Ok disconnect the PCM and with an ohm meter test thes SCI transmit wire at
the data link connector for a short to ground if the resistance is below 5
ohms repair that wire for a short to ground. if it is not shorted to ground
test the SCI recieve wire at the data link connector for a short to ground.
If that wire is not shorted to ground check the SCI transmit and recieve
wire from the PCM to the data link connector for resistance. assuming that
those wires are not broken or shorted to ground the PCM is no good
sci recieve data link pin 6
sci transmit data link pin 7
sci recieve PCM connector pin 75 LG
sci transmit PCM connector pin 65 PK
Yes, there is definitely resistance (10-14 ohms) from pin 7 and ground while
both PCM connectors amd the TCM connectors are unplugged.
PCM pin 65 is bridged to TCM pin 7 supposedly at S154 (engine harness in
headlamp breakout). This connection is suspect.
Do you know where S154 is actually located? I would like to check that before
cutting and splicing in new wiring from PCM pin 65, TCM pin 7, and pin 7 at the
What do you think?
Really, thanks for all the help to date.
I could not find the splice and didn't want to unravel the harness (ugh). I cut
and spliced in new 18g wires at the connectors to the TCM , and PCM and then
ran a new wire through the firewall (via the hood cable grommet) to the ODBII
connector. Bingo, it now works! Scans every time.
Thanks for all you help.
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