Went into Low Engine Power mode

**LouF** · 08-11-2019

Took a drive to check my brakes, and I lost significant engine power.

I am seeing codes P0120, P0220, P0404, P1404, P1516 and P2101. I think I also saw an anti-lock brake system message.

Earlier that day, I replaced front brake pad guide hardware. I mistakenly jacked up the car on splash shield which pushed on the core support. It's bent, but there doesn't seem to be anything else wrong.

Any wiring harness I checked looked fine, vacuum lines look good...I am stumped.

Could a bad EGR be setting this all off? I had a similar low power mode when a vacuum tee broke.

Also, could a shorted wheel speed sensor be triggering a major electrical problem? I have had occasional anti-lock brake hiccups which had me contemplating looking at the wheel speed sensor wires.

**LouF** · 08-12-2019

Sorry, it is a 2005 GTP

**bandook** · 08-12-2019

By core support, do you mean the oil pan?

**Scottydoggs** · 08-12-2019

core support is up higher then the front sub frame, so im thinking he missed the frame and jacked it up via the core support and that can crush a radiator easy.

not sure if theres a harness under there you might have pinched, cause thats a load of codes.

if you clear the codes do they all come right back?

**LouF** · 08-12-2019

Yes, the front core support where the radiator is. There are no leaks from the radiator.

I cleared the codes, and only P1516 came back, immediately. I did not drive it, especially since it is at reduced power mode.

I don't believe there are any wire harnesses in the area. There is one that sits hon top of the frame, and it does not appear to be touched.

Also, I had a well experienced Grand Prix enthusiast agree that there isn't any wiring harness below the radiator. He did say there is one above the radiator, but I am not seeing it.

**Scottydoggs** · 08-12-2019

the one up top is tucked inside the support, if you take the dog bone mounts off the support you'll find it.

could be a bad wire at the plug for the tac. P1516 Chevrolet Throttle Actuator Control Module Throttle Actuator Position Performance: Code Meaning, Causes, Symptoms, & Tech Notes or its just went bad.

**LouF** · 08-12-2019

After resetting DTCs, it always has Reduced Engine Power, Traction Control Off and Service Traction System on the information center. P1516 (throttle actuator control position) is always there. P0120 (TPS circuit-A output voltage compared to circuit-B) and P0220 (PCM voltage) has reappeared once.

I took the splash shield off, and there does not appear to be any wiring. The large harness at the frame are (1) red and (1) black heavy gauge wires, untouched.

**LouF** · 08-12-2019

Originally Posted by Scottydoggs

the one up top is tucked inside the support, if you take the dog bone mounts off the support you'll find it.

OK, will go do.

**Scottydoggs** · 08-12-2019

dbw can suck, the pedal or the tb might have taken a crap here.

**LouF** · 08-12-2019

Originally Posted by LouF

OK, will go do.

There are no wiring harnesses high or low. I took out the fans and looked behind radiator and condenser coil to be absolutely sure - nothing. - cleaned lots of grit and grime from the radiator.

This must be some strange coincidence. I moved the car twice before going on this longer test drive when the malfunction occurred, so that can make sense.

**LouF** · 08-12-2019

Originally Posted by Scottydoggs

dbw can suck, the pedal or the tb might have taken a crap here.

Sounds possible (read these similar items in other research), but there are so many other parts mentioned. PCM faliure?

I checked the EGR and it is not stuck; unplugged and replugged the TB connector. Checked various wires for burn or wear since last week I got aggressive on solving an intermittent misfires - everything looks OK. Fuses in underhood fuse box look good. Battery is fully charged/assumed to be good.

**LouF** · 08-13-2019

Originally Posted by Scottydoggs

dbw can suck, the pedal or the tb might have taken a crap here.

Problem solved. It was a piece of tape that I used around the crankcase ventilation tube elbow at the snorkel that came off and got sucked into the airstream. LUCKILY, it got caught at the throttle plate, OMG. It was preventing the butterfly from going to closed/idle position. Removed it, cleaned the throttle body and did a quasi-relearn process, and back to a normal running engine. That threw everything off !

Thank you very much for your help!! - the final guess was right at where the issue was, the TPS/throttle body.

**bandook** · 08-13-2019

Nice! Scotty is like the rain man of the 3800. He's helped me a ton.

**LouF** · 08-14-2019

Thanks. Yes, I don't think I would have followed through with the TPS; I was sold on a failed PCM. I was about frantic thinking of all the parts that could have been thrown at it.

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