V1 First Start - no crank condition...

[Christopher Sanchez]

my Fuel pump cycled everything came on but a scan tool showed faulty clutch position sensor so I would check your wire from pcm

 

[ctuinstra]

We first had our clutch and brake switch harness swapped around, yes they are the exact same connector. But not pressing the clutch nor the brake and the car would start. If you tried to do it safely like you are supposed to and push in the clutch and the brake, it would not crank. Yep, something to make sure it's correct.

 

[Christopher Sanchez]

The relay click he is hearing is from the brake 3rd light that were on the coupes so I’m guessing his connectors are correct. The 5v reference that I cut that goes to the clutch position sensor is pin 14 on your pcm plug should be gray I’d check if you cut it. Only speaking from my own f ups

 

[Briann1177]

When I thinned my harness somehow I cut the clutch position sensor at the pcm plug. Apparently others have came close to doing the same so idk if the videos have a misleading step when doing a Turbo kit..

That's because the clutch pedal low reference signal is spliced with the fuel tank pressure sensor. If you're not paying attention, you can easily cut that entire wire out when thinning out the evap system. This almost got me too.

The videos don't address this since they are for an NA build.

 

[Astraeus]

You said is has 9.6v (which is a very odd voltage). Did you measure that using frame ground or 85 on the relay? Can you tell if that relay even clicks?

From everything else you said, everything seems to be fine, especially with the date lines. We need to focus on why that relay is that way.

It reads 9.6v to both frame ground and pin 85.

 

[Briann1177]

I noticed you're talking about the gray wire. That one is also spliced with the fuel tank pressure sensor and clutch pedal. So I would check both the tan and gray wires in your clutch pedal connector to ensure they have continuity.

 

[Astraeus]

I noticed you're talking about the gray wire. That one is also spliced with the fuel tank pressure sensor and clutch pedal. So I would check both the tan and gray wires in your clutch pedal connector to ensure they have continuity.

All 3 clutch position sensor wires have continuity to the proper pins on the ECM X2 connector:
Tan > Pin 9
Light Green > Pin 37
Gray > Pin 14

 

[ctuinstra]

It reads 9.6v to both frame ground and pin 85.

That is really odd.... You shouldn't see anything hardly when it's not activated. And 9.6 on it is not enough to excite the coil to activate it. You may want to trace it back to the ECM and verify that is what is coming out of the ECM.

 

[Astraeus]

That is really odd.... You shouldn't see anything hardly when it's not activated. And 9.6 on it is not enough to excite the coil to activate it. You may want to trace it back to the ECM and verify that is what is coming out of the ECM.

I don't have anything small enough to go in the pin from the backside of the ECM connector. It's a single continuous wire from the ECM plug all the way to pin 86. Other pins in the area read battery voltage.

I can't think of any other reason why this specific ECM output is 9.6v when everything is 5v or battery voltage, other than the ECM being bad. My scan tool couldn't connect to the car before hand. Anything else you can think of to try, or should I try replacing the ECM?

 

[Briann1177]

I agree that 9.6V is an odd voltage; however, it doesn't automatically mean the ECM is bad or that there is even a problem at all. I've seen weird voltages before on circuits that I thought I were having an issue with, but that ended up being nothing. Not everything in the overall circuitry is either 12V or 5V. Don't get too hung up on the 9.6V being your problem. It is interesting though.

Dumb question. Have you tried swapping that relay?

 

[Astraeus]

I agree that 9.6V is an odd voltage; however, it doesn't automatically mean the ECM is bad or that there is even a problem at all. I've seen weird voltages before on circuits that I thought I were having an issue with, but that ended up being nothing. Not everything in the overall circuitry is either 12V or 5V. Don't get too hung up on the 9.6V being your problem. It is interesting though.

Dumb question. Have you tried swapping that relay?

Hey, it's a good idea. Unfortunately the relay actuates when supplied battery voltage, and swapping the relay has no effect.

 

[Lonny]

It is too bad your not closer to Texas we could swap out components until we figure it out.

If you want to pull your harness and pack it up with the rest of your electronics we can fix it and send it back to you.

Or you can come visit and bring your goblin.

 

[ctuinstra]

I have a spare P12 ECM but I don’t know what car you have and it it takes the same ECM. Also not sure about if the BCM will accept it and allow it to start. Anyone?

 

[Astraeus]

If you want to pull your harness and pack it up with the rest of your electronics we can fix it and send it back to you.

I might take you up on this if I can't figure it out here pretty soon.

I have a spare P12 ECM but I don’t know what car you have and it it takes the same ECM. Also not sure about if the BCM will accept it and allow it to start. Anyone?

It's an 09 SS/TC. I just bought an ECM on eBay and some key blanks on Amazon. Appreciate the offer though. Hopefully the procedure here to erase and reset the keys will work (and the car starts). I'll keep trying things until the ECM shows up.

 

[Lonny]

If you swap to a different ECM you just need to install it, turn on the key and then wait ten minutes until the security light goes out. Repeat this step three times.
After the third time, when you turn the key on the security light should turn off after a few seconds and stay off.

If you have any questions give me a call.
Cell # 214-334-0232

 

[Briann1177]

The part that gets me is that the car started just fine before the tear down. I wouldn't imagine that an ECM would just die like that between tear down and restart. But it sounds like you've done a great job with your due diligence. There's not really much to the starting circuits so maybe it is an issue with the ECM.

I have the exact same donor, and I've been thinking back on my build and digging through the service manuals, but I can't really come up with much. Please keep us posted on what you find out.

 

[Briann1177]

This could very well be a red herring, but you mentioned that your OBD-II device wasn't communicating? I wonder if it's just a simple power issue or if there is something going on with the high/low speed data lines. But you also mentioned the gauges light up and the fuel pump comes alive so I really don't know.

I am still curious if you're getting codes or not, but I guess we won't know until you resolve that.

 

[Astraeus]

So after Lonny's reply, I called him. My security light does not shut off after a few seconds. He recommended I turn the key on and wait 10 minutes for the light to go off and reset the key. My car does not do this, the light stays on all the time, so it sounds like there is an issue with the key not providing the computer the correct code, and it doesn't seem to want to reset. I have checked the key reader around the ignition and it has the proper battery and ignition voltage, ground, and continuity with the BCM. My code reader still gives an error when trying to connect to the ECM. I checked the low-speed GMLAN wires, and those all seem to be good as well. Lonny suggested I check the polarity of the high-speed wires, which I will do later tonight.

 

[Briann1177]

I have a feeling you've already done this, but have you checked the theft deterrent module connections? Should have two power pins, a ground, and a green low speed data wire.

 

[Astraeus]

I have a feeling you've already done this, but have you checked the theft deterrent module connections? Should have two power pins, a ground, and a green low speed data wire.

Yep, I called it the key reader in the above post, but yes I checked all those and everything was good.