Pinpoint Test BZ: Power-Fold Seat Motor (Backrest) and Sensor Functional Test - RH Third Row Power Seat
Seats
Pinpoint Test BZ: Power-Fold Seat Motor (Backrest) and Sensor Functional Test - RH Third Row Power Seat
Normal Operation
The Power-Fold Seat Module (PFSM) supplies voltage and ground to the power-fold seat motor to move the seat to and from the FOLD and NORMAL positions when selected by the seat control switch. When FOLD is selected the backrest will fold forward and release the spring loaded headrest. If an obstruction is detected in the FOLD/NORMAL axis of movement the seat will stop, reverse movement a few inches and then stop again until the obstruction is removed. When the obstruction has been removed the seat control switch must be depressed again to reset the request. The seat will go to the power-fold seat motor home position (seat folded and latched to floor) and then continue with any seat position requested. If the PFSM (Power-Fold Seat Module) detects a power-fold seat motor circuit fault (open or short), motor operation will be disabled. If a short to ground is present the motor will work in only one direction.
A Hall effect sensor is located inside each of the power-fold seat motor assemblies to detect motor movement and seat position to the PFSM (Power-Fold Seat Module). If the sensor does not detect motor movement during a request from the seat control switch, the PFSM (Power-Fold Seat Module) will disable power-fold seat motor output.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Power-fold seat motor (backrest) and sensor
- PFSM (Power-Fold Seat Module)
PINPOINT TEST BZ : POWER-FOLD SEAT MOTOR (BACKREST) AND SENSOR FUNCTIONAL TEST - RH THIRD ROW POWER SEAT
NOTICE: The following pinpoint test uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
NOTE: Verify good battery condition before diagnosing the Power-Fold Seat Module (PFSM) system. Poor battery condition may interfere with PFSM (Power-Fold Seat Module) operation. If battery voltage drops below 10 volts, seat movement will not start. If battery voltage drops below 8 volts, a started seat movement will stop.
NOTE: The accessory delay system (courtesy lamps) will time-out after 10 minutes and disable the third row power seat operation. Meter voltage measurements will be inaccurate when this occurs, which could lead to misdiagnosis. To enable the accessory delay system during diagnosis and testing, close and open any vehicle door.
BZ1 CONFIRM THE FUNCTIONAL TEST HAS BEEN COMPLETED
- Verify the Function- Third Row Power Seat Test has been completed before testing the power-fold seat motor (backrest) and sensor.
Has the System Function Test been completed?
Yes
GO to BZ2.
No
CARRY OUT the Functional Test - Third Row Power Seat. GO to Pinpoint Test BT and return to this test only if directed to do so. Pinpoint Test BT: Functional Test - Third Row Power Seat
BZ2 CHECK THE PFSM (Power-Fold Seat Module) FOR OUTPUT VOLTAGE TO THE POWER-FOLD SEAT MOTOR
- Access the PFSM (Power-Fold Seat Module). To access the PFSM (Power-Fold Seat Module), refer to the appropriate steps in Power-Fold Seat Module (PFSM) .
- Verify the vehicle is in PARK and the liftgate is open.
- Verify the courtesy lights are on. If needed, close and open any door on the vehicle.
- Connect a test lamp between PFSM (Power-Fold Seat Module) C4250B-4, circuit CPS44 (GY/BN) and PFSM (Power-Fold Seat Module) C4250B-2, circuit CPS45 (VT/OG), by back-probing the connector.
- Press the NORMAL button, then the FOLD button, monitor the test lamp and allow the seat to complete any movement.
- If the seat is already in the normal position, press the fold button instead.
Does the test lamp illuminate (may be momentary) when either button is pressed?
Yes
GO to BZ5.
No
GO to BZ3.
BZ3 CHECK THE POWER-FOLD SEAT MOTOR AND CIRCUITS FOR A SHORT TO GROUND
- Disconnect: PFSM (Power-Fold Seat Module) C4250B.
- Measure the resistance between:
- PFSM (Power-Fold Seat Module) C4250B-4, circuit CPS44 (GY/BN), harness side and ground.
- PFSM (Power-Fold Seat Module) C4250B-2, circuit CPS45 (VT/OG), harness side and ground.
Are the resistances greater than 10,000 ohms?
Yes
GO to BZ11.
No
GO to BZ4.
BZ4 CHECK THE POWER-STOW SEAT MOTOR AND CIRCUITS FOR A SHORT TO GROUND
- Remove the backrest latch outer cover to gain access to the RH power-fold seat motor electrical connector. Refer to Seat- Exploded View, Third Row .
- Disconnect: RH Power-Fold Seat Motor C4246.
- Measure the resistance between:
- PFSM (Power-Fold Seat Module) C4250B-4, circuit CPS44 (GY/BN), harness side and ground.
- PFSM (Power-Fold Seat Module) C4250B-2, circuit CPS45 (VT/OG), harness side and ground.
