Project Undertow #388

[Dominicnicklyn]

So some good news and some bad news.

Good news is that I replaced the EPS module and I now have coms. The dash now lights up and I have solid ABS, seat belt, and theft lights.
During key on I believe I can hear the intercooler pump run but I couldn't tell by touching it and it was too difficult to try and unplug.

The bad news is that I've found myself one again not knowing what to go off of.
Tech2win says that I don't have coms with the PCM. I didn't check if the butterfly was moving or not due to running out of time.

 

[Dominicnicklyn]

 

[Dominicnicklyn]

I'm also looking through my donor bolts and I can't seem to find the two bolts that connect the spindle on the rear control arm to the engine cradle. Is anyone has a part number or bolt specs I would appreciate it.

If I can get the control arms bolted on I can put the rest of the suspension on the car. Hopefully I can get the engine to run/crank soon

 

[Dominicnicklyn]

Do you happen to remember what you ended up doing with 24 and 47? I now have the same two wires hanging out and wondering what to do with them.

I honestly still haven't sorted them out. The instructional build videos were for a new gen.

If anyone has our answer please leave it here.

 

[finazzoty]

I honestly still haven't sorted them out. The instructional build videos were for a new gen.

If anyone has our answer please leave it here.

These are not used so you can leave them be

 

[Dominicnicklyn]

So I'm back at it again. The dash now lights up like it should and I now have a solid theft light.

Tech2win says that I don't have coms with the ECM. Butterfly doesn't move on key on but the intercooler pump is running (no idea on fuel pump due to wiring it wrong).

I can read and write the ECM with my bench harness so I know that it's not bricked.

I've tried the key relearn but nothing came of it. Any ideas on where to check?

 

[Gtstorey]

Hard to tell what you have tried already with this spread over several months. Have you checked for 60ohms on the data wires? Have you ensured all of the power wires to the ECM actually have power to wake it up? If it communicates on the bench it should communicate in the car if the data and power wires are correct.

 

[Ross]

The GM high speed LAN isn't communicating. Could be wiring, could be a bad computer. The signal goes from the OBDii port thru the electronc power steering (EPS), thru the body control module (BCM), to the power control module (PCM).

 

[Dominicnicklyn]

The GM high speed LAN isn't communicating. Could be wiring, could be a bad computer. The signal goes from the OBDii port thru the electronc power steering (EPS), thru the body control module (BCM), to the power control module (PCM).

I've ensured continuity on all the data wires (doesn't determine if they are working correctly).
My PCM works on my bench harness but not on the car. Any way I can check power and ground to the PCM?

Would the antitheft keep the PCM from communicating with the rest of the car?
I've done the relearn procedure but the light stays on solid after the 10 minutes.

 

[Gtstorey]

I don’t think anti theft will keep it from communicating..

Still no answer on the 60 ohms on the data circuit?

 

[Ross]

I've ensured continuity on all the data wires (doesn't determine if they are working correctly).
My PCM works on my bench harness but not on the car. Any way I can check power and ground to the PCM?

Would the antitheft keep the PCM from communicating with the rest of the car?
I've done the relearn procedure but the light stays on solid after the 10 minutes.

You could back probe the PCM connections. Kind of a pain... take the cover off, and use needles. If you try to run the needle down to the copper connector, you run the risk of wrecking the waterproof nature of the connectors. I usually just stab the wire thru the insulation, which also wrecks the waterproof nature, but at least the water isn't inside the connector with 40 other connections.

 

[Dominicnicklyn]

I don’t think anti theft will keep it from communicating..

Still no answer on the 60 ohms on the data circuit?

It's kind of weird but here it goes

Testing from the OBDll port
Key off : 73.7 ohms
Key on : 128 ohms (fluctuates)

Bench harness reads 118.7 ohms while keyed on

I haven't tested power to the plug on the ECM yet but I should be able to tomorrow

 

[Gtstorey]

You likely have some issues with your data wiring. Bench harness at almost 120 ok since it only has one resistor in the ECM. Check the power steering module by itself and see if it measures 120 ohms.
You might have something else shorting to your data wires causing fluctuating readings. I’ve posted a link several times to an aeswave site that explains how the data should work and some expected voltages, although that is a little hard to measure with a regular voltmeter.

And add your donor to your signature. It helps to know which diagrams will apply.

 

[escapepilot]

My memory is horrible on which particular wire it is, but there is one of the green data wires in the LSJ harness that doesn't get grouped with all of the others. It is where about 6 or 7 green ones get cut from the black cluster then all soldered together in the video.

 

[Dominicnicklyn]

My memory is horrible on which particular wire it is, but there is one of the green data wires in the LSJ harness that doesn't get grouped with all of the others. It is where about 6 or 7 green ones get cut from the black cluster then all soldered together in the video.

Any idea on that one that gets left out?

I belive I put them all together

 

[Robinjo]

There was a post on it a long time ago, I can't remember who started it. I do remember there were steps to check on the OBD2 port to see if you had messed it up or not. You check continuity through pin #1 and #2 to see if you wired it up wrong or not.....

I'm looking for that post and will add it here if I can find it (unless someone else has it first).

 

[Fozda]

If you have continuity between the 2 green wires in the OBD2 port, you have a problem.
I messed that up on my build and spent a solid week or so trying to figure out what the problem was.

 

[escapepilot]

Pin 2 green here:

Goes to BCM green here:

 

[escapepilot]

and if memory is correct, all of those green wires come together near where the clutch and brake wires split from the main bundle.

 

[Gtstorey]

Post 72 would indicate some problems in the high speed data connections, if the test was done correctly. The green wires are low speed. There could be a problem with the low speed also, but I would focus on the high speed until that problem is worked out. It. Could be as simple as not making a good connection with a meter or needing to calibrate it.

Can someone with an LSJ confirm that they get 60 ohms on the high speed connection at the data link/obd2 port?