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SRS DTC Troubleshooting: 56-31

DTC 56-31:
 Lost Communication with the ECM/PCM (PGM-FI system)
  1. Turn the ignition switch to ON (II), then wait for 10 seconds.
Is DTC 56-31 indicated?
Go to Step 4 .
NO -
Intermittent failure, the system is OK at this time. Go to Troubleshooting Intermittent Failures. If another DTC is indicated, troubleshoot the DTC.
  1. Turn the ignition switch to ON (II), and see if the malfunction indicator lamp (MIL) comes on.
Does the MIL come on?
NO -
Go to Step 5 .
  1. Turn the ignition switch to LOCK (0).
  1. Install a jumper wire between the No. 16 and the No. 17 terminal of SRS unit connector A (39P).

  1. Check for continuity between the No. 3 and the No. 4 terminals of the ECM/PCM connector A (49P).
Is there continuity?
Faulty SRS unit or poor connection at SRS unit connector A (39P) and the SRS unit. Check the connection between the connector and the SRS unit. If the connection is OK, replace the SRS unit.
NO -
Open in the left engine compartment wire harness or the floor wire harness; replace the faulty harness.■