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 (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Clear the DTC with the HDS.
Turn the ignition switch OFF, and then back ON (II).
Check for DTCs with the HDS.
Is DTC B1080 indicated?
1. YES - Go to step 4.
2. NO - Intermittent failure, check for loose or poor connections at the relay control module connector K (10P) and under-dash fuse/relay box connector D (17P). If the connections are OK, check the battery condition (see BATTERY TEST ) and the charging system.
Check the MICU IG1 power supply No. 21 (7.5 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
1. YES - Go to step 5.
2. NO - Replace the fuse and recheck for DTCs.
Measure voltage between the No. 8 terminal of the under-hood fuse/relay box connector K (10P) and body ground.

Fig 1: Measuring Voltage Between No. 8 Terminal Of Under-Hood Fuse/Relay Box Connector K (10P) & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 6.
2. NO - Open in the wire between the under-hood fuse/relay box and the under-dash fuse/relay box. Repair the wire and recheck for DTCs.
Check the voltage between the No. 10 terminal of the under-hood fuse/relay box connector K (10P) and body ground.

Fig 2: Checking Voltage Between No. 10 Terminal Of Under-Hood Fuse/Relay Box Connector K (10P) & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there less than 1 V?
1. YES - Faulty relay control module; replace the under-hood fuse/relay box.
2. NO - Open or loose connection in the wire between the under-hood fuse/relay box and G503, G601. If the wire is OK, inspect the G503 and G601.