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I have an 06 C6 base. The only mods are axle back exhaust and K&N intake. I got a check engine light and had the following codes: pending-p0161, p0155, p0141, p0135. Confirmed- p0056, p0050, p0036, p0030. It seems to only happen when it’s colder outside (below 45 degrees). I have cleared them before, drove 200+ miles and it was fine, but kicked the check engine light again today. I checked fuse #6 and it was fine. Does anyone have an idea of what’s going on and a solution?
I did a live view through the OBD and bank 2 sensor 1 dropped to 0v a couple times. Could that throw the rest of the codes being that they are heating related?
When I was getting 02 sensor codes right after I replaced my catalytic converters cause the right cat was clogged, and week later I picked up codes, and since the car had 75,000 miles I replaced all four.
Here was my codes on my reader.
By confirmed do you mean “current” ??...there will be a “C” after the DTC...these are all heater control DTC’s...you either have a blown fuse or a bad O2 heater circuit ground. A quick way you can confirm that the heater circuit is inop is to turn the key on with your scan tool connected...if all 4 O2 sensors read 450 millivolts (it’s bias voltage) the O2 heater circuit is not working...after a few minutes you should see the millivoltage continuously drop to below 200 Mv !!...you may have to clear the DTC’s before doing this test...I don’t have the wiring for your car so maybe someone can post it...how did you check the fuse specifically ????
By confirmed do you mean “current” ??...there will be a “C” after the DTC...these are all heater control DTC’s...you either have a blown fuse or a bad O2 heater circuit ground. A quick way you can confirm that the heater circuit is inop is to turn the key on with your scan tool connected...if all 4 O2 sensors read 450 millivolts (it’s bias voltage) the O2 heater circuit is not working...after a few minutes you should see the millivoltage continuously drop to below 200 Mv !!...you may have to clear the DTC’s before doing this test...I don’t have the wiring for your car so maybe someone can post it...how did you check the fuse specifically ????
Those codes that were confirmed were current. I pulled the fuse and it was not burnt out. When I turn the key on with the scan tool, all 4 sensors went to 450mv.
Those codes that were confirmed were current. I pulled the fuse and it was not burnt out. When I turn the key on with the scan tool, all 4 sensors went to 450mv.
What I’m saying if the heater circuit is working the millivoltage will go BELOW 450 !!...if it stays at 450 the heater circuit is not working...being that you have DTC’s for all 4 you have either bad power or ground...with a 12 volt test light connected to battery negative make sure that it lights on both sides of the fuse when installed...don’t go by a visual inspection !!
By confirmed do you mean “current” ??...there will be a “C” after the DTC...these are all heater control DTC’s...you either have a blown fuse or a bad O2 heater circuit ground. A quick way you can confirm that the heater circuit is inop is to turn the key on with your scan tool connected...if all 4 O2 sensors read 450 millivolts (it’s bias voltage) the O2 heater circuit is not working...after a few minutes you should see the millivoltage continuously drop to below 200 Mv !!...you may have to clear the DTC’s before doing this test...I don’t have the wiring for your car so maybe someone can post it...how did you check the fuse specifically ????
Thanks that good useful informations for future reference.
What I’m saying if the heater circuit is working the millivoltage will go BELOW 450 !!...if it stays at 450 the heater circuit is not working...being that you have DTC’s for all 4 you have either bad power or ground...with a 12 volt test light connected to battery negative make sure that it lights on both sides of the fuse when installed...don’t go by a visual inspection !!
Okay, I put the volt meter on both sides and it was 12 volts. I let the car sit in the on position, but not running for a few minutes and they all stayed at 450. They started dropping when running.
Thanks that good useful informations for future reference.
No problem !!...troubleshot a friends ‘04 a few weeks ago and this is how I showed him how to check it...we not only had a bad O2 sensor but also that sensor ground was bad...all 4 heater circuit grounds go to a splice pack where there are a few other grounds and then that 1 wire goes to a body ground !!...in his case it was a bad connection at the splice pack !!
Okay, I put the volt meter on both sides and it was 12 volts. I let the car sit in the on position, but not running for a few minutes and they all stayed at 450. They started dropping when running.
