V1 Power steering / Low Fuel / rough idle

[Batmonkey]

Have a few electrical issues, which i think are all tied together. Maybe someone can help.

Get low fuel and power steering on dash. Anti left lock is on. Some times I can not shift out of park, so ill just hit the switch manually to move out of park into drive.

Ill start it sometimes it will rough idle. If i clear the engine codes it will shut off.

I do think the issue could be a wire/bad contact in j1 connector on the ECM. Ive been checking fuses, they seem to be okay. I have not checked relays. DF did my wiring harness.

It is drive-able at times. So times it will start to rough idle and cut out. I figure the best place to start is too go after the low fuel and power steering.

Any help would be great

 

[Gtstorey]

Not really enough info to trouble shoot. About I can add is it's usually a ground problem. And that the problems are about to wide spread to be a single issue, except for maybe a ground issue.

Start with one issue and trouble shoot it to the finish. You will need wiring diagrams for your donor, and some of this stuff is very hard to diagnose without a good scan tool (not just a code reader).

And add your donor to you signature so we will know what we are dealing with.

 

[Ross]

I got the "power steering on dash" when data wasn't flowing thru the GM high speed LAN wires. For me, a new connector for the LAN wires at the power steering unit fixed the problem.

I'm not sure what your donor car was, most of us put it in our signature.

 

[Batmonkey]

I got the "power steering on dash" when data wasn't flowing thru the GM high speed LAN wires. For me, a new connector for the LAN wires at the power steering unit fixed the problem.

I'm not sure what your donor car was, most of us put it in our signature.

The tan data wires?

 

[Gtstorey]

Ross is correct, High Speed LAN (Tan data wires) could cause several of your issues, although I don't think the shifter problem is one of those.

There is a resistance test included here that might tell you something about how the high speed is communicating.
SECTION ‘X’ CONTENTS (aeswave.com)

 

[Batmonkey]

I got the "power steering on dash" when data wasn't flowing thru the GM high speed LAN wires. For me, a new connector for the LAN wires at the power steering unit fixed the problem.

I'm not sure what your donor car was, most of us put it in our signature.

Do you have any testing instructions for the ecm connector. I get issues when I wiggle those wires but I can't narrow it down to which wire.

 

[Gtstorey]

Not sure there is a "test" for the ECM connector, too many wires involved for a single test. You will have to look at each circuit independently. This is where a scan tool is very useful so you can see what drops out during wiggle test.

Since this is so close to the fuse box, you could also be affecting the connections on the bottom of the fuse box. There have been more issues with individual wires being loose in the fuse box connectors than the ECM connectors.

 

[Batmonkey]

Not sure there is a "test" for the ECM connector, too many wires involved for a single test. You will have to look at each circuit independently. This is where a scan tool is very useful so you can see what drops out during wiggle test.

Since this is so close to the fuse box, you could also be affecting the connections on the bottom of the fuse box. There have been more issues with individual wires being loose in the fuse box connectors than the ECM connectors.

I have been pulling some individual pins having a look at it. Wanted to test the connections of them individually.

Going over grounds they all look pretty good. I added and extra ground to my tcm which I thought fixed some issues before.

 

[Gtstorey]

Each individual circuit on the ecm would have to be evaluated to determine how to test it. About all you can do as a general test is to check continuity to where they land.

What trouble codes are you getting?

 

[Batmonkey]

Each individual circuit on the ecm would have to be evaluated to determine how to test it. About all you can do as a general test is to check continuity to where they land.

What trouble codes are you getting?

It varies, right now, im getting

P0118 Engine coolant temp sensor 1 circuit high
P0013 B camshaft position - actuator circuit / open bank 1
P0122, throttle/pedal position sensor/switch a circuit low
P0223 - Throttle/pedal posiiton sensor/switch B circuit High

I attached a new throttle body sensor and didn't change the codes.


P0443 / P0449/p0452 some evap codes

 

[Joebob]

I would unwrap the ECM harnesses and look at the wires and this link to what the wires should be and do the wiggle test on each wire. I was one that had wire pin connectors loose while the plug was on tight. No fault of DF or anyone working the harness, the connectors stretch and were never made for on/off cycling. Anyway, I got a paperclip that is the same diameter as the BCM/ECU pins and inserted into each circuit in the plug. Found out my BCM plug has a couple of loose pins (it was also the tan/tan black twisted pair of wires that everyone talks about). That pair is the data link between the computers, if it goes down, so does the car.

