Circuit Description
The memory seat module (MSM) receives inputs from the seat position sensors during the following functions:
| • | Memory recall |
| • | Memory set |
| • | Easy exit |
The potentiometers in the position sensors vary in resistance as the motors move the seat. The MSM receives a variable voltage input depending on the resistance of the potentiometer. During memory set, the MSM records the voltage across all seat potentiometers. During memory recall, the MSM moves the seat motors until the voltage across each potentiometer matches the stored voltages. For the easy exit function, the MSM moves the seat motors until the voltages match what the MSM recorded in memory for the easy exit. During normal operation the seat position sensors are checked against out-of-range limits.
Conditions for Setting the DTC
| • | The DTC sets only if the following DTCs are not current: |
| - | DTC MSM B1982 |
| - | DTC MSM B1983 |
| • | The MSM will set the appropriate DTC any time the MSM detects the sensor input voltage is out of the range: 0.25-4.75 V. |
Action Taken When the DTC Sets
When a position sensor DTC is set as current the MSM disables the affected motor during the following operations:
| • | Memory recall |
| • | Easy exit |
The motor remains enabled for manual positioning.
Conditions for Clearing the DTC
The DTC clears when the MSM does not detect a position sensor failure during the last monitoring cycle.
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Power Seat Systems Diagnostic System Check? | -- | Go to Step 2 | |
Is the voltage within the specified range? | 4.6-5.2 V | Go to Step 3 | Go to Step 5 | |
3 | Test CKT 569 (DK GRN) for an open or a short. Refer to Testing for Continuity in Wiring Systems. Is there an open or a short in CKT 569? | -- | Go to Step 8 | Go to Step 4 |
4 | Replace the appropriate position sensor. Is the position sensor replacement complete? | -- | Go to Step 10 | -- |
5 | Test CKT 788 (GRY) between the position sensor and S334 for an open. Refer to Testing for Continuity in Wiring Systems. Is there an open in CKT 788? | -- | Go to Step 8 | Go to Step 6 |
6 | Test CKT 782 (BLK) between the position sensor and S336 for an open. Refer to Testing for Continuity in Wiring Systems. Is there an open in CKT 782? | -- | Go to Step 8 | Go to Step 7 |
7 |
Is there proper terminal contact? | -- | Go to Step 9 | Go to Step 10 |
8 | Repair the faulty wiring. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 11 | -- |
9 | Replace the MSM. Refer to Memory Seat Control Module Replacement Is the MSM replacement complete? | -- | Go to Step 11 | -- |
10 | Clean or repair the terminal contacts as needed. Refer to Repairing Connector Terminals in Wiring Systems. Is the repair complete? | -- | Go to Step 11 | -- |
11 |
Did you clear the DTCs and perform the Power Seat Systems Diagnostic System Check? | -- | -- |
