brought my scan tool over to view live data. The rear O2 showing zero voltage.
At the 4 wire connector FROM the vehicle, one wire has 12v for the heater, guessing 2 other wires are eventual grounds, but isn't the 4th wire suppose to have a reference voltage for the O2 sensor? Something like .3 to .5 volts?
Trying to determine if it's related, but just prior to the check engine light illuminating (a few startups ago) the Rav4 was at the Toyota dealer for a recall regarding the sticking throttle situation, involving a software upgrade and some cable replaced. Unsure if they touched or replaced the ECM.
Vehicle starts and runs fine, no drivability issues.
Brought my scan tool over to view live data. The rear O2 showing zero voltage.
At the 4 wire connector FROM the vehicle, one wire has 12v for the heater, guessing 2 other wires are eventual grounds, but isn't the 4th wire suppose to have a reference voltage for the O2 sensor? Something like .3 to .5 volts?
Trying to determine if it's related, but just prior to the check engine light illuminating (a few startups ago) the Rav4 was at the Toyota dealer for a recall regarding the sticking throttle situation, involving a software upgrade and some cable replaced. Unsure if they touched or replaced the ECM.
Vehicle starts and runs fine, no drivability issues.
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