B1B84-PASSENGER SEAT WEIGHT SENSOR 4 - LEFT REAR INPUT CIRCUIT HIGH

For a complete wiring diagram Refer to Section 8W.

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

(R705) LT-RR SEAT WEIGHT SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE

(R705) LT-RR SEAT WEIGHT SENSOR SIGNAL CIRCUIT SHORTED TO (R701) SEAT WEIGHT SENSOR 5 VOLT CIRCUIT

(R728) SEAT WEIGHT SENSOR GROUND CIRCUIT OPEN

LEFT-REAR 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.

Turn the ignition on, then off, and then on again.
With the scan tool, read Occupant Classification Module (OCM) DTC.

Does the scan tool display any active DTC relating to internal faults, ignition faults, or battery faults?

Yes

Diagnose and repair the DTC. Refer to the Table of Contents in this Section for a complete list of symptoms.

Go To 2

2. VERIFY THAT DTC B1B84-PASSENGER SEAT WEIGHT SENSOR 4 - LEFT REAR INPUT CIRCUIT HIGH IS ACTIVE

NOTE: Failure to follow the 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.

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 DTC.

Does the scan tool display active: B1B84-PASSENGER SEAT WEIGHT SENSOR 4 - LEFT REAR INPUT CIRCUIT HIGH?

Yes

Go To 3

Go To 9

3. VERIFY THAT DTC B1B84-PASSENGER SEAT WEIGHT SENSOR 4 - LEFT REAR INPUT CIRCUIT HIGH IS ACTIVE

Verify that all of the Seat Weight Sensor mounting screws are tightened to torque specification. Refer to GROUP 23 for specification.

Go To 4

Go To 9

4. INSPECT PASSENGER SEAT HARNESS WIRES AND CONNECTORS

WARNING: To avoid serious or fatal injury, 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.

Are any of these conditions present?

Yes

NOTE: Do not attempt to repair the Seat Harness. Replace the Seat Harness if the condition inspecting or testing for is present in the Seat Harness.
Replace the Passenger Seat Harness in accordance with the Service Information.
Perform *OCM SYSTEM VERIFICATION TEST.

Go To 5

5. VERIFY THAT PASSENGER SEAT HARNESS IS ROUTED CORRECTLY

Verify that the Passenger Seat Harness is routed correctly.

Is the Passenger Seat Harness routed correctly?

Yes

Go To 6

Reroute the Passenger Seat Harness as necessary.
Perform *OCM SYSTEM VERIFICATION TEST.

6. CHECK (R705) LT-RR SEAT WEIGHT SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE

Disconnect the OCM C2 connector.
Measure the voltage of the (R705) LT-RR Seat Weight Sensor Signal circuit.

Is the voltage above 0.2 volt?

Yes

NOTE: Do not attempt to repair the Seat Harness. Replace the Seat Harness if the condition inspecting or testing for is present in the Seat Harness.
Replace the Passenger Seat Harness in accordance with the Service Information.
Perform *OCM SYSTEM VERIFICATION TEST.

Go To 7

7. CHECK (R705) LT-RR SEAT WEIGHT SENSOR SIGNAL CIRCUIT FOR A SHORT TO (R701) SEAT WEIGHT SENSOR 5 VOLT CIRCUIT

Disconnect the Left-Rear Seat Weight Sensor connector.
Measure the resistance between the (R705) LT-RR Seat Weight Sensor Signal circuit and the (R701) Seat Weight Sensor 5 Volt circuit.

Is the resistance below 5.0 ohms?

Yes

NOTE: Do not attempt to repair the Seat Harness. Replace the Seat Harness if the condition inspecting or testing for is present in the Seat Harness.
Replace the Passenger Seat Harness in accordance with the Service Information.
Perform *OCM SYSTEM VERIFICATION TEST.

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-Rear Seat Weight Sensor connector.

Is the resistance below 5.0 ohms?

Yes

Replace the OCM in accordance with the Service Information.
Perform *OCM SYSTEM VERIFICATION TEST.

NOTE: Do not attempt to repair the Seat Harness. Replace the Seat Harness if the condition inspecting or testing for is present in the Seat Harness.
Replace the Passenger Seat Harness in accordance with the Service Information.
Perform *OCM SYSTEM VERIFICATION TEST.

9. CHECKING STORED OR INTERMITTENT CODES

NOTE: Diagnose and repair all active codes before diagnosing stored codes. Refer to the Table of Contents in this Section for a complete list of airbag system diagnostic procedures.

With the scan tool, record and erase all Airbag System Module DTC.

WARNING: To avoid serious or fatal injury, 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 serious or fatal injury, 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.

Are any ACTIVE DTC present?

Yes

Select the appropriate diagnostic procedure from the Table of Contents in this section.

No problem found at this time. Perform the Occupant Classification Module System Verification Test in this Section. Erase all codes before returning vehicle to customer.