DTC U0100: F-CAN Lost communication with PCM

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

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 ).
Check the vehicle battery condition first (see BATTERY TEST ).

Connect the HDS to the DLC (see General Troubleshooting Information .
Turn the ignition switch to LOCK (0), and then back to ON (II).
Check for DTCs with the HDS and DTC log data in the navigation system diagnostic mode (see SYSTEM DIAGNOSTIC MODE ).
Is DTC U0100 indicated with HDS and on the navigation display?

YES -Go to step 4.

NO -Intermittent failure. F-CAN communication line is OK at this time. Check for poor connections or loose terminals at the AcuraLink control unit (XM receiver).
Turn the ignition switch to LOCK (0).
Jump the SCS line with the HDS.
Disconnect AcuraLink control unit (XM receiver) connector A (32P) and PCM connector A (49P).
Check for continuity between AcuraLink control unit (XM receiver) connector A (32P) terminals No. 6 and No. 7 and PCM connector A (49P) terminals No. 49 and No. 48 respectively.

Fig 1: Checking Continuity Between Connector A (32P) And Connector A (49P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Check for poor connections or loose terminals at the AcuraLink control unit (XM receiver). If all connections are OK, update the AcuraLink control unit (see AcuraLink Control Unit Update ) if it does not have the latest software, and recheck. If the software is the latest, replace the AcuraLink control unit (XM receiver) (see ACURALINK CONTROL UNIT (XM RECEIVER) REMOVAL/INSTALLATION ).

NO -Repair an open in the wire between the AcuraLink control unit (XM receiver) and the PCM.