DTC U0199: Immobilizer-keyless Control Unit Lost Communication With Door Multiplex Control Unit

WARNING: This page is about a different car, the 2012 Honda Pilot. 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 ).

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 U0199 indicated?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. Check for loose or poor connections between the immobilizer-keyless control unit and the door multiplex control unit.
From the BODY ELECTRICAL SYSTEM SELECT menu, select B-CAN CONTROL UNITS INFORMATION, and then select CHECK CONNECTED CONTROL UNITS.
Is the power window unit detected?

YES -Go to step 9.

NO -Go to step 6.
Measure the voltage between body ground and power window master switch 37P connector terminal No. 13.

Fig 1: Measuring Voltage Between Body Ground And Power Window Master Switch 37P Connector Terminal No. 13
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 8.

NO -Go to step 7.
Check the No. 23 (10 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?

YES -Repair an open or high resistance in the No. 23 (10A)fuse circuit.

NO -Replace the fuse. If the fuse blows again, repair a short to ground in the No. 23(10 A) fuse circuit.
Measure the voltage between body ground and power window master switch 37P connector terminals No. 32 and No. 37 individually.

Fig 2: Measuring Voltage Between Body Ground And Power Window Master Switch 37P Connector Terminals No. 32 And 37
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there less than 0.2 V?

YES -Go to step 9.

NO -Repair an open or high resistance in the ground wire or poor ground (G401).
Turn the ignition switch to LOCK (0).
Disconnect the power window master switch 37P connector.
Disconnect the immobilizer-keyless control unit 7P connector.
Check for continuity between immobilizer-keyless control unit 7P connector terminals No. 3 and No. 4 and the power window master switch 37P connector terminals No. 33 and No. 35 respectively.

Fig 3: Checking Continuity Between Immobilizer-Keyless Control Unit 7P Connector Terminals No. 3 And 4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Faulty door multiplex control unit; replace the power window master switch (see REAR POWER WINDOW SWITCH TEST/REPLACEMENT ).

NO -Repair an open or poor connection in the B-CAN wire between the door multiplex control unit and the immobilizer-keyless control unit.