Wiring help
Thread Starter
New Member
Joined: 01-06-23
Posts: 19
Likes: 0
From: florida
Wiring help
Having a problem with my o2 sensor not reading. Replaced sensor and still had the same problem, so I checked both the new and old sensor and they are both good. The code I’m getting is for the heater circuit. I have checked the wiring harness with a meter and I don’t have any breaks. I have power coming from the pcm to the connector. Today it is having codes for the air intake temp sensor circuit not consistent a maf code that comes and goes and possibly another code that I don’t remember. It seems like all the codes I’m getting use the same fuse from what I’ve gathered. The fuse isn’t bad and I have power at the fuse. The only thing I haven’t done yet is a load test. If anyone has a wiring diagram or any ideas I’d like to hear them. I’m kinda leaning towards possibly a bad pcm but am going to do a load test before I spend $500 on a new pcm. Reason I think it might be pcm, recently the car has done a thing where it won’t crank over and has died while driving. While it’s doing this the check engine isn’t lit up on the dash with the key in the on position, cooling fans don’t turn on and the fuel pump don’t turn on. If I mess with the connector that goes into the pcm the car will run again but my o2 senor still won’t work. It idles great, runs like **** while at a steady speed, runs great its light acceleration and great at wot
Get the wiring diagrams before dropping money on the ecu. Also don't buy a new PCM/ECU when there is a perfectly good used 2009 PCM/ECU in the classifieds on this site (shameless plug for my listing)
Here come the questions to help understand the problem:
When you say you mess with the connector to the pcm, which of the two connectors are you moving? I'm assuming you mean moving the wires, the connection should have zero movement. I would also suggest you pull back the loom in the area of the connector and inspect the wires for physical damage, how you word the problem leads me to think there is a wiring issue but not a dead short or cut wire.
Did you or a shop replace any other parts prior to this issue coming up?
What actual codes are being set? Just listing the generic text doesn't help a lot with diagnosis.
Which o2 sensor did you replace sensor 1 or sensor 2?
What is brand and part number of replacement o2 sensor?
How are you testing the sensors to tell if they're good?
Here come the questions to help understand the problem:
When you say you mess with the connector to the pcm, which of the two connectors are you moving? I'm assuming you mean moving the wires, the connection should have zero movement. I would also suggest you pull back the loom in the area of the connector and inspect the wires for physical damage, how you word the problem leads me to think there is a wiring issue but not a dead short or cut wire.
Did you or a shop replace any other parts prior to this issue coming up?
What actual codes are being set? Just listing the generic text doesn't help a lot with diagnosis.
Which o2 sensor did you replace sensor 1 or sensor 2?
What is brand and part number of replacement o2 sensor?
How are you testing the sensors to tell if they're good?
Thread Starter
New Member
Joined: 01-06-23
Posts: 19
Likes: 0
From: florida
[QUOTE=ECaulk;7759472]Get the wiring diagrams before dropping money on the ecu. Also don't buy a new PCM/ECU when there is a perfectly good used 2009 PCM/ECU in the classifieds on this site (shameless plug for my listing)
Here come the questions to help understand the problem:
When you say you mess with the connector to the pcm, which of the two connectors are you moving? I'm assuming you mean moving the wires, the connection should have zero movement. I would also suggest you pull back the loom in the area of the connector and inspect the wires for physical damage, how you word the problem leads me to think there is a wiring issue but not a dead short or cut wire.
Did you or a shop replace any other parts prior to this issue coming up?
What actual codes are being set? Just listing the generic text doesn't help a lot with diagnosis.
Which o2 sensor did you replace sensor 1 or sensor 2?
What is brand and part number of replacement o2 sensor?
How are you testing the sensors to tell if they're good?[/QUOT
O2 codes- po64D-00 and po030-00. It’s for sensor one. I ohm tested both the old sensor and new one, checked with volt meter to see if there’s power at the connector and there is. I just got done load testing some wires and the wiring is all good. My air intake temp sensor is now throwing a code for voltage to high and voltage inconsistent. Don’t remember what those codes were. Also have a new code for tps sensor, don’t remember what that one was either, however I was looking at live data on my scanner and it was saying it was 100percent open. I traced the wires back to the pcm and started moving those wires around. While doing that I watched the percentage of the tps drop to normal and jump around. A couple of the pins that are in the bigger connector broke while I was trying to separate the connector to have a look at the pins. So now I either gotta replace pins or buy another harness and hopefully this solves my problem. I’ve even gone as far as opening up the pcm cause I heard something loose inside it but it was just a little piece of the glue, the circuit board, resistors ect all look fine in there.
No other work was done prior to these problems. There’s very few people who I will let work on my car cause I used to work in the industry and have seen to many hacks to trust.
Here come the questions to help understand the problem:
When you say you mess with the connector to the pcm, which of the two connectors are you moving? I'm assuming you mean moving the wires, the connection should have zero movement. I would also suggest you pull back the loom in the area of the connector and inspect the wires for physical damage, how you word the problem leads me to think there is a wiring issue but not a dead short or cut wire.
Did you or a shop replace any other parts prior to this issue coming up?
What actual codes are being set? Just listing the generic text doesn't help a lot with diagnosis.
Which o2 sensor did you replace sensor 1 or sensor 2?
What is brand and part number of replacement o2 sensor?
