Just finishing up the LQ4 swap in my 71 C10 and I'm having issues getting the pedal to communicate with the t/b.
Getting the following codes:
P1125 - Accelerator Pedal Position (APP) System
P2120 - Throttle/Pedal Position Sensor/Switch ”D” Circuit
P2125 - Throttle/Pedal Position Sensor/Switch ”E” Circuit

Everything is out of an 05 2500HD except the TAC module which is out of an 06 Suburban 1500.

I checked the pins in the connectors(did have 1 apart to get wiring thru firewall) and they're all in tight and look to be solid.

I'm going to grab an ohmmeter on the way home to check for breaks in the harness but beyond that I dont know where to go.

Does anybody have any thoughts or input as to where to start?

 

Make sure the TACs are interchangable. From the codes it sounds like the gas pedal is bad. Try a known good gas pedal if you have another of can borrow one.

 

Thanks for the respons e- I googled the p/n on the TAC before I bought it and I think it said they were interchangable from 03-06. I'll double check though.

My wife has an 03 Tahoe, can pop the pedal out of it tonight really quick. I planned on doing that with the pedal and the TAC module just to check things out.

 

i pulled the TAC out of the wifes escalade and it fixed my issue. Beauty of having the wife drive your parts checker

 

Heck yes!
Where was the TAC located on your Escalade?

 

Stuck the TAC module out of wife's Tahoe on it and it's working as it should.
Easy fix.

 

03-05 tacs are interchangle able put that 06 up for sale again.

 

In looking at it closer I think it's opening at double speed - t/b is wide open at 1/2 throttle on pedal.
Tahoe has adjustable pedals whereas my pedal is not. I think there were 2 different TAC's used. I found 2 part #'s but can't tell what the difference between them is - 12573059 & 12588923.
Does anybody have any info on the difference between the 2?