What am I missing
So We install a used transmission in this car and now it will not crank with the key. I can jump the relay and it will crank with no issues and start. So I go over the wiring diagrams double check the fuse box and all the connection and have not found any issues. ( the person that installed it no longer works for me) So seams simple enough Turn the key It tells BCM that the key is on that tells the ECM to power the crank relay. Scan data NO codes. NO security light codes and the light is off. Range sensor is showing it is in park and changes if shifted through the gears. Scan data shows key on and the command to start and turn on crank relay. I can unplug the ECM and jump the crank relay and it will crank. Looking like the ECM has failed. Or am I missing something.
I'm assuming it won't start in neutral as well? The range switch on that one is easy to get to, I'd probably try backprobing and making sure the signals were correct on it and make sure all grounds are good as well. (Best I recall, that trans has at least on major ground on bellhousing?
Verifying ECM signal to relay is simple enough. Ground for crank relay (pin 85) is supposed to be attached to transmission. Was it left unhooked? If everything is OK there, check the backside of underhood fuse block (they are common for failing at connections).
if I’m reading the wiring diagram for it. You can jump relay and it cranks. Scan data shows command. I would check signal at relay from pcm. Purple/white which will be 12v commanded. If it’s not there then check signal out of pcm at it. If still no output signal. Either your missing permission on scan data or pcm issue. If you do have it, obviously circuit fault- broken wire/ground Ect to relay
I agree with Mike check the grounds
I had a similar vehicle a few weeks ago with a no crank after the shop had replaced the clutch. On the main ground cable connection, on a transmission stud near the rad side, there was also a smaller diameter ground cable. The smaller ground cable was actually 3 small wires taped together. When I unwrapped the tape, one of the 3 small ground wires broke off from the terminal.
I agree with Brian Knapp—ill do alot verifications with scanner: check start permission, inputs and outputs related to permit starter operation...i wont be surprised that it needs to be programmed - so pcm recognizes and allow permissions.... —-Also try With scanner Turn on starter relay. Check Shifter Positions on scanner and on dash if match ok—might be out adjustment .
Remove relay and check pins in fuse box and see what is missing. Should have 2 grounds and 2 powers with key in crank position. I would check with test light. I have had no cranks before, after transmission replacement and usually it is a loose ground connection.
If it started and ran prior to your former employee touching it, then I'd be looking at things that could conceivably be screwed up on the install. Grounds are the #1 thing shops usually forget to check or verify after major work. The next thing I'd be looking at is potentially pinched or damaged harness. Specifically check g103,g107,g109,j101.
Not looking at any schematics after getting home from the class tonight, but I'm also for the grounds...or lack of them.Do I understand that the engine didn't start since it was installed? May have to open up the harness, hopefully wires weren't cut on the remove portion to save time. Also make sure pins aren't bent in the connectors at the trans. Feel free to give me a call !
I had a similar problem with a Trailblazer that we replaced a motor in.I small ground wire that was tacked up to the radiator core support and ran into the main wire loom had corrosion going about 3 inches up the wire.spliced a new wire and started right up.The starter relay gets its signal from the PCM so the PCM has to be grounded and that's what I think happened in…
There are a couple things I would check. First thing I am curious about is some scan data. That vehicle may or may not be Global A which could potentially cause a problem. For now though I would like to just check scan data. You should see a PID in ECM that says Crank Request or similar, this should read yes during key in the start position. If this PID reads NO then we have something…
So the plot thickens. I also had no injector pulse. This is what I got. Confirmed all power and grounds to the fuse block and PCM. Load test with a head lamp bulb. Inspected fuses and relays all are good. No security light issue. Comes on for bulb check and goes out. No alarm activation. In history Scan data shows Accs on, Also shows a start command and crank relay on when viewed in PCM when…
No injector pulse? Contradicts with sentence 2 on your original post.
No because it will not crank with the key and it ran before. New issue along with the original issue
If you believe the pcm was damaged then you need to absolutely recheck every single ground. #1 reason a pcm would fail after a simple engine or trans swap was failure to reconnect grounds.
Hi Robert: I'm confused. Nowhere did you mention programming the replacement module. If you didn't, why would you expect not to have a VIN mismatch? Guido
Before I tried to program the used PCM I had it plugged in and jumped the starter relay to see if I got my injector pulse back. I got injector pulse back so I then programmed the unit. Sorry for the confusion At my shop I have had no PCM issues like a lot of others do. Now as I sit back and go through everything that has happened it is a much clearer picture for me in my mind
So is this car fixed, just needed new PCM?
yes. The resolved button is gone at the top of the page
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I did a transmission on a 2012 chevy Orlando 2 days ago. May be similar set up as the HHR. Had the same kind of problem when I finished with a no crank situation. After wondering about vin ID ect... it turned out that I had forgot to install a ground wire that was held by the lower starter bolt when I had removed it to go back in and install the torque converter bolts that I had forgotten. (Yeah…