How to Troubleshoot Circuits at the PCM

How to Troubleshoot Circuits at the PCM

NOTE: The PCM overwrite data and monitors the EVAP system for up to 15 minutes after the ignition switch is turned OFF. Jumping the SCS line after turning the ignition switch OFF cancels this function. Disconnecting the PCM during this function, without jumping the SCS line first, can damage the PCM.

1. Jump the SCS line with the HDS.
2. Inspect the circuit on the PCM, according to the DTC Troubleshooting, with a commercially available digital multimeter, patch cords, and pin probes.





3. Remove the PCM cover (D), and disconnect PCM connectors.

NOTE: PCM connectors A, B, and C have symbols (A=[square], B=[circle], C=[triangle]) embossed on them for identification.





4. Check the connector inspection port (A) diameter, and select a suitable pin probe; a commercially available banana jack (Pomona Electronics Tool No. 3563 or equivalent).





5. Connect one side of the patch cord (A) terminal to a digital multimeter (B), and connect the other side of the patch cord terminals to the pin probe (C).
6. Gently slide the pin probe into the inspection port at the connector terminal side. Always use the inspection port. Do not slide the probe into the connector terminals.

NOTICE:
^ For accurate result, always use the pin probe.
^ To prevent damage to the connector terminals, do not insert test equipment probes, paper clips, or other substitutes as they can damage the terminals. Damaged terminals cause a poor connection and an incorrect measurement.
^ Do not puncture the insulation on a wire. Punctures can cause poor or intermittent electrical connections.