I have a 2010 LR2 (gasoline) that has some electrical codes. I've replaced crank and cam position sensors, MAF and MAP sensors, the throttle body, and accelerator pedal. After most of these I thought I had it fixed but it keeps coming back. Current codes are P2138 for throttle/pedal position sensor and P0642 Sensor Reference Voltage A Circuit Low.

Some internet and AI searchs lead me to check the APP signals using an OBDII reader because it seems P2138 means the D and E signals don't match. Viewing live data for those two show that D is steady at about 7.1 and E fluctuates between 7.8 and 8.1. I read that they don't need to be exactly the same but should go up and down together so the fluctating is not good. That lead to replacing the gas pedal (which didn't fix it) and the throttle body (which didn't fix it).

Right now I'm wondering if the ECM is bad.





I found a manual online with some wiring diagrams. It shows the wires to the gas pedal labeled with what they are and their colors. Electronic Engine Controls (Sheet 2) — 2010 Land Rover LR2 (LF) L6-3.2L Service Manual | Operation CHARM (see above). I unplugged the pedal and checked voltages at each. Wire 1 was at 5.1 volts, wires 2 & 3 about 50 mV, wire 4 is ground and has continuity to ground, wires 5 & 6 had just under 12 volts. I know at least one wire should be about 5 volts for a signal but I don't know if these are correct. Does anyone know what each should read?

Any other suggestions of what to check or look at? I did see some threads mentioning alternators. Could a faulty alternator be the issue?