B1C18
B1C18-PASSENGER ACTIVE HEADREST CONTROL CIRCUIT LOW
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) monitors the Passenger Active Headrest during the start up phase of the ORC module. The Passenger Active Headrest communication and on board diagnostics are powered by the ORC signal.
- Set Condition:
This code will set, if the ORC detects low voltage on the (R677) Active Head Restraint 1st Row Passenger Signal circuit.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Restraints System Pre-Diagnostic Procedure.
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 B1C18-PASSENGER ACTIVE HEADREST CONTROL CIRCUIT LOW DTC?
Yes
- Go To 2
No
- Perform the RESTRAINTS SYSTEM INTERMITTENT TEST. Restraints System Intermittent Condition Test.
2. CHECK THE (R677) ACTIVE HEAD RESTRAINT 1ST ROW PASSENGER SIGNAL CIRCUIT HARNESS FOR A SHORT TO GROUND
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 Headrest connector located in the passenger seat back.
2. Disconnect the Passenger Active Headrest harness connector.
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.
Does the scan tool display active B1C19-PASSENGER ACTIVE HEADREST CONTROL CIRCUIT HIGH?
Yes
- Turn the Ignition off.
- 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.
- Connect the Passenger Active Headrest harness connector. 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.
- Wait 15 seconds before turning the Ignition On.
- Use the scan tool and erase the ORC stored codes.
- Turn the Ignition Off, and wait 15 seconds before turning the Ignition On.
- Wait one minute and read active codes.
- If the B1C18-Passenger Active Headrest Control Circuit Low DTC becomes active, replace the Passenger Active Headrest. Headrest - Removal.
No
- Go To 3
3. CHECK THE (R677) ACTIVE HEAD RESTRAINT 1ST ROW PASSENGER SIGNAL CIRCUIT FOR A SHORT TO GROUND IN THE PASSENGER ACTIVE HEAD REST SEAT BACK JUMPER HARNESS
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.
NOTE: Inspect for damaged or bent terminals at the C315 underseat jumper harness connector.
1. Disconnect the C315 underseat harness connector.
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.
Does the scan tool display active B1C19-PASSENGER ACTIVE HEADREST CONTROL CIRCUIT HIGH?
Yes
- Repair the short to ground in the (R677) Active Head Restraint 1st Row Passenger Signal circuit between the C315 underseat harness connector and the Passenger Active Headrest harness connector in the seat back.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.
No
- Go To 4
4. CHECK THE (R677) ACTIVE HEAD RESTRAINT 1ST ROW PASSENGER SIGNAL CIRCUIT HARNESS FOR SHORT TO GROUND IN THE BODY HARNESS
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 Occupant Restraint Controller Module in the center stack area just below the radio.
2. Disconnect the ORC Module C2 connector.
3. Connect the SRS Load Tool Adapter 8443-28.
4. Keep the C315 underseat jumper harness connector disconnected.
5. Measure the resistance between ground and the (R677) Active Head Restraint 1st Row Passenger Signal circuit at the appropriate terminal of the SRS Load Tool Adaptor 8443-28.
Is the resistance below 5.0 Ohms?
Yes
- Repair the short to ground in the (R677) Active Head Restraint 1st Row Passenger Signal circuit located between the C315 underseat jumper harness connector and the ORC.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.
No
- Go To 5
5. CHECK OPERATION OF THE PASSENGER ACTIVE HEAD REST
1. Reconnect any previously disconnected harness connectors.
2. 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.
3. Connect the scan tool to the Data Link Connector - use the most current software available.
4. Use the scan tool and erase the ORC stored codes.
5. Turn the Ignition Off and wait 15 seconds before turning the Ignition On.
6. Wait one minute and read active codes and if there are none present read the stored codes.
Does the scan tool display active B1C18-PASSENGER ACTIVE HEADREST CONTROL CIRCUIT LOW 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 Occupant Restraint Controller (ORC). Occupant Restraint Controller - Removal.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.
No
- Repair is complete. Verify reconnecting of all components and inlines.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.