DTC U0100: Gauge Control Module Lost Communication With 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), or press the engine start/stop button to select the OFF mode and then the ON mode.
Start and run the engine for at least 5 seconds, then turn the engine off.
Check for DTCs with the HDS.
Is DTC U0100 indicated?

YES -Go to step 5.

NO -Intermittent failure, the F-CAN communication line is OK at this time. Check for DTCs in the PCM with the HDS. If F-CAN DTCs are present, check for loose or poor connections at the gauge control module and the PCM. If the connections are good, check the battery condition (see BATTERY TEST ) and the charging system, then clear all DTCs.
Check for DTCs in the PCM with the HDS.
Are any DTCs indicated?

YES -Go to the PCM indicated DTCS TROUBLESHOOTING , then recheck.

NO -Go to step 6.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
Jump the SCS line with the HDS.
Disconnect PCM connector A (49P).
Disconnect gauge control module connector A (32P).
Check for continuity between gauge control module connector A (32P) terminals No. 13 and No. 14 and PCM connector A (49P) terminals No. 49 and No. 48 respectively.

Fig 1: Checking For Continuity Between Gauge Control Module Connector A (32P) Terminals No. 13 And No. 14 And PCM Connector A (49P) Terminals No. 49 And No. 48
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Substitute a known-good PCM (see PCM REPLACEMENT ), and recheck. If the indication goes away, replace the original PCM. If the DTC is still present, replace the gauge control module (see GAUGE CONTROL MODULE REPLACEMENT ).

NO -Repair an open or poor connection in the F-CAN wire(s) between the PCM and the gauge control module.