00-Seat Backrest Motor Control Circuit Performance
B1D87-00-Seat Backrest Motor Control Circuit Performance
For a complete wiring diagram, refer to.
Theory of Operation
The Memory System is made up of the Memory Seat Module (MSMD), Memory Switch, Driver Seat Switch, Tilt/Telescope Switch, multiple Seat Motors which also each contain a hall-effect position sensor, and the Tilt and Telescope Steering Motors, both of which contain a hall-effect position sensor.
When the Driver Seat Switch is used to command seat movement, a signal is sent from the Switch to the MSMD via a mux signal circuit. The MSMD will then command the appropriate Seat Motor or Motors to move the seat in the commanded direction as long as the Driver Seat Switch is held in that direction. When seat movement is commanded, the MSMD also powers the hall-effect position sensor located in each Seat Motor. These hall-effect sensors provide feedback to the MSMD in relation to the seat's position. The Tilt and Telescoping Steering operate in a similar manner, with the Tilt Switch and Telescope Switch sending a signal to the MSMD from the Steering Column Control Module (SCCM) via the Controller Area Network (CAN) bus circuit. The Tilt Motor and Telescope Motor are then commanded by the MSMD based on the Switch input. The Tilt Motor and Telescope Motor also each have a hall-effect position sensor.
The Memory Switch is used to set and recall memory seat and steering positions. When a Memory Switch button is pressed, a signal is sent from the Switch to the Driver Door Module (DDM) via a mux signal circuit. The DDM will then request the MSMD perform the function via the Controller Area Network (CAN) bus circuit. If the SET button on the Memory Switch is pressed, followed by the 1 or 2 button, the MSMD will store the seat and steering position based on the position inputs received from the hall-effect position sensor. If the 1 or 2 button on the Memory Switch is pressed, the MSMD will recall the stored position for that particular selection and return the seat and steering column to the stored position. 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.
• When Monitored: The seat motor is activated.
• Set Condition: The MSMD does not detect seat motor activation. The DTC will only set when the seat switch is moved in the same direction three consecutive times.
Test Step 1 - CHECK FOR RELATED DIAGNOSTIC TROUBLE CODES
• Turn the ignition on.
• With the scan tool, read DTCs.
Does the scan tool display any seat position sensor DTCs?
Yes
• Diagnose and repair the other DTC(s) first.
No
• Go to Test Step 2 => [ Test Step 2 - TEST FOR INTERMITTENT CONDITION ]
Test Step 2 - TEST FOR INTERMITTENT CONDITION
• Turn the ignition on.
• With the scan tool, record and erase DTCs
• Move the Seat Switch in the recline position three times.
• With the scan tool, read the active DTCs.
Does the scan tool display B1D87-00-SEAT BACKREST MOTOR CONTROL CIRCUIT PERFORMANCE?
Yes
• Go to Test Step 3 => [ Test Step 3 - CHECKING THE (G403) DRIVER SEAT RECLINER POSITION SENSE
CIRCUIT ]
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 Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
Test Step 3 - CHECKING THE (G403) DRIVER SEAT RECLINER POSITION SENSE CIRCUIT
• Disconnect the Driver Recliner Seat Adjuster Motor harness connector.
• Measure the voltage between the (G403) Driver Seat Recliner Position Sense circuit and ground.
Is the voltage above 11 volts?
Yes
• Go to Test Step 4 => [ Test Step 4 - CHECKING THE (G493) DRIVER SEAT RECLINER POSITION SENSOR
GROUND CIRCUIT ]
No
• Go to Test Step 11 => [ Test Step 11 - CHECKING THE (G403) DRIVER SEAT RECLINER POSITION
SENSE CIRCUIT FOR AN OPEN OR EXCESSIVE RESISTANCE ]
Test Step 4 - CHECKING THE (G493) DRIVER SEAT RECLINER POSITION SENSOR GROUND CIRCUIT
• Measure the voltage between the (G403) Driver Seat Recliner Position Sense circuit and the (G493) Driver Seat Recliner Position Sensor Ground circuit.
Is the voltage above 11 volts?