They are dropping because the O2 sensor itself is being heated up...the heater and sensor circuits are 2 completely different circuits !!...just to be sure I would check for power to at least 1 sensor with key on...the O2 heater circuit wires are the same color...one power and 1 ground...to check ground hook a test light to the power side of the circuit if you do indeed have 12 volts and if you can use a T pin see if the test light lights when touching the other wire which will be ground !!
They are dropping because the O2 sensor itself is being heated up...the heater and sensor circuits are 2 completely different circuits !!...just to be sure I would check for power to at least 1 sensor with key on...the O2 heater circuit wires are the same color...one power and 1 ground...to check ground hook a test light to the power side of the circuit if you do indeed have 12 volts and if you can use a T pin see if the test light lights when touching the other wire which will be ground !!
No problem !!...troubleshot a friends ‘04 a few weeks ago and this is how I showed him how to check it...we not only had a bad O2 sensor but also that sensor ground was bad...all 4 heater circuit grounds go to a splice pack where there are a few other grounds and then that 1 wire goes to a body ground !!...in his case it was a bad connection at the splice pack !!
That's why I replaced all 4 sensors, and we also found a broken wire on the right sensor at the cat, when they replaced the cat, sloppy maintenance.
I tested the passenger front sensor and it is getting 12v on connector “D”. That was using a “B” as the ground.
If D is heater power and B is heater ground the circuit appears to be OK...I use an old headlight bulb to “load” the ground to make sure the ground can carry the current back to the battery... what resistance in ohms are you seeing across the O2 heater ???....I doubt all 4 O2 sensors are bad !!!...I don’t see why you are throwing all 4 DTC’s ???
If D is heater power and B is heater ground the circuit appears to be OK...I use an old headlight bulb to “load” the ground to make sure the ground can carry the current back to the battery... what resistance in ohms are you seeing across the O2 heater ???....I doubt all 4 O2 sensors are bad !!!...I don’t see why you are throwing all 4 DTC’s ???
Sorry, I’m trying to figure all of this out. D and E will read 12v, B and D is 7v, B and E will read .20v and A and E won’t read anything
If that is from your FSM do you have the wiring schematic ??
Thats just what I pulled from the Internet, but this is what I found found for the wiring diagram. It looks like Lt Green would be the heater wire, which was E
Last edited by Belmont148133; Apr 12, 2020 at 04:32 PM.
Thats just what I pulled from the Internet, but this is what I found found for the wiring diagram. It looks like Lt Green would be the heater wire, which was E
I’m looking at the wiring for an ‘05 and it looks like the heater circuit ground is ECM controlled and NOT by a body ground...MY BAD !!...that is why your heater circuit ground says “low control” !!...with a 12 volt test light connected between D and E we would expect to see the test light flash as the ECM is grounding the power wire...you said it’s reading 12 volts so it’s probably ok !!...it’s most likely (PWM)....pulse width modulated and that is why the test light will flash!!...the car will have to be running but you said it’s reading 12 volts which tells me it’s good...and you may have to clear the codes...watch the video from 12 minutes into the video !!...hope it’s not a bad ECM !!
I’m looking at the wiring for an ‘05 and it looks like the heater circuit ground is ECM controlled and NOT by a body ground...MY BAD !!...that is why your heater circuit ground says “low control” !!...with a 12 volt test light connected between D and E we would expect to see the test light flash as the ECM is grounding the power wire...you said it’s reading 12 volts so it’s probably ok !!...it’s most likely (PWM)....pulse width modulated and that is why the test light will flash!!...the car will have to be running but you said it’s reading 12 volts which tells me it’s good...and you may have to clear the codes...watch the video from 12 minutes into the video !!...hope it’s not a bad ECM !!
Okay, so I ran the meter from my positive terminal to the light green wire, which looks like the heater, and it read 12 volts. So that green wire is acting like a ground. I then switched the meter to the negative terminal and connected to the green wire again and got nothing. I cleared the codes with the same results. Is that how the test is supposed to work?
O2 sensor Codes