Look over the link for the plugs function and see if you can find a common theme with the issues. It most likely is a ground that might be shared amongst those functins. Also there is an engine ground near the oil filter that gives people a hard time as well.

Good luck.

BAR-AIR's build up in Buffalo N.Y.

Yes those are 5 3/4” lenses. Just make sure they are the DOT lenses. Those were advertised as DOT lenses but when they showed up no DOT markings. Took about a month of back and forth with the manufacturer before they sent a set of DOT lenses. Nate’s car is using a set of 5 3/4” headlight shells...

dfkitcar.com

 

[Batmonkey]

I would unwrap the ECM harnesses and look at the wires and this link to what the wires should be and do the wiggle test on each wire. I was one that had wire pin connectors loose while the plug was on tight. No fault of DF or anyone working the harness, the connectors stretch and were never made for on/off cycling. Anyway, I got a paperclip that is the same diameter as the BCM/ECU pins and inserted into each circuit in the plug. Found out my BCM plug has a couple of loose pins (it was also the tan/tan black twisted pair of wires that everyone talks about). That pair is the data link between the computers, if it goes down, so does the car.

Look over the link for the plugs function and see if you can find a common theme with the issues. It most likely is a ground that might be shared amongst those functins. Also there is an engine ground near the oil filter that gives people a hard time as well.

Good luck.

BAR-AIR's build up in Buffalo N.Y.

Yes those are 5 3/4” lenses. Just make sure they are the DOT lenses. Those were advertised as DOT lenses but when they showed up no DOT markings. Took about a month of back and forth with the manufacturer before they sent a set of DOT lenses. Nate’s car is using a set of 5 3/4” headlight shells...

dfkitcar.com

How did you fix it, did you put on new connectors

 

[Joebob]

I went to the local junkyard and pulled BCM plugs as well as ECU just in case. I tried depinning the stock plug to put an unused but good pin in the needed spot, but the clips are brittle and broke. Even one of the two junk yard plugs broke. Got it all repaired, soldered in the new lines and all is good for more than 6 months.

 

[Robinjo]

Before going through all that I would triple check the grounds. Make sure the studs are completely clean, no paint at all. Then make sure they are all seated well and tight.

 

[Batmonkey]

Before going through all that I would triple check the grounds. Make sure the studs are completely clean, no paint at all. Then make sure they are all seated well and tight.

I check every ground with a volt meter, one to a positive then one to the ground and if it reads 12.2+ I assume its good. Not sure if that is a correct way to check.

Unless I am missing a ground somewhere completely.

 

[RCK605]

When I finished my harness I checked continuity from each ground pin on the connectors to the ground lugs and found a ground that I missed. Then once the harness was installed I checked continuity between the ground lugs to make sure they had good contact at the studs. So far haven't had any electrical problems related to grounds. Just the 2 amp fuse on the BCM.

 

[Gtstorey]

I check every ground with a volt meter, one to a positive then one to the ground and if it reads 12.2+ I assume its good. Not sure if that is a correct way to check.

Unless I am missing a ground somewhere completely.

Actually, 12.2 sounds a little low for a decently charged battery. And even then it's not a good indication of it's current carrying abilities. A better check is with an 12v incandescent light bulb.

 

[Markm]

I rarely use an ohm meter to test for good grounds due to the fact that if it has one good strand of wire connected it’ll give you a good reading, I typically use an old headlamp bulb and load test circuits cause it’s easy to see the light not entirely bright on a bad circuit. Be easy on the ecm connector pins cause the micro 64 terminals are not tolerant of probing with anything other than test leads. I would start by load testing the circuits for the ect use the ecm connector to supply the power and ground and plug the bulb in at the ect connector then wiggle the harness to help narrow down the area to inspect

 

[Batmonkey]

Just got my hands on a more detailed scanner autel mk808, which is much better than I had before, but its way too detailed. I dont even know where to start. Apparently this is a problem amongst cobalt. Every video I watch there is a different fix. I really don't want to pull the whole wiring harness out. I've been going through grounds, and checking continuity. I have been checking the sensors on the scanner to see if reads the 5 volt reference and it seems like they do. I may try and swap and ECM but I don't think it is.

 

[Gtstorey]

The service manual will give you "normal" values for almost everything that the scanner reads, and beyond that you have to see if things are reacting as the should to raw data. It also gives you the state of modules, error codes beyond powertrain/ECM, and also see signals like start commands to see what isn't getting through. If it's you first time using one, you will have to play with it and try to figure out what data looks wrong if the trouble codes don't lead you to a problem.