Yes
• Go to Test Step 5 => [ Test Step 5 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER
CIRCUIT ]
No
• Go to Test Step 12 => [ Test Step 12 - CHECKING THE (G493) DRIVER SEAT RECLINER POSITION
SENSOR GROUND CIRCUIT FOR AN OPEN OR EXCESSIVE RESISTANCE ]
Test Step 5 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER CIRCUIT
• Measure the voltage between the (P141) Driver Seat Recliner Up Driver circuit and ground.
Is the voltage above 1 volt?
Yes
• Go to Test Step 13 => [ Test Step 13 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER
CIRCUIT FOR A SHORT TO VOLTAGE ]
No
• Go to Test Step 6 => [ Test Step 6 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER
CIRCUIT ]
Test Step 6 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER CIRCUIT
• Measure the voltage between the (P143) Driver Seat Recliner Down Driver circuit and ground.
Is the voltage above 1 volt?
Yes
• Go to Test Step 14 => [ Test Step 14 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER
CIRCUIT FOR A SHORT TO VOLTAGE ]
No
• Go to Test Step 7 => [ Test Step 7 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER
CIRCUIT ]
Test Step 7 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER CIRCUIT
• Connect a 12-volt test light between the (P141) Driver Seat Recliner Up Driver circuit and ground.
• While observing the test light, move the Driver Seat Recliner Switch in the up position.
• The test lamp must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test lamp illuminate brightly?
Yes
• Go to Test Step 8 => [ Test Step 8 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER
CIRCUIT ]
No
• Go to Test Step 15 => [ Test Step 15 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER
CIRCUIT FOR A SHORT TO GROUND ]
Test Step 8 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER CIRCUIT
• Connect a 12-volt test light between the (P143) Driver Seat Recliner Down Driver circuit and ground.
• While observing the test light, move the Driver Seat Recliner Switch in the down position.
• The test lamp must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test lamp illuminate brightly?
Yes
• Go to Test Step 9 => [ Test Step 9 - CHECKING THE DRIVER SEAT RECLINER DOWN DRIVER ]
No
• Go to Test Step 17 => [ Test Step 17 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER
CIRCUIT FOR A SHORT TO GROUND ]
Test Step 9 - CHECKING THE DRIVER SEAT RECLINER DOWN DRIVER
• Connect a 12-volt test light between the (P141) Driver Seat Recliner Up Driver circuit and the (P143) Driver Seat Recliner Down Driver circuit.
• While observing the test light, move the Driver Seat Recliner Switch in the up position.
• The test lamp must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test lamp illuminate brightly?
Yes
• Go to Test Step 10 => [ Test Step 10 - CHECKING THE DRIVER SEAT RECLINER UP DRIVER ]
No
• Go to Test Step 19 => [ Test Step 19 - MEMORY SEAT MODULE (MSMD) ]
Test Step 10 - CHECKING THE DRIVER SEAT RECLINER UP DRIVER
• While observing the test light, move the Driver Seat Recliner Switch in the down position.
• The test lamp must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test lamp illuminate brightly?
Yes
• Replace the Seat Adjuster Recliner Motor Assembly.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Go to Test Step 19 => [ Test Step 19 - MEMORY SEAT MODULE (MSMD) ]
Test Step 11 - CHECKING THE (G403) DRIVER SEAT RECLINER POSITION SENSE CIRCUIT FOR AN OPEN OR EXCESSIVE RESISTANCE
• Turn the ignition off.
• Disconnect the MSMD C2 harness connector.
• Measure the resistance of the (G403) Driver Seat Recliner Position Sense circuit between the Driver Seat Recliner Adjuster Motor harness connector and the MSMD harness connector.
Is the resistance above 10 Ohms?
Yes
• Repair the open or excessive resistance in the (G403) Driver Seat Recliner Position Sense circuit.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Go to Test Step 19 => [ Test Step 19 - MEMORY SEAT MODULE (MSMD) ]
Test Step 12 - CHECKING THE (G493) DRIVER SEAT RECLINER POSITION SENSOR GROUND CIRCUIT FOR AN OPEN OR EXCESSIVE RESISTANCE
• Turn the ignition off.
• Disconnect the MSMD C2 harness connector.
