DTC B10CF: Left Daytime Running Lights Circuit Malfunction

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 ).
Make sure the No. 15(10 A) fuse in the driver's under-dash fuse/relay box is OK.

Clear the DTCs with the HDS.
Turn the ignition switch to LOCK (0).
Release the parking brake lever.
Turn the headlight switch OFF.
Turn the ignition switch to ON (II).
Is DTC B10CF indicated?

YES -Go to step 6.

NO -Intermittent failure, the system is OK at this time. Check for loose or poor connections.
Turn the headlight high beam ON.
Does the left headlight (high beam) come on?

YES -Go to step 7.

NO -Go to step 9.
Turn the ignition switch to LOCK (0).
Measure the voltage between body ground and driver's under-dash fuse/relay box connector Q (20P) terminals No. 1 and No. 2, and between body ground and driver's under-dash fuse/relay box connector R (24P) terminals No. 2 and No. 5 individually.
DRIVER'S UNDER-DASH FUSE/RELAY BOX CONNECTOR Q (20P)

Fig 1: Identifying Driver'S Under-Dash Fuse/Relay Box Connector Q (20P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

DRIVERS UNDER-DASH FUSE/RELAY BOX CONNECTOR R (24P)

Fig 2: Identifying Drivers Under-Dash Fuse/Relay Box Connector R (24P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there 0.2 V or less?

YES -Faulty driver's MICU; replace the driver's under-dash fuse/relay box, USA models (see DRIVER'S UNDER-DASH FUSE/RELAY BOX (MICU)REMOVAL AND INSTALLATION ), Canada models (see SPECIAL TOOLS REQUIRED ).

NO -Repair an open in the wire or poor ground (G501, G502).
Turn the ignition switch to LOCK (0).
Turn the headlight switch OFF.
Check the No. 28 (10 A) fuse in the driver's under-dash fuse/relay box.
Is the fuse OK?

YES -Go to step 12.

NO -Replace the fuse. If the fuse is blows again, repair a short to ground on the No. 28 (10 A) fuse circuit.
Check the left headlight bulb.
Is the bulb OK?

YES -Go to step 13.

NO -Replace the bulb and recheck.
Disconnect driver's under-dash fuse/relay box connector F (33P).
Disconnect the left headlight (high beam) 2P connector.
Check for continuity between driver's under-dash fuse/relay box connector F (33P) terminal No. 13 and left headlight (high beam) 2P connector terminal No. 2.
LEFT HEADLIGHT (HIGH BEAM) 2P CONNECTOR

Fig 3: Identifying Left Headlight (High Beam) 2P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 16.

NO -Repair an open or high resistance in the wire.
Check for continuity between left headlight (high beam) 2P connector terminal No. 1 and body ground.
LEFT HEADLIGHT (HIGH BEAM) 2P CONNECTOR

Fig 4: Identifying Left Headlight (High Beam) 2P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Faulty driver's MICU; replace the driver's under-dash fuse/relay box, USA models (see DRIVER'S UNDER-DASH FUSE/RELAY BOX (MICU)REMOVAL AND INSTALLATION ), Canada models (see SPECIAL TOOLS REQUIRED ).

NO -Repair an open or high resistance in the wire or poor ground (G302).