How to Troubleshoot Circuits at the ECM/PCM Connectors

NOTE: The ECM/PCM overwrites data and monitors the EVAP system for about 60 minutes after the ignition switch is turned to ACCESSORY (I) or to LOCK (0). Jumping the SCS line after turning the ignition switch to ACCESSORY (I) or to LOCK (0) cancels this function. Disconnecting the ECM/PCM during this function, without jumping the SCS line first, can damage the ECM/PCM.

Jump the SCS line with the HDS.
Disconnect ECM/PCM connectors A, B, and C.
NOTE: ECM/PCM connectors A, B, and C have symbols (A=□, B= , C=◦) embossed on them for identification.

Fig 1: Disconnecting ECM/PCM Connectors
Courtesy of AMERICAN HONDA MOTOR CO., INC.
When diagnosis/troubleshooting is done at the ECM/PCM connector, use the terminal test port (A) above the terminal you need to check.

Fig 2: Identifying Terminal Test Port
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Connect one side of the patch cord (A) terminals to a commercially available digital multimeter (B), and connect the other side of the patch cord terminals (C) to a commercially available banana jack (Pomona Electronics Tool No. 3563 or equivalent) (D).

Fig 3: Connecting Side Of Patch Cord Terminals To Commercially Digital Multimeter
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Gently insert the pin probe (male) at the test port from the terminal side. Do not force the tips into the terminals.
NOTE:
- For accurate results, always use the pin probe (male).
- 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.