What is the correct connection for Pin 2 of a VAG/Audi COP? The connection is described as “signal ground” . I currently have it connected to a sensor ground pin on the EMU Black, but I’m seeing spikes in the sensor ground for several temperature sensors (CLT, oil, IAT). The spikes have roughly the same frequency as the ignition pulses at idle, leading me to suspect the COP wiring.
I understand that some COPs (Toyota) use the signal ground to send a pulse to the ECU to confirm successful firing, but other COPs use it as the reference ground for the trigger logic. I wired COP pin 2 to ECU sensor ground to provide a reference ground.
The COP is a Bosch 0 986 221 024.
Wiring is:
pin 1 - +12VDC on dedicated circuit
pin 2 - EMU Black sensor ground (B38)
pin 3 - ignition output from EMU Black
pin 4 - grounded directly to engine