Bad PCM?

[MrPuffels]

I have a 2009 mustang gt that I installed an On3 turbo in back in December. It ran great until about two weeks ago where the electronic throttle control light keeps coming on and puts the car into limp mode. I also get codes P0102, P0010, P2008, and P2107. I have replaced the tps and throttle body motor and no dice. I think I have narrowed it down to either wiring or the PCM. I get 12v, 5v, and ground to my maf for code P0102 and I have 12v to my solenoid for code P2008, so I'm inclined to say its not wiring but I'm not sure. Is there anything I'm missing? Or should I just bite the bullet and replace the PCM.

 

[Jonas1ne]

I wouldn't replace the PCM yet. Those codes point more toward a shared wiring, ground, or power issue than a failed PCM. Since the turbo kit has been on for a while, I'd inspect the harness around the turbo for heat damage, check all engine grounds, and do continuity tests from the affected components back to the PCM. Just because you have 12V, 5V, and ground doesn't rule out a wiring fault. I'd exhaust those checks before buying a PCM.

 

[86GT351]

I have a 2009 mustang gt that I installed an On3 turbo in back in December. It ran great until about two weeks ago where the electronic throttle control light keeps coming on and puts the car into limp mode. I also get codes P0102, P0010, P2008, and P2107. I have replaced the tps and throttle body motor and no dice. I think I have narrowed it down to either wiring or the PCM. I get 12v, 5v, and ground to my maf for code P0102 and I have 12v to my solenoid for code P2008, so I'm inclined to say its not wiring but I'm not sure. Is there anything I'm missing? Or should I just bite the bullet and replace the PCM.

Have you done any "Wiggle" testing at the connectors to the items related to the codes? Clear codes. With the car running, wiggle thr individual connectors and see if there is a wiring issue.

 

[Laga]

Check the ground on top of front support next to passenger side radiator support. The wires tend to corrode entering eyelet. Do you have 5V at TBPS and fuel pressure sensor? I am in process of replacing ECM right now. I lost 5V going to MAF. Lito has never heard of this. There is mention of it online. If you do need ECM replacement, avoid Module Experts. They have a 1/2 star rating everywhere, including BBB. I went with Flagship. Where ever you decide. Make sure they offer warranty.

 

[MrPuffels]

Have you done any "Wiggle" testing at the connectors to the items related to the codes? Clear codes. With the car running, wiggle thr individual connectors and see if there is a wiring issue.

The light only comes on when I begin to accelerate and the engine codes only come on once every 3 to 4 times the electronic throttle control light comes on so at idle is fine. Either way i wiggled every wire I could even if it was unrelated and its still idling perfect.

 

[MrPuffels]

Check the ground on top of front support next to passenger side radiator support. The wires tend to corrode entering eyelet. Do you have 5V at TBPS and fuel pressure sensor? I am in process of replacing ECM right now. I lost 5V going to MAF. Lito has never heard of this. There is mention of it online. If you do need ECM replacement, avoid Module Experts. They have a 1/2 star rating everywhere, including BBB. I went with Flagship. Where ever you decide. Make sure they offer warranty.

I do have 5v going to both but I have 10 ohms of resistance from the negative terminal on the battery to the ground next to the radiator that must be it I guess, but I have no clue where the grounds are on this thing

 

[JC SSP]

https://www.s197forum.com/threads/ground-wiring-locations.142010/

 

[MrPuffels]

I wouldn't replace the PCM yet. Those codes point more toward a shared wiring, ground, or power issue than a failed PCM. Since the turbo kit has been on for a while, I'd inspect the harness around the turbo for heat damage, check all engine grounds, and do continuity tests from the affected components back to the PCM. Just because you have 12V, 5V, and ground doesn't rule out a wiring fault. I'd exhaust those checks before buying a PCM.

There aren't any wires running by the turbo and I have everything heat wrapped but I do get like 20 ohms from the negatvie terminal on the battery to the engine block so it probably is a bad ground. Do you know where the grounds are? I only know of the one at the top of the firewall.

 

[MrPuffels]

https://www.s197forum.com/threads/ground-wiring-locations.142010/

Perfect thank you

 

[TexasBlownV8]

You have two grounds to the engine. Should definitely NOT be 10 or 20 ohms! ..should be close to 0.
Big ground on passenger side to motor mount stud/bolt; small strap ground behind driver's side head to body at front cowl area.
Make sure they are snug and clean.