Project Undertow #388

Dominicnicklyn

Dominicnicklyn

Well-Known Member
Ross said:
This sounds like some of the issues I was having. The solution to my goblin's issues was
1. poor connection on the connectors under the fusebox, (reseating the connectors fixed this)
2. bad data connector at the power steering (bought a connector from an auto recycle yard, soldered it on)
3. replaced the power steering unit with used one.
I also cleaned every ground wire and retorqued all 3 of my grounding points, which have a bunch of ground wires on each one.

When your data is flowing enough to move the throttle butterfly, I wonder if jumping the starter motor would allow it to run. On my LSJ, I ran the purple starter wire into the cabin, so I could connect it to accessory 12V power, and jump the starter quickly, while in traffic. I had to do this for about 6 months, as it took that long for me to debug my data issues.
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Yes, I was thinking about this while laying in bed last night.

I'm starting to belive that I solved the original issue and now I have a bad ECM ground. I only lose coms with the ECM atm.

I'll check the fuse block plugs, but I've already set them in 3 different times believing they weren't making good contact. (Had to jb weld some plastics due to over tightening them)

I've done all of your solutions above. Even swaped ecm/bcm/ignition from another same model lsj.

I'll dive deeper when I get home from work.
 
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Gtstorey

Goblin Guru
I had to unplug the individual wires from the fuse box to plugs and tighten the individual connections to get mine to stop having intermittent issues. And the more you have messed with the plugs, the more likely you are to have this problem.
 
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Gtstorey

Goblin Guru
But I would still start by confirming your missing “black” ECM wire is a ground and reconnecting if it is. I don’t expect any of the ECM to be unnecessary.
 
Dominicnicklyn

Dominicnicklyn

Well-Known Member
Anyone know where the power wire(s) are on the p12 ecm?

I want to test and see if I'm getting the voltage I need for the ecm to work properly. It's acting like on key "on" that it has power and is working how it should. Then if I let it sit for a short bit (30 sec to a couple min) that it doesn't have power.
 
Ross

Ross

Goblin Guru
Red wires on a Cobalt are typically "battery positive voltage" wires,
then once they go thru a fuse, are Red wires with a White stripe.
If they also go thru the run/start relay, then they are typically Pink wires, that are switched by the key.
 
Dominicnicklyn

Dominicnicklyn

Well-Known Member
Ross said:
Red wires on a Cobalt are typically "battery positive voltage" wires,
then once they go thru a fuse, are Red wires with a White stripe.
If they also go thru the run/start relay, then they are typically Pink wires, that are switched by the key.
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Your the man, I strive to be knowledgeable like you good sir
 
Dominicnicklyn

Dominicnicklyn

Well-Known Member
While testing voltage drop on every power imaginable, I noticed that this pink wire on the EPS module doesn't have power when the key is on. Anyone know if I should have power here, still no coms with the EPS module with solid theft light and no throttle body response?
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Gtstorey

Goblin Guru
That circuit has a lot of failure points. But yes it should have power with the key in run position. If you track it back to no on signal at the run/crank relay, I’ll dig out the control wiring side diagram of the relay.
 

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Dominicnicklyn

Dominicnicklyn

Well-Known Member
Gtstorey said:
That circuit has a lot of failure points. But yes it should have power with the key in run position. If you track it back to no on signal at the run/crank relay, I’ll dig out the control wiring side diagram of the relay.
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Your my savior, also do you have the book that these diagram came from?

I'd like to find one to purchase for future projects
 
Dominicnicklyn

Dominicnicklyn

Well-Known Member
Gtstorey said:
That circuit has a lot of failure points. But yes it should have power with the key in run position. If you track it back to no on signal at the run/crank relay, I’ll dig out the control wiring side diagram of the relay.
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Another thing, seems that my bcm doesn't utilize fuse 19. Fuse 7 (2A) is the only one that would be for the power steering (also doesn't have power with key on)
 
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Gtstorey

Goblin Guru
Dominicnicklyn said:
Another thing, seems that my bcm doesn't utilize fuse 19. Fuse 7 (2A) is the only one that would be for the power steering (also doesn't have power with key on)
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Based upon what? My service manual is for 2010 so it might be wrong but I think I have found one wire color difference from my 09 (and that is likely an error instead a true difference in color). Have you pulled the wiring diagrams for your donor year? BCM fuse 7 is instrument cluster and DIC if it had that option in my manual.

And 7 should be hot all of the time, not ignition switched.
 
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Gtstorey

Goblin Guru
Sorry, I must have seen the wrong signature when checking donor on my phone. I thought you had an 08. I must have looked at the wrong post.

Beyond that, figuring out why a circuit doesn’t have power shouldn’t take long if you use your wiring diagram and start checking at one end and trace the chain all the way back to the battery.
 
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Gtstorey

Goblin Guru
Of course you could just run a temporary power wire to your eps and see if that is the cause of the no data issue.With a fused source.
 
Dominicnicklyn

Dominicnicklyn

Well-Known Member
Gtstorey said:
Of course you could just run a temporary power wire to your eps and see if that is the cause of the no data issue.With a fused source.
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So, ended up doing exactly that. Left a 2A fuse in the bcm and ran a 12v power with another 2A fuse to the power steering. Immediately after hooking both up I heard relays click and my dash lights all worked.

Ran tech2win and have coms with everything except the theft deterrent module. Tried cranking, and what do I know. STARTER TURNED OVER!!!

Thanks everyone! I know it was a slow process but trust me, this has been bothering me for so long.

Now I need to solve my power issue in the power steering and steering wheel button circuit. Any tips or recommendations are welcome. Honestly have little experience chasing something this far back in the circuit. (2A, fuse 7 on 06 lsj BCM)
 
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Gtstorey

Goblin Guru
Steering wheel button?

Again, have you pulled the wiring diagram for your donor for the eps? You are making things a lot harder on yourself if you are trying to work on this stuff without one.
 
Dominicnicklyn

Dominicnicklyn

Well-Known Member
Gtstorey said:
Steering wheel button?

Again, have you pulled the wiring diagram for your donor for the eps? You are making things a lot harder on yourself if you are trying to work on this stuff without one.
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I have quite a bit from when Ross had his Alldata, but it expired so I don't have every diagram and pinout.

I'm currently looking for whatever I can to help out.
 
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