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

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 10.

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 13
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 9.

NO -Go to step 7.
Turn the ignition switch to LOCK (0).
Check the No. 15(10 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?

YES -Repair an open or high resistance in the No. 15 (10 A) fuse circuit.

NO -Replace the fuse. If the fuse blows again, repair a short to ground on the No. 15 (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 32 And 37
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there less than 0.2 V?

YES -Go to step 10.

NO -Repair an open or high resistance in the ground wire(s) or poor ground (G401) and/or (G402).
Turn the ignition switch to LOCK (0).
Disconnect the immobilizer-keyless control unit 7P connector.
Disconnect the power window master switch 37P connector.
Check for continuity between power window master switch 37P connector terminals No. 33 and No. 35 and immobilizer-keyless control unit 7P connector terminals No. 3 and No. 4 respectively.

Fig 3: Checking Continuity Between Power Window Master Switch 37P Connector Terminals And Immobilizer-Keyless Control Unit 7P Connector Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -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(s) between the immobilizer-keyless control unit and the door multiplex control unit.