B1C1A
B1C1A-PASSENGER ACTIVE HEADREST CONTROL CIRCUIT OPEN
Special Tools:
For a complete wiring diagram, refer to the Wiring Information.
NOTE: If this code is setting on a Right Hand Drive Vehicle (RHD) follow the diagnostic procedure for (whatever the BXXXX-Driver Active Headrest Control Circuit Open).
Theory of Operation
The Passenger Active Headrest signal circuit is driven by a solenoid that also uses a diode in parallel. The single electrical component of the AHR (Active Headrest) unit is the latch-release solenoid. The solenoid is connected by a 2 way pigtail wire and harness connector. The pigtail wire and 2 way connector are routed through the center of one of the headrest support posts and down through the guide sleeve to the interior of the seat back, where it connects to the seat wire harness. The solenoid is grounded at an independent dedicated ground. The AHR components itself cannot be repaired. If damaged or ineffective, the AHR (Active Headrest) must be replaced as a new assembly. If upon inspection the AHR has deployed it can be reset following the proper reset method. Reset Procedure. Also if the already deployed Driver or Passenger AHR are latched in the locked position please see the scan tool miscellaneous functions to set the latch in the unlock or deployed position. Please be very observant and careful, the scan tool should never be used to actually deploy a known good non-deployed Driver or Passenger AHR.
- When Monitored:
The Occupant Restraint Controller (ORC) continuously communicates with the Passenger Active Head Restraint over the Passenger Active Head Restraint Solenoid Signal circuit. The Passenger Active Head Restraint communication and on board diagnostics are powered by the ORC signal. The ORC checks for a open condition every 10ms. The ORC checks the circuit both pre and post fault setting condition. This allows the ORC to de-mature a code in the same ignition cycle.
- Set Condition:
This code will set, if the ORC detects High voltage or an Open on the (R677) Passenger Active Head Restraint Solenoid Signal circuit.
1. VERIFY ACTIVE DTC
NOTE: Make sure the battery is fully charged.
1. Turn the ignition on.
2. With the scan tool, read the ORC DTCs.
Does the scan tool display active B1C1A-PASSENGER ACTIVE HEAD RESTRAINT CONTROL CIRCUIT OPEN DTC?
Yes
- Go To 2
No
- Perform the AIRBAG SYSTEM INTERMITTENT TEST. Initial Inspection and Diagnostic Overview.
2. CHECK FOR A SHORTED ACTIVE HEAD REST CIRCUIT IN PASSENGER ACTIVE HEAD REST
WARNING: Turn the ignition off disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
1. Access the Passenger Active Head Rest harness connector located in the passenger seatback jumper harness.
2. Disconnect the Passenger Active Headrest harness connectors.
NOTE: Check the connectors - Clean and repair as necessary.
NOTE: Please use the Active Head Rest Load Tool in testing the present status of the AHR signal circuit.
3. Connect the AHR Load Tool to the passenger AHR seatback jumper harness connector going into the seatback and under the seat.
WARNING: Turn the ignition on, then reconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
4. With the scan tool, read the active ORC DTCs.
Does the scan tool display: B1C1A-PASSENGER ACTIVE HEADREST CONTROL CIRCUIT OPEN?
Yes
- Go To 3
No
- WARNING: Turn the ignition off disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
- Replace the Passenger Active Head Rest. Active Head Restraint - Removal.
3. CHECK THE PASSENGER ACTIVE HEAD REST (Z908) GROUND CIRCUIT FOR AN OPEN
WARNING: Turn the ignition off disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
1. Measure the resistance of the (Z908) Ground circuit between the Driver Active Head Rest and ground.
Is the resistance below 5.0 Ohms?
Yes
- Go To 4
No
- Repair the Ground circuit for a open or high resistance.
- Perform the AIRBAG SYSTEM VERIFICATION TEST. Airbag System Verification Test.
4. CHECK THE (R677) PASSENGER HEAD RESTRAINT SOLENOID SIGNAL CIRCUIT FOR AN OPEN OR HIGH RESISTANCE (ACTIVE HEAD REST SEAT BACK JUMPER SIDE TO ORC MODULE)
1. Measure the resistance of the (R677) Passenger Active Head Restraint Solenoid Signal circuit between the Passenger Head Restraint harness connector and the appropriate terminal of the SRS Load Tool Adapter.
Is the resistance below 1 Ohm?
Yes
- Go To 5
No
- Repair the (R677) Passenger Active Head Restraint Solenoid Signal circuit in the seat back and body harness for an open or high resistance.
- Perform the AIRBAG SYSTEM VERIFICATION TEST. Airbag System Verification Test.
5. CHECK THE OPERATION OF THE PASSENGER ACTIVE HEAD RESTRAINT
1. Replace the Passenger Active Head Restraint.
2. Reconnect the vehicle body harness to the Passenger Active Head Restraint harness connector.
3. Remove any special tools or jumper wires and reconnect all previously disconnected components - except the Battery.
WARNING: Turn the ignition on, then reconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
4. Connect the scan tool to the Data Link Connector - use the most current software available.
5. Use the scan tool and erase the ORC stored codes.
6. Turn the Ignition Off and wait 15 seconds before turning the Ignition On.
7. Wait one minute and read active codes and if there are none present read the stored codes.
Does the scan tool display active B1C1A-PASSENGER ACTIVE HEADREST CONTROL CIRCUIT OPEN DTC?
Yes
- WARNING: Turn the ignition off, disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
- WARNING: If the Occupant Restraint Controller (ORC) is dropped at any time, it must be replaced. Failure to follow these instructions may result in possible serious or fatal injury.
- Replace the ORC.
- Perform the AIRBAG SYSTEM VERIFICATION TEST. Airbag System Verification Test.
No
- Repair is complete.
- Perform the AIRBAG SYSTEM VERIFICATION TEST. Airbag System Verification Test.