B1B7A
B1B7A-PASSENGER SEAT WEIGHT SENSOR 3 - LEFT FRONT INPUT CIRCUIT HIGHB1B7A - Passenger Seat Weight Sensor 3 - Left Front Input Circuit High:
WHEN MONITORED
While the CAN bus ignition status is in IGN_RUN, the module checks the sensor input ranges.
SET CONDITION
If the module detects that the sensor input is greater than 96 ± 0.6% of the (R701) Seat Weight Sensor 5 Volt circuit voltage. Note that this DTC will remain active after the condition that set this fault is no longer present. Performing the Occupant Classification Module System Verification Test will change the status from active to stored if the condition that set the fault is no longer present.
POSSIBLE CAUSES
- Passenger seat harness improperly routed
- Passenger seat harness wires chafed, pierced, pinched, partially broken
- Passenger seat harness connector terminals broken, bent pushed out, spread, corroded, contaminated
- (R717) LT-FT seat weight sensor signal circuit shorted to voltage
- (R717) LT-FT seat weight sensor signal circuit shorted to (R701) seat weight sensor 5 volt circuit
- (R728) Seat weight sensor ground circuit open
- Left-front seat weight sensor
- Occupant classification module (OCM)
Diagnostic Test
1. CHECK FOR ACTIVE INTERNAL FAULTS, IGNITION FAULTS, AND BATTERY FAULTS IN THE OCCUPANT CLASSIFICATION MODULE (OCM)
NOTE:
- Ensure that the battery is fully charged.
- When reconnecting airbag system components, the ignition must be turned off and the battery must be disconnected.
Turn the ignition on, then off, and then on again.
With the scan tool, read Occupant Classification Module (OCM) DTCs.
Q: Does the scan tool display any active DTCs relating to internal faults, ignition faults, or battery faults?
YES: Diagnose and repair the DTCs. Refer to complete list of symptoms.
NO: Go To 2
2. VERIFY THAT DTC B1B7A-PASSENGER SEAT WEIGHT SENSOR 3 - LEFT FRONT INPUT CIRCUIT HIGH IS ACTIVE
NOTE: Failure to follow test instructions or aborting the test will cause faults to set when performing the Occupant Classification Module System Verification Test. To prevent faults due to process errors: Verify That All Tests Steps That Led You Here Were Performed As Directed; Verify That The Ignition Is In Run; Wait 30 Seconds After Changing The Seat Weight Before Proceeding To Allow The System To Stabilize; Only Press Scan Tool Buttons When Directed To Do So; and Perform The OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST To Completion. Occupant Classification Module (OCM) System Verification Test
With the scan tool in OCM, select More Options, select System Tests, and select Occupant Classification Module System Verification Test. Run the test by following the instructions displayed on the scan tool. When the test is complete, wait two minutes, and then proceed as follows.
With the scan tool, read OCM DTCs.
Q: Does the scan tool display active: B1B7A-PASSENGER SEAT WEIGHT SENSOR 3 - LEFT FRONT INPUT CIRCUIT HIGH?
YES: Go To 3
NO: Go To 9
3. VERIFY THAT DTC B1B7A-PASSENGER SEAT WEIGHT SENSOR 3 - LEFT FRONT INPUT CIRCUIT HIGH IS ACTIVE
WARNING: TO AVOID PERSONAL INJURY OR DEATH, TURN THE IGNITION OFF, DISCONNECT THE BATTERY AND WAIT TWO MINUTES BEFORE PROCEEDING.
Verify that all of the Seat Weight Sensor mounting screws are torqued to specification.
WARNING: TO AVOID PERSONAL INJURY OR DEATH, TURN THE IGNITION ON, THEN RECONNECT THE BATTERY.
NOTE: Failure to follow test instructions or aborting the test will cause faults to set when performing the Occupant Classification Module System Verification Test. To prevent faults due to process errors: Verify That All Tests Steps That Led You Here Were Performed As Directed; Verify That The Ignition Is In Run; Wait 30 Seconds After Changing The Seat Weight Before Proceeding To Allow The System To Stabilize; Only Press Scan Tool Buttons When Directed To Do So; and Perform The Occupant Classification Module System Verification Test To Completion. Occupant Classification Module (OCM) System Verification Test
With the scan tool in OCM, select More Options, select System Tests, and select Occupant Classification Module System Verification Test. Run the test by following the instructions displayed on the scan tool. When the test is complete, wait two minutes, and then proceed as follows.
With the scan tool, read OCM DTCs.
Q: Does the scan tool display active: B1B7A-PASSENGER SEAT WEIGHT SENSOR 3 - LEFT FRONT INPUT CIRCUIT HIGH?
YES: Go To 4
NO: Go To 9
4. INSPECT PASSENGER SEAT HARNESS WIRES AND CONNECTORS
WARNING: TO AVOID PERSONAL INJURY OR DEATH, TURN THE IGNITION OFF, DISCONNECT THE BATTERY AND WAIT TWO MINUTES BEFORE PROCEEDING.