• Measure the resistance of the (G493) Driver Seat Recliner Position Sensor Ground circuit between the Driver Seat Recliner Adjuster Motor harness connector and the MSMD harness connector.
Is the resistance above 10 Ohms?
Yes
• Repair the open or excessive resistance in the (G493) Driver Seat Recliner Position Sensor Ground circuit.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Go to Test Step 19 => [ Test Step 19 - MEMORY SEAT MODULE (MSMD) ]
Test Step 13 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER CIRCUIT FOR A SHORT TO VOLTAGE
• Disconnect the MSMD C2 harness connector.
• Measure the voltage between the (P141) Driver Seat Recliner Up Driver circuit and ground.
Is the voltage above 1 volt?
Yes
• Repair the short to voltage in the (P141) Driver Seat Recliner Up Driver circuit.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Go to Test Step 19 => [ Test Step 19 - MEMORY SEAT MODULE (MSMD) ]
Test Step 14 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER CIRCUIT FOR A SHORT TO VOLTAGE
• Disconnect the MSMD C2 harness connector.
• Measure the voltage between the (P143) Driver Seat Recliner Down Driver circuit and ground.
Is the voltage above 1 volt?
Yes
• Repair the short to voltage in the (P143) Driver Seat Recliner Down Driver circuit.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Go to Test Step 19 => [ Test Step 19 - MEMORY SEAT MODULE (MSMD) ]
Test Step 15 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER CIRCUIT FOR A SHORT TO GROUND
• Turn the ignition off.
• Disconnect the MSMD C2 harness connector.
• Measure the resistance between ground and the (P141) Driver Seat Recliner Up Driver circuit.
Is the resistance below 1K Ohms.
Yes
• Repair the short to ground in the (P141) Driver Seat Recliner Up Driver circuit.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Go to Test Step 16 => [ Test Step 16 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER
CIRCUIT FOR AN OPEN OR EXCESSIVE RESISTANCE ]
Test Step 16 - CHECKING THE (P141) DRIVER SEAT RECLINER UP DRIVER CIRCUIT FOR AN OPEN OR EXCESSIVE RESISTANCE
• Measure the resistance of the (P141) Driver Seat Recliner Up Driver circuit between the Driver Seat Recliner Adjuster Motor harness connector and the MSMD harness connector.
Is the resistance above 10 Ohms?
Yes
• Repair the open or excessive resistance in the (P141) Driver Seat Recliner Up Driver circuit.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Go to Test Step 19 => [ Test Step 19 - MEMORY SEAT MODULE (MSMD) ]
Test Step 17 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER CIRCUIT FOR A SHORT TO GROUND
• Turn the ignition off.
• Disconnect the MSMD C2 harness connector.
• Measure the resistance between ground and the (P143) Driver Seat Recliner Down Driver circuit.
Is the resistance below 1K Ohms?
Yes
• Repair the short to ground in the (P143) Driver Seat Recliner Down Driver circuit.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Go to Test Step 18 => [ Test Step 18 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER
CIRCUIT FOR AN OPEN OR EXCESSIVE RESISTANCE ]
Test Step 18 - CHECKING THE (P143) DRIVER SEAT RECLINER DOWN DRIVER CIRCUIT FOR AN OPEN OR EXCESSIVE RESISTANCE
• Measure the resistance of the (P143) Driver Seat Recliner Down Driver circuit between the Driver Seat Recliner Adjuster Motor harness connector and the MSMD harness connector.
Is the resistance above 10 Ohms?
Yes
• Repair the open or excessive resistance in the (P143) Driver Seat Recliner Down Driver circuit.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Go to Test Step 19 => [ Test Step 19 - MEMORY SEAT MODULE (MSMD) ]
Test Step 19 - MEMORY SEAT MODULE (MSMD)
• Using the wiring diagram/schematic as a guide, inspect the wiring and harness connectors between the Driver Seat Recliner Adjuster Motor and the MSMD.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Driver Seat Recliner Adjuster Motor and MSMD harness connectors.
• Perform any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
• Repair as necessary.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test
No
• Replace the MSMD.
• Perform Power Seat System Verification Test. Refer to => Non - DTC Based Diagnostics. Power Seat System Verification Test