I just made a bench harness for my HP tuner.
When I try and read the vehicle in hp tuners I get a message that says "detect protocol failed"
I have my bench harness wired so that there is no switch between 12V constant power and pin 19 keyed hot. Is this causing the problem?
I have it wired as such:
PCM:
1 GND
19 IGN (+12V)
20 +12V
57 +12V
58 Data to pin 2 on OBD2
OBD2 Port:
pin 16 12V
pin 4 and 5 ground
pin 2 data to 58 from pcm
can someone give me some insight?