B1D5E
B1D5E-13-POWER SEAT SWITCH-CIRCUIT OPEN
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Memory System is made up of the Memory Seat Module-Driver (MSMD), Memory Switch, Driver Seat Switch, Adjustable Pedal Switch, and multiple Seat Motors and an Adjustable Pedal Motor. The motors each contain a hall-effect position sensor. The hall-effect position sensor provides feedback to the MSMD in relation to the motors position.
The Driver Seat Switch is a Multiplex (Mux) switch which uses set resistance levels for each switch position. These resistances correspond to different voltages which is monitored by the MSMD over two separate circuits. When a voltage change is detected, the MSMD will command the appropriate Seat motor(s) to move the seat in the requested direction as long as the Driver Seat Switch is held in that direction or its stops have been reached.
The Adjustable Pedal Switch is a three position switch (forward, center, rearward). The MSMD monitors the forward and rearward circuits voltage. If a voltage change is detected, the MSMD will command the Adjustable Pedal motor to move the pedals in the requested direction as long as the Adjustable Pedal Switch is held in that direction or its stops have been reached.
The Memory Switch is a Mux switch that is used to set and recall the seat and pedal positions. When a Memory Switch button is pressed, the Driver Door Module (DDM) detects a voltage change and sends a request over the Controller Area Network (CAN) bus circuit to the MSMD to perform the requested command. If the SET button on the Memory Switch is pressed, followed by the 1 or 2 button, the MSMD will store the seat and pedal positions based on the position inputs received from the hall-effect position sensors. If the 1 or 2 button on the Memory Switch is pressed, the MSMD will recall the stored seat and pedal positions for that particular selection and return the seat and pedals to the stored positions. Memory position may also be recalled using a linked FOBIK transmitter. For driver safety, the MSMD will prevent the memory recall function from being initiated if the transmission gear selector lever is not in the Park position or if the vehicle is moving. For further information Memory Seat Module - Operation.
- When Monitored:
Continuously.
- Set Condition:
The MSMD detects an open in either Driver Seat Switch MUX circuit.
Diagnostic Test
1. CHECK IF THE DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, record and erase Memory Seat Module-Driver (MSMD) DTCs.
3. Cycle the ignition switch from off to on.
4. Cycle the Power Seat Switch to all positions.
5. With the scan tool, read MSMD DTCs.
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
- Perform the POWER SEAT SYSTEM VERIFICATION TEST. Verification Tests.
2. CHECKING THE DRIVER SEAT SWITCH MUX RETURN CIRCUIT
1. Turn the ignition off.
2. Disconnect the Driver Seat Switch harness connector.
3. Using the Driver Seat Switch Continuity chart, measure the resistance of the Driver Seat Switch in the Off position.
Is the resistance within specifications?
Yes
- Go To 3
No
- Replace the Driver Seat Switch. Power Seat Switch - Removal.
- Perform the POWER SEAT SYSTEM VERIFICATION TEST. Verification Tests.
3. CHECK THE (P599) DRIVER SEAT SWITCH MUX RETURN CIRCUIT FOR AN OPEN
1. Disconnect the MSMD C7 harness connector.
2. Measure the resistance of the (P599) Driver Seat Switch Mux Return circuit between the MSMD C7 harness connector and the Driver Seat Switch harness connector.
Is the resistance below 1.0 Ohm?
Yes
- Go To 4
No
- Repair the (P599) Driver Seat Switch Mux Return circuit for an open or high resistance.
- Perform the POWER SEAT SYSTEM VERIFICATION TEST. Verification Tests.
4. CHECK THE (P339) DRIVER SEAT SWITCH FRONT VERTICAL/RECLINER SWITCH MUX CIRCUIT FOR AN OPEN
1. Measure the resistance of the (P339) Driver Seat Switch Front Vertical/Recliner Switch Mux circuit between the MSMD C7 harness connector and the Driver Seat Switch harness connector.
Is the resistance below 1.0 Ohm?
Yes
- Go To 5
No
- Repair the (P339) Driver Seat Switch Front Vertical/Recliner Switch Mux circuit for an open or high resistance.
- Perform the POWER SEAT SYSTEM VERIFICATION TEST. Verification Tests.
5. CHECK THE (P239) DRIVER SEAT SWITCH REAR VERTICAL/HORIZONTAL SWITCH MUX CIRCUIT FOR AN OPEN
1. Measure the resistance of the (P239) Driver Seat Switch Rear Vertical/Horizontal Switch Mux circuit between the MSMD C7 harness connector and the Driver Seat Switch harness connector.
Is the resistance below 1.0 Ohm?
Yes
- Replace the Driver Seat Switch. Power Seat Switch - Removal.
- Perform the POWER SEAT SYSTEM VERIFICATION TEST. Verification Tests.
No
- Repair the (P239) Driver Seat Switch Rear Vertical/Horizontal Switch Mux circuit for an open or high resistance.
- Perform the POWER SEAT SYSTEM VERIFICATION TEST. Verification Tests.
6. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit. Wiggle the wiring and connectors while checking for shorted and open circuits. Attempt to reproduce the condition by adjusting the seat(s).
3. Check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
4. Check Service Bulletins for any possible causes that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWER SEAT SYSTEM VERIFICATION TEST. Verification Tests.
No
- Test complete.