DTC B1080: Power Supply Circuit (IG1 Line) Input Error for Relay Control Module and MICU

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in 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 B1080 indicated?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. Check for loose or poor connections.
Turn the ignition switch to LOCK (0).
Disconnect under-hood fuse/relay box connector D (10P).
Turn the ignition switch to ON (II).
Measure the voltage between under-hood fuse/relay box connector D (10P) terminal No. 7 and body ground.

Fig 1: Measuring Voltage Between Connector D (10P) Terminal No. 7 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Substitute a known-good under-hood fuse/relay box and recheck.

NO -Go to step 9.
Turn the ignition switch to LOCK (0).
Check the No. 21 (7.5 A) fuse in the under-dash fuse relay box.
Is the fuse OK?

YES -Go to step 11.

NO -Replace the fuse. If the fuse blows again, repair a short to ground in the No. 21 (7.5 A) fuse circuit.
Disconnect under-dash fuse/relay box connector D (17P).
Connect under-dash fuse/relay box connector D (17P) terminal No. 6 and body ground with a jumper wire.

Fig 2: Connecting Connector D (17P) Terminal No. 6 And Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between under-hood fuse/relay box connector D (10P) terminal No. 7 and body ground.

Fig 3: Checking For Continuity Between Connector D (10P) Terminal No. 7 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Substitute a known-good under-dash fuse/relay box and recheck.

NO -Repair an open in the wire.