DTC B12D1: Power Control Unit IG1B Circuit Error

NOTE: 

• NOTE:  If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2015-17), or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2018-19) .

• Make sure aftermarket accessories are not installed.

DTC (Power Control Unit)

1. Problem verification

   -1. Clear the DTCs with the HDS.

   - 2. Turn the vehicle to the ON mode.

   - 3. Wait 10 seconds.

   - 4. Turn the vehicle to the OFF (LOCK) mode.

   - 5. Wait 5 seconds.

   - 6. Check for DTCs with the HDS.

   DTC Description	DTC
   B12D1 Power control unit IG1B circuit error

   Is DTC B12D1 indicated?

   YES 

   Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for loose or poor connections.

2. Determine possible failure area (IG1B relay circuit ON problem, IG1B relay circuit OFF problem)

   -1. Turn the vehicle to the ON mode.

   - 2. Check the parameter (s) below with the HDS.

   Signal	Current conditions
   	Value	Unit
   IG1B

   - 3. Check the IG1B with the HDS.

   Is there battery voltage?

   YES 

   Go to step 3.

   NO 

   Go to step 4.

3. Under-dash subrelay box test (IG1B relay circuit)

   -1. Do the under-dash subrelay box test (IG1B relay circuit).

   Is IG1B relay circuit OK?

   YES 

   Repair a short to power in the wire.

   NO 

   Faulty IG1B relay circuit, replace the under-dash subrelay box .

4. Under-dash subrelay box test (IG1B relay circuit)

   -1. Do the under-dash subrelay box test (IG1B relay circuit).

   Is IG1B relay circuit OK?

   YES 

   Repair an open or high resistance in the wire.

   NO 

   Faulty IG1B relay circuit, replace the under-dash subrelay box .