Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Lumbar Massage Switch Supply Voltage | 2 | 1 | -- | -- |
5-Volt Reference | B1395 02 | B1395 05 | B1395 05 | -- |
Lumbar Massage Switch Signal | 2 | 1 | 1 | -- |
Lumbar Vertical Position Sensor Signal | B2105 or B2355 | B2105 or B2355 | B2105 or B2355 | -- |
Lumbar Motor Down Control | B1340 0B | B1340 00 | B2765 | -- |
Lumbar Motor Up Control | B1340 0B | B1340 00 | -- | -- |
Memory Seat/Mirror Sensor Low Reference | -- | B1395 05 | -- | -- |
1. Lumbar massage inoperative 2. Loss of Communication with MSM | ||||
Circuit/System Description
Battery positive voltage is supplied to the driver seat lumbar massage switch from the memory seat module (MSM) and to the passenger front seat from the MSM fuse. When the lumbar massage switch is pressed, battery voltage is applied through the switch contacts and the lumbar massage signal circuit to the MSM. The MSM then cycles battery voltage and ground through the lumbar vertical motor control circuits to the lumbar vertical motor for 10 minutes or until the massage function is canceled. The MSM supplies the lumbar vertical position sensor with a 5-volt reference and low reference circuits. When the motor rotates, the resistance of the potentiometer varies changing the voltage of the lumbar vertical position sensor signal to the MSM.
Diagnostic Aids
The MSM is referenced in the Tech 2 as the driver position module (DPM).
Reference Information
Schematic Reference
Connector End View Reference
Power Seat Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, use a scan tool to observe the Massage Switch parameter while pressing the massage switch. The reading should change between Inactive and Active.
Circuit/System Testing
- Using a scan tool verify the Massage Switch parameter is Inactive.
- Ignition OFF, disconnect the harness connector at the lumbar massage switch.
- Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal C and ground.
- Install a 3-amp fused jumper wire between the voltage supply circuit terminal C and the signal circuit terminal A. Verify the Massage Switch parameter is Active.
- If all circuits tests normal, replace the lumbar massage switch.
| ⇒ | If not Inactive, test the signal circuit for a short to voltage. If the circuit tests normal, replace the memory seat module. |
| ⇒ | If the test lamp does not illuminate, test the supply voltage for an open/high resistance. |
| ⇒ | If not Active, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the memory seat module. |
Component Testing
Lumbar Massage Switch
- Ignition OFF, disconnect the harness connector at the lumbar massage switch.
- Test for infinite resistance between the signal terminal and the supply voltage terminal with the switch in the open position.
- Test for less than 3 ohms between the signal terminal and the supply voltage terminal with the switch in the closed position.
| ⇒ | If less than infinite, replace the lumbar massage switch. |
| ⇒ | If greater than 3 ohms, replace the lumbar massage switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for MSM replacement, programming and setup |