How are you testing the sensors to tell if they're good?[/QUOT
O2 codes- po64D-00 and po030-00. It’s for sensor one. I ohm tested both the old sensor and new one, checked with volt meter to see if there’s power at the connector and there is. I just got done load testing some wires and the wiring is all good. My air intake temp sensor is now throwing a code for voltage to high and voltage inconsistent. Don’t remember what those codes were. Also have a new code for tps sensor, don’t remember what that one was either, however I was looking at live data on my scanner and it was saying it was 100percent open. I traced the wires back to the pcm and started moving those wires around. While doing that I watched the percentage of the tps drop to normal and jump around. A couple of the pins that are in the bigger connector broke while I was trying to separate the connector to have a look at the pins. So now I either gotta replace pins or buy another harness and hopefully this solves my problem. I’ve even gone as far as opening up the pcm cause I heard something loose inside it but it was just a little piece of the glue, the circuit board, resistors ect all look fine in there.
No other work was done prior to these problems. There’s very few people who I will let work on my car cause I used to work in the industry and have seen to many hacks to trust.
New Member
Joined: 11-20-16
Posts: 7
Likes: 0
From: Spokane, Washington
I don't really have anything helpful to add on this other than I'm having a similar issue but I never really considered they were related. I had intermittent IAT and MAF codes, which is now just a consistant MAF code and my O2 seems to come and go despite replacing it.
These are the wiring diagrams I have been trying to use to sort my issue and they seem correct for my 2010 SS so hopefully that helps you in some way.
These intermittent electrical issues are the worst I swear, it's making me consider getting something a little newer I swear. Hopefully you have better luck than I have with this.
These are the wiring diagrams I have been trying to use to sort my issue and they seem correct for my 2010 SS so hopefully that helps you in some way.
These intermittent electrical issues are the worst I swear, it's making me consider getting something a little newer I swear. Hopefully you have better luck than I have with this.
[QUOTE=94ltz2;7759479]
I wonder if one of the pins in the large connector is to the o2 sensor and that's what caused the P064D, which would require a new ECU since the controller is in the ECU. From an old thread on here the wire to the o2 sensor rested against the head and caused a short that likely fried his ECU, thread: https://www.cobaltss.net/forums/prob...needed-321883/
Going from memory the LNF ECU is the same Bosch ECU used in a lot of VW and Audi's, you might be able to find the connector and replacement pins through a VW/Audi vendor. I would assume trying to find a wiring harness for the cobalt is going to be difficult.
Get the wiring diagrams before dropping money on the ecu. Also don't buy a new PCM/ECU when there is a perfectly good used 2009 PCM/ECU in the classifieds on this site (shameless plug for my listing)
Here come the questions to help understand the problem:
When you say you mess with the connector to the pcm, which of the two connectors are you moving? I'm assuming you mean moving the wires, the connection should have zero movement. I would also suggest you pull back the loom in the area of the connector and inspect the wires for physical damage, how you word the problem leads me to think there is a wiring issue but not a dead short or cut wire.
Did you or a shop replace any other parts prior to this issue coming up?
What actual codes are being set? Just listing the generic text doesn't help a lot with diagnosis.
Which o2 sensor did you replace sensor 1 or sensor 2?
What is brand and part number of replacement o2 sensor?
How are you testing the sensors to tell if they're good?[/QUOT
O2 codes- po64D-00 and po030-00. It’s for sensor one. I ohm tested both the old sensor and new one, checked with volt meter to see if there’s power at the connector and there is. I just got done load testing some wires and the wiring is all good. My air intake temp sensor is now throwing a code for voltage to high and voltage inconsistent. Don’t remember what those codes were. Also have a new code for tps sensor, don’t remember what that one was either, however I was looking at live data on my scanner and it was saying it was 100percent open. I traced the wires back to the pcm and started moving those wires around. While doing that I watched the percentage of the tps drop to normal and jump around. A couple of the pins that are in the bigger connector broke while I was trying to separate the connector to have a look at the pins. So now I either gotta replace pins or buy another harness and hopefully this solves my problem. I’ve even gone as far as opening up the pcm cause I heard something loose inside it but it was just a little piece of the glue, the circuit board, resistors ect all look fine in there.
No other work was done prior to these problems. There’s very few people who I will let work on my car cause I used to work in the industry and have seen to many hacks to trust.
Here come the questions to help understand the problem:
When you say you mess with the connector to the pcm, which of the two connectors are you moving? I'm assuming you mean moving the wires, the connection should have zero movement. I would also suggest you pull back the loom in the area of the connector and inspect the wires for physical damage, how you word the problem leads me to think there is a wiring issue but not a dead short or cut wire.
Did you or a shop replace any other parts prior to this issue coming up?
What actual codes are being set? Just listing the generic text doesn't help a lot with diagnosis.
Which o2 sensor did you replace sensor 1 or sensor 2?
What is brand and part number of replacement o2 sensor?
How are you testing the sensors to tell if they're good?[/QUOT
O2 codes- po64D-00 and po030-00. It’s for sensor one. I ohm tested both the old sensor and new one, checked with volt meter to see if there’s power at the connector and there is. I just got done load testing some wires and the wiring is all good. My air intake temp sensor is now throwing a code for voltage to high and voltage inconsistent. Don’t remember what those codes were. Also have a new code for tps sensor, don’t remember what that one was either, however I was looking at live data on my scanner and it was saying it was 100percent open. I traced the wires back to the pcm and started moving those wires around. While doing that I watched the percentage of the tps drop to normal and jump around. A couple of the pins that are in the bigger connector broke while I was trying to separate the connector to have a look at the pins. So now I either gotta replace pins or buy another harness and hopefully this solves my problem. I’ve even gone as far as opening up the pcm cause I heard something loose inside it but it was just a little piece of the glue, the circuit board, resistors ect all look fine in there.
No other work was done prior to these problems. There’s very few people who I will let work on my car cause I used to work in the industry and have seen to many hacks to trust.
Going from memory the LNF ECU is the same Bosch ECU used in a lot of VW and Audi's, you might be able to find the connector and replacement pins through a VW/Audi vendor. I would assume trying to find a wiring harness for the cobalt is going to be difficult.
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