GM Low Speed Data Wires - Power Steering Issue with Speedo Loss
- Thread starter Robinjo
- Start date
Robinjo
Goblin Guru
You need to check the wiring diagram for what you are working. Trying to do electrical trouble shooting without one really doesn't work. It's hard enough at times with one.
Robinjo
Goblin Guru
Ok, may have found something.
There are 5 LS data wires for the LSJ, do they all connect together at the junction (used to be a splice pack)? I only get continuity between the DLC pin 1 and BCM C2 Pin 38. High Speed data wires all have continuity as listed in post #35 above. All other Instrument Panel wires connect to their respective places as well.
The 5 are:
BCM C1 #18
BCM C1 #36
BCM C2 #38
DLC (OBD2 port) #1
Instrument Panel #9
I'm trying to look at the schematics on AllData, but if anyone has inputs that'll help I'd love to hear them.
There are 5 LS data wires for the LSJ, do they all connect together at the junction (used to be a splice pack)? I only get continuity between the DLC pin 1 and BCM C2 Pin 38. High Speed data wires all have continuity as listed in post #35 above. All other Instrument Panel wires connect to their respective places as well.
The 5 are:
BCM C1 #18
BCM C1 #36
BCM C2 #38
DLC (OBD2 port) #1
Instrument Panel #9
I'm trying to look at the schematics on AllData, but if anyone has inputs that'll help I'd love to hear them.
Robinjo
Goblin Guru
I actually found one to the DLC that was sheared and barely touching. I now have my Cluster back and it is reading the 'Power Steering Error' message again. I'll check the theft deterrent system schematic and repost the continuity check results once I have it all. When I was messing with it
I also re-hooked up your EPS unit and I still get the same 'Power Steering Error' message. SO this leads me to believe it wiring related and not unit related. Unless your was suspect?
Rttoys
Goblin Guru
I’m not sure if this helps at all, but here’s splice pack from when I was thinning the harness. Maybe you see something.
Ross
Goblin Guru
Robinjo
Goblin Guru
AllData shows that PCM C1 pin #16 going to the ODB port pin #2. I'll check that but are you sure it's tied into the LS Data bundle?
Ross
Goblin Guru
No don't include ODB port pin #2 in the low speed data bundle.
On the LSJ, one dark green wire does not get connected.
On the LSJ, one dark green wire does not get connected.
Matt3458
Member
Pictures show the wires cut out and those soldered together. Does that help at all?
Robinjo
Goblin Guru
Thanks for that, but that's all stuff I've tried a bit. That does confirm that the two I was getting no continuity to C1 pin 18 and 36 were just completely removed.
A new thing for me to test is the VSS (vehicle speed sensor) circuit. I read on some Cobalt forums that they has similar issues and it turned out to be the VSS. It's a long shot but I'll try it.
After that, I'm going to try Gtstory's EPS unit again. When I tried his unit I was having the issue of the dash display being completely useless which turned out to be a cut wire to the Instrument Panel Cluster (IPC) pin #9.
A new thing for me to test is the VSS (vehicle speed sensor) circuit. I read on some Cobalt forums that they has similar issues and it turned out to be the VSS. It's a long shot but I'll try it.
After that, I'm going to try Gtstory's EPS unit again. When I tried his unit I was having the issue of the dash display being completely useless which turned out to be a cut wire to the Instrument Panel Cluster (IPC) pin #9.
Robinjo
Goblin Guru
Got into this a bit more over the last week or so.
Checked the wires for the VSS and they had continuity from the plug to the PCM locations.
Swapped in GTStory's PS unit and though it had fixed my issue, but it came back. So, swapped my PS unit back into the car.
Next bits of information. I'm still getting the old P0315 for the Cpk Sensor not learned and now have a P0503 VSS Intermittent. I can clear the codes and everything comes back except the speedometer but the code eventually comes back. I checked the VSS and get voltage when introducing a piece of metal to the sensor end.
Next thing I'm going to try is make sure it shows voltage when the transmission turns over and then check the wires from the VSS to the PCM (not just cont. test).
Once the VSS sends info to the PCM, where does it go from there?
Checked the wires for the VSS and they had continuity from the plug to the PCM locations.
Swapped in GTStory's PS unit and though it had fixed my issue, but it came back. So, swapped my PS unit back into the car.
Next bits of information. I'm still getting the old P0315 for the Cpk Sensor not learned and now have a P0503 VSS Intermittent. I can clear the codes and everything comes back except the speedometer but the code eventually comes back. I checked the VSS and get voltage when introducing a piece of metal to the sensor end.
Next thing I'm going to try is make sure it shows voltage when the transmission turns over and then check the wires from the VSS to the PCM (not just cont. test).
Once the VSS sends info to the PCM, where does it go from there?
Robinjo
Goblin Guru
Thanks, hopefully it's just in the wires from the VSS to the PCM and I can fix it easily.
I need to link up with you sometime and return your unit since mine is ok.