No Crank from Key

[phaetonman7]

So i am having an issue with a no crank from the key. when you turn the key on everything is working. The fuel pump primes and the dash lights up and the lock lights for a couple seconds and goes off. I was able to remove the crank relay and jump the circuit and it will crank and started. I checked the wire from the ignition switch to the bcm and that is good. i checked the wire from the ecm to the fuse panel and that is good. i have switched the brake switch connector and the clutch connector with no change. i removed the ignition switch and pulled it apart and it was clean inside ( i remember someone having an issue with that). I went through and checked that all the grounds are connected. It starts and runs fine when i jump the relay so that tells me that side of the circuit is fine. I am just not getting the signal from the ecm to the relay.

 

[Ross]

Have you pulled the codes from the OBDII port? Did you press the clutch? Is the clutch plugged into the correct electrical plug? (I think there are 2 plugs near it that fit.) If you follow my signature, you can update your signature, so that we won't have to ask: "What donor car do you have?"

 

[phaetonman7]

i have not checked codes yet. i was going to check them tonight when i get home. i did have the clutch in both the up and down position and neither made a change. i also changed the clutch and brake pedal plug and had no change. My donor is a 09 ss tc. i did the wiring harness myself just as an fyi.

 

[Ark :D]

1) Check and make sure the bolts in your fuse block are tightened as much as possible by hand.
2) Check continuity on the twisted data pair from the OBDII port all the way back to the ECM. Particularly if your fuel gauge doesn't read.

 

[Desert Sasqwatch]

GROUNDS. Many times a ground wire is not making good contact and that is what this one sounds like.

 

[phaetonman7]

Checked grounds all are connected. Checked clutch position in hp tuner and it is reading depressed and up as it should in the computer. ohm Checked wire from ecm to relay terminal for starter and that is good. Ohm Checked data wires in between ecm and bcm and those were reading good. Checked codes and only codes are ones that have to due with maf and boost sensors that are not plugged in. Ohm checked the wire from the ignition switch to the bcm and that was fine. Traced the whole wiring harness to check for a ground that I might of missed, all look to be connected. Like I said earlier, if I put the key in the on position and use a jumper wire on the starter relay it will crank and start up and stay running. I also swapped the starter relay with another one, no change. I checked all the fuses in the fuse box and bcm as well they are all good. I also checked the bolts in the fuse box and those are all tight.

 

[Ross]

I had a similar issue. My GM High speed LAN data was being intermittently transmitted.
I could start the engine if I turn the key on, and jump started the starter motor.
Replacing my power steering motor fixed my LAN data issue... but lots of reasons can stop the data from getting to the OBDII port.

 

[Gtstorey]

Is this not a symptom that the VATS security problem could cause?

 

[phaetonman7]

Well it ended up being the ground side of the relay. The wire comes out of the engine connector on the fuse panel and connects at the transmission bolt. It was connected but that wire was open. Ran another ground and it now starts with the key. Thanks for all ideas on what to look at.

 

[Desert Sasqwatch]

Uh huh!