Reduced Engine Power, codes P1120, P1221, P1515, P1516

Tiny
JAREDHAXTON
  • MEMBER
  • 2002 CADILLAC ESCALADE
  • 6.0L
  • V8
  • 4WD
  • AUTOMATIC
  • 135,000 MILES
Got a code party on my hands here! I will lay out all of the codes below but for starters, The vehicle goes into REP mode pretty much every morning that it is below 50 degrees Fahrenheit. Sometimes it will even do it driving down the highway in warm weather but that is pretty rare. Once the car warms up for 10 minutes or so in the morning, you can turn it off, and back on, and should be able to finish the day without it happening again. Then restart the process the next day. Been hobbling along like this for about a year and a half now! Hopefully haven't done permanent damage! :/

So the codes with verbiage.

P1120 Throttle Position Sensor "A" Circuit

P1221 Throttle Position Sensor "A/B" Range/Performance

P1515 Command vs. Actual Throttle Position Correlation (PCM) Error

P1516 Command vs. Actual Throttle Position Correlation (TAC Module) Error

I replaced the TPS about a year ago trying to fix the problem and it didn't do anything. I am looking at used TAC modules for $160 or so but don't want to buy it if it isn't the problem. I am not well-versed in wiring but I own a multimeter. Would just need a small amount of coaching such as "Set it to DC 20v and put probes here and here".

I am hoping that this symphony of codes will point to something specific for a trained eye! Any thoughts? Next steps of troubleshooting? Thank you for your help!
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Sunday, April 18th, 2021 AT 5:24 PM

3 Replies

Tiny
NICKOLAOSF
  • EXPERT
Hi jaredhaxton,

we can help with that. It sounds you have a limp mode first start with code p1120
see below procedure.
All codes have to do with throttle position sensor, check wiring harness to throttle position sensor. After clear codes and run to verify if codes return.
Let us know what happens and please upload pictures or videos of the problem.
I am glad to help you, If there is anything else we can help you with please contact us again. Thank you for choosing 2CarPros.

Cheers, Nick
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Sunday, April 18th, 2021 AT 8:45 PM
Tiny
JAREDHAXTON
  • MEMBER
Just to update everyone, I hobbled the vehicle along through a few winters and finally decided to pay whatever money it took (within reason) to fix it in lieu of buying a new or newer vehicle. The problem was the throttle body itself. GM no longer made the part and there appeared to be maybe 1 remanufactured unit in all of the US. Lots of sites pretended to have it but once I paid for it, they would report back that it was not in stock.

O'reilly had one and I had to pay extra shipping on top of the $439.00 to get it. My mechanic swapped it out and it hasn't had the problem since. Winter is coming, but I'm not afraid anymore!
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Saturday, January 15th, 2022 AT 9:18 PM
Tiny
SEAN M
  • EXPERT
Thank you so very much for sharing the solution.

I am sure it will be helpful for anyone else who might be experiencing the same issue.
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Tuesday, January 18th, 2022 AT 9:05 PM

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