DTC U0100: Gauge Control Module Lost Communication With ECM/PCM

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Clear the DTCs with the HDS.
Turn the ignition switch to LOCK (0) and then back to ON (II).
Wait for at least 6 seconds.
Check for DTCs with the HDS.
Is DTC U0100 indicated?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. Check for loose or poor connections.
Check for Fuel and Emission system DTCs with the HDS.
Are any DTCs indicated?

YES -Go to the INDICATED DTC'S TROUBLESHOOTING , then recheck.

NO -Go to step 6.
Turn the ignition switch to LOCK (0).
Disconnect the gauge control module 32P connector.
Jump the SCS line with the HDS.
Disconnect ECM/PCM connector A (49P).
Check for continuity between gauge control module 32P connector terminals No. 19 and No. 20 and ECM/PCM connector A (44P) terminals No. 36 and No. 37 individually.

Fig 1: Checking Continuity Between Gauge Control Module 32P Connector Terminals No. 19 And No. 20 And ECM/PCM Connector A (44P) Terminals No. 36 And No. 37
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Update the ECM/PCM if it does not have the latest software (see ELD REPLACEMENT ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), and recheck. If the indication goes away, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ). If the DTC is still present, replace the gauge control module (see GAUGE CONTROL MODULE REPLACEMENT ).

NO -Repair an open or high resistance in the wire.