Are the resistances greater than 10,000 ohms?
Yes
INSTALL a new power-fold seat motor. REFER to Power-Fold Seat Motor - Third Row . TEST the system for normal operation.
No
REPAIR the circuit(s). TEST the system for normal operation.
BZ5 CHECK THE POWER-FOLD SEAT MOTOR AND CIRCUITS FOR AN OPEN
- Disconnect: PFSM (Power-Fold Seat Module) C4250B.
- Measure the resistance between PFSM (Power-Fold Seat Module) C4250B-4, circuit CPS44 (GY/BN), harness side and PFSM (Power-Fold Seat Module) C4250B-2, circuit CPS45 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to BZ7.
No
GO to BZ6.
BZ6 CHECK THE POWER-FOLD SEAT MOTOR CIRCUITS FOR AN OPEN
- Remove the backrest latch outer cover to gain access to the RH power-fold seat motor electrical connector. Refer to Seat- Exploded View, Third Row .
- Disconnect: RH Power-Fold Seat Motor C4246.
- Measure the resistance between:
- PFSM (Power-Fold Seat Module) C4250B-4, circuit CPS44 (GY/BN), harness side and RH power-fold seat motor C4246-3, circuit CPS44 (GY/BN), harness side.
- PFSM (Power-Fold Seat Module) C4250B-2, circuit CPS45 (VT/OG), harness side and RH power-fold seat motor C4246-1, circuit CPS45 (VT/OG), harness side.
Are the resistances less than 5 ohms?
Yes
INSTALL a new power-fold seat motor. REFER to Power-Fold Seat Motor - Third Row . TEST the system for normal operation.
No
REPAIR the circuit(s). TEST the system for normal operation.
BZ7 CHECK THE PFSM (Power-Fold Seat Module) FOR OUTPUT VOLTAGE TO THE FOLD SENSOR
- Connect: PFSM (Power-Fold Seat Module) C4250B.
- Verify the vehicle is in PARK and the liftgate is open.
- Verify the courtesy lights are on. If needed, close and open any door on the vehicle.
- Measure the voltage between PFSM (Power-Fold Seat Module) C4250B-5, circuit LPS78 (VT) and PFSM (Power-Fold Seat Module) C4250B-1, circuit RPS77 (BN/GN), by back-probing the connector.
Is the voltage greater than 5 volts?
Yes
GO to BZ10.
No
GO to BZ8.
BZ8 CHECK THE FOLD SENSOR AND CIRCUITS FOR A SHORT TO GROUND
- Disconnect: PFSM (Power-Fold Seat Module) C4250B.
- Measure the resistance between PFSM (Power-Fold Seat Module) C4250B-5, circuit LPS78 (VT), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to BZ11.
No
GO to BZ9.
BZ9 CHECK THE FOLD SENSOR CIRCUIT FOR A SHORT TO GROUND
- Remove the backrest latch outer cover to gain access to the power-fold seat motor electrical connector. Refer to Seat- Exploded View, Third Row .
- Disconnect: RH Power-Fold Seat Motor C4246.
- Measure the resistance between PFSM (Power-Fold Seat Module) C4250B-5, circuit LPS78 (VT), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new power-fold seat motor assembly. REFER to Power-Fold Seat Motor - Third Row . TEST the system for normal operation.
No
REPAIR the circuit. TEST the system for normal operation.
BZ10 CHECK THE FOLD SENSOR CIRCUITS FOR AN OPEN
- Remove the backrest latch outer cover to gain access to the power-fold seat motor electrical connector. Refer to Seat- Exploded View, Third Row .
- Disconnect: RH Power-Fold Seat Motor C4246.
- Disconnect: PFSM (Power-Fold Seat Module) C4250B.
- Measure the resistance between:
- PFSM (Power-Fold Seat Module) C4250B-5, circuit LPS78 (VT), harness side and RH power-fold seat motor C4246-2, circuit LPS78 (VT), harness side.
- PFSM (Power-Fold Seat Module) C4250B-1, circuit RPS77 (BN/GN), harness side and RH power-fold seat motor C4246-4, circuit RPS77 (BN/GN), harness side.
Are the resistances less than 5 ohms?
Yes
INSTALL a new power-fold seat motor assembly. REFER to Power-Fold Seat Motor - Third Row . TEST the system for normal operation.
No
REPAIR the circuit(s). TEST the system for normal operation.
BZ11 CHECK PFSM (Power-Fold Seat Module) CONNECTORS AND PINS FOR DAMAGE AND RETEST THE SYSTEM
- Inspect the PFSM (Power-Fold Seat Module) connectors for corrosion and pushed out or damaged pins and repair as necessary.
- Reconnect all the PFSM (Power-Fold Seat Module) connectors.
- Operate the seats and determine if the concern is still present.
Is the concern still present?
Yes
INSTALL a new PFSM (Power-Fold Seat Module). Refer to Power-Fold Seat Module (PFSM) . TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.