Using the wiring diagram/schematic as a guide, inspect the Passenger Seat Harness wiring and connectors. Look for chafed, pierced, pinched, or partially broken wires and broken, bent, pushed out, spread, corroded, or contaminated terminals.
Q: Are any of these conditions present?
YES:
NOTE: Do not attempt to repair the Seat Harness. Replace the Seat Harness if any of these conditions exist.
Replace the Passenger Seat Harness. Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test
Perform the AIRBAG SYSTEM VERIFICATION TEST - VER 1. Airbag System Verification Test
NO: Go To 5
5. VERIFY THAT PASSENGER SEAT HARNESS IS ROUTED CORRECTLY
Verify that the Passenger Seat Harness is routed correctly.
Q: Is the Passenger Seat Harness routed correctly?
YES: Go To 6
NO: Reroute the Passenger Seat Harness as necessary. Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test
Perform the AIRBAG SYSTEM VERIFICATION TEST - VER 1. Airbag System Verification Test
6. CHECK (R717) LT-FT SEAT WEIGHT SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
WARNING: TO AVOID PERSONAL INJURY OR DEATH, TURN THE IGNITION OFF, DISCONNECT THE BATTERY AND WAIT TWO MINUTES BEFORE PROCEEDING.
Disconnect the OCM C2 connector.
WARNING: TO AVOID PERSONAL INJURY OR DEATH, TURN THE IGNITION ON, THEN RECONNECT THE BATTERY.
Measure the voltage of the (R717) LT-FT Seat Weight Sensor Signal circuit to ground.
Q: Is the voltage above 0.2 volts?
YES: Replace the Passenger Seat Harness. Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test
Perform the AIRBAG SYSTEM VERIFICATION TEST - VER 1. Airbag System Verification Test
NO: Go To 7
7. CHECK (R717) LT-FT SEAT WEIGHT SENSOR SIGNAL CIRCUIT FOR A SHORT TO (R701) SEAT WEIGHT SENSOR 5 VOLT CIRCUIT
WARNING: TO AVOID PERSONAL INJURY OR DEATH, TURN THE IGNITION OFF, DISCONNECT THE BATTERY AND WAIT TWO MINUTES BEFORE PROCEEDING.
Disconnect the Left-Front Seat Weight Sensor connector.
Measure the resistance between the (R717) LT-FT Seat Weight Sensor Signal circuit and the (R701) Seat Weight Sensor 5 Volt circuit.
Q: Is the resistance below 10K ohms?
YES:
NOTE: Do not attempt to repair the Seat Harness. Replace the Seat Harness if any of these conditions exist.
Replace the Passenger Seat Harness. Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test
Perform the AIRBAG SYSTEM VERIFICATION TEST - VER 1. Airbag System Verification Test
NO: Go To 8
8. CHECK (R728) SEAT WEIGHT SENSOR GROUND CIRCUIT FOR AN OPEN
Measure the resistance of the (R728) Seat Weight Sensor Ground circuit between the OCM C2 connector and the Left-Front Seat Weight Sensor connector.
Q: Is the resistance below 5.0 ohms?
YES: Replace the OCM. Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test
Perform the AIRBAG SYSTEM VERIFICATION TEST - VER 1. Airbag System Verification Test
NO:
NOTE: Do not attempt to repair the Seat Harness. Replace the Seat Harness if any of these conditions exist.
Replace the Passenger Seat Harness. Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test
Perform the AIRBAG SYSTEM VERIFICATION TEST - VER 1. Airbag System Verification Test
9. CHECKING STORED OR INTERMITTENT CODES
NOTE: Diagnose and repair all active codes before diagnosing stored codes. Refer to complete list of airbag system diagnostic procedures.
With the scan tool, record and erase all Airbag System Module DTCs.
WARNING: TO AVOID PERSONAL INJURY OR DEATH, TURN THE IGNITION OFF, DISCONNECT THE BATTERY AND WAIT TWO MINUTES BEFORE PROCEEDING.
Using the wiring diagram/schematic as a guide, inspect the related wiring and connectors for chafed, pierced, pinched, and partially broken wires, and for broken, bent, pushed out, corroded, and contaminated terminals. Repair as necessary.
Reconnect all disconnected components and harness connectors.
WARNING: TO AVOID PERSONAL INJURY OR DEATH, TURN THE IGNITION ON, THEN RECONNECT THE BATTERY.
With the scan tool, monitor for active codes while performing the following:
- Wiggle the wiring harness and connectors of the related airbag circuit.
- Continue the test until either a code becomes active or the problem area is isolated.
In the previous steps you have attempted to recreate the conditions responsible for setting the DTC in question/ causing the intermittent condition.
Q: Are any ACTIVE DTCs present?
YES: Select the appropriate diagnostic procedure.
NO: No problem found at this time. Perform the OCCUPANT CLASSIFICATION MODULE SYSTEM VERIFICATION TEST. Occupant Classification Module (OCM) System Verification Test
Erase all codes before returning vehicle to customer.