Accelerator Pedal Position Sensor

[brs5156]

So I have a Saturn Aura 3.6L w/ ~130k miles

Every once in a while the "reduced engine power" warning was coming up on the dashboard and I was getting a P2125 code. I could turn the car off and turn it back on and the light would go out, but I wanted to remedy the problem so I decided to replace the accelerator pedal, and throttle body position sensor at the same time (hoping that this would fix it).

However, once I replaced the gas pedal immediately after I turned the car on to accessories I would get a P2127 code that I could not clear. After driving the car around the block a couple times the P2122 code popped up as well. I was a little annoyed because these were new codes so I plugged the original pedal back in, cleared the codes and drove the car w/ out the reduced engine power light coming back on, or any other codes popping up. I haven't driven it enough for the car to go through all of the readiness checks to see if I have any new codes, but does anyone know why I would/could be throwing a P2127 code w/ a brand new gas pedal and not the original?

Thanks,

[fdryer]

Drive by wire systems are enhancements to EFI systems using an electronic pedal and electrical throttle commanded by the ECM. Reduced power indication is a safety default to prevent any possibility of engine runaway, a software program when position sensors aren't detected as correct (two in throttle, two in pedal). While not familiar with Aura's, L300's have similar configurations. A low voltage reference is used for position sensors and may create unusual problems from damage to wiring, short circuit conditions, deteriorating electronics, corroded connections, etc.. Throttle, pedal and ECM are integrated and calibrated electronically for precision, doing away with linkages and binding. However, electronics presents it's own set of problems different from mechanical issues. The voltage reference needed for sensors may fail, wiring may suffer damage, connections corrode, and electronic parts wear. One set of problems eliminated may create a whole new set of problems unique to drive by wire systems. While the app sensor is replaceable, throttle sensors may require a calibration procedure. Not everything is plug n' play. Merely 'exercising' disconnect and reconnecting​ electrical parts can clean dirty connections. Low voltage signals are susceptible to wiring and terminal damage since these low voltages, <5v, carry zero current and rely on perfect connections. Reference voltage variances can introduce unusual problems complicating and confusing automated diagnostics. This can turn troubleshooting upside down with no rhyme or reason, clearing up on its own.

If error codes don't reappear after all readiness monitors pass, you may consider your repairs a learning experience in electrical/electronic nuances not discussed often. Hopefully this situation doesn't return.