RonnieBee

2006 Impala SS 5.3L -- 140,000+ miles -- Problem description: P2138 Throttle/Pedal Pos Sensor/Switch D / E Voltage Correlatio

According to online research, I don’t think the problem I describe first is related to current problem, but not sure. About 700 miles ago abs & traction control lights on & reduced engine power displayed, only when turning hard right. No codes that my reader could read. Took it to a shop I’ve done business with for 30 yrs. Their code reader showed right front speed sensor defective. The tire wiggle test showed wheel bearings to be worn. We replaced both front hubs. It didn’t fix the problem. We eventually found the green wire to sensor crimped about 4” from sensor. We cut, spliced, & soldered making the harness slightly longer. More than 600 miles later, traction control & check engine lights on, service traction control & engine power reduced displayed. Research pointed to throttle body or accelerator pedal. I inspected throttle body & found it to be pretty nasty. I took it off & cleaned it, reinstalled, cleared codes & everything seemed fine for 20 miles, then same thing again. Since cleaning seemed to have an effect, I assumed it was the problem. I bought a new throttle body, installed it & got 25 miles before problem returned. I then removed it & the accelerator pedal. I found help online for how to test all the parameters of each with a multi-meter set to ohms. All passed the tests. The 2 throttle bodies tested nearly the same. I checked & cleaned all the wire connections & re-installed everything (original throttle body back on). I got 9 perfect miles out of it before it started all over. Each time the reduced power message has displayed, it has still allowed me to travel at highway speeds. It just doesn’t accelerate very well. GM issued a service bulletin on this problem in 2007 that points to water intrusion from a leak into the body harness connection. I took interior trim off, but did not remove the harness. I found no evidence of water damage or corrosion. I’m stumped!