DTC B12D0: Power Control Unit IG1A Circuit Error

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 ChecksBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2 (without the HDS)Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not CommunicatingBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode C - No DTCs and Output Won't Shut OFFBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode D - No DTCs and Output Won't Turn ON .

NOTE:  Make sure aftermarket accessories are not installed.

• 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
  B12D0 Power control unit IG1A circuit error

  Is DTC B12D0 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 (IG1A relay circuit ON problem, IG1A 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
  IG1A

  3. Check the IG1A with the HDS.

  Is there battery voltage?

  YES 

  Go to step 3.

  NO 

  Go to step 4.

• 3. Under-dash subrelay box test (IG1A relay circuit):

  1. Do the under-dash subrelay box test (IG1A relay circuit) .

  Is IG1A relay circuit OK?

  YES 

  Repair a short to power in the wire.

  NO 

  Faulty IG1A relay circuit, replace the under-dash subrelay box .

• 4. Under-dash subrelay box test (IG1A relay circuit):

  1. Do the under-dash subrelay box test (IG1A relay circuit) .

  Is IG1A relay circuit OK?

  YES 

  Repair an open or high resistance in the wire.

  NO 

  Faulty IG1A relay circuit, replace the under-dash subrelay box .