Circuit Description
The memory seat module (MSM) diagnostic check is an organized approach to identify problems associated with the module. This check must be the starting point for any MSM complaint, and will direct you to the next logical step in diagnosing the complaint. The MSM is a very reliable component and is not likely the cause of the malfunction. Most system complaints are linked to faulty wiring and connectors, and occasionally to components. Understanding the computer system and using the tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.
Diagnostic Aids
| • | The following conditions may result in an intermittent operation of the module with no DTC stored: |
| - | Any condition which results in the interruption of power to the MSM |
| - | Out of range battery or ignition voltage |
Specification
Normal MSM operating voltage: 9.0-16.0 V
| - | A loose or damaged ground(s) |
| - | An open or shorted serial data line |
| • | An intermittent failure in the electronic system may be very difficult to detect and to accurately diagnose. The MSM tests for different malfunctions under different vehicle conditions. For this reason, a thorough test drive is often needed in order to repeat a malfunction. If the system malfunction is not repeated during the test drive, a good description of the complaint may be very useful in locating an intermittent malfunction. Faulty electrical connections or wiring causes most intermitting problems. When an intermitting condition is suspected, check the suspected circuits for the following conditions: |
| - | Poor mating of connector halves or backed out terminals |
| - | Improperly formed or damaged terminals |
| - | Wire chafing |
| - | Poor wire to terminal connections |
| - | Dirty or corroded terminals |
| - | Damage to connector bodies |
| • | Use the J 35616 whenever a diagnostic procedure requests probing or checking a terminal. Using this adapter will ensure that no damage to the terminal will occur, and will give an idea of whether contact tension is sufficient. |
| • | If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Perform a thorough inspection of all related wiring and connectors pertaining to the history DTC stored. |
| • | Exit all scan tool tests before cycling the ignition OFF to ON unless the scan tool instructions direct otherwise. Follow the operating instructions in the scan tool operator's manual. Failure to follow these instruction may set DTCs, cause vehicle system malfunctions, set false DTCs, or cause scan tool malfunctions. |
Test Description
The numbers below refer to the step numbers on the diagnostic table:
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This test determines if communication can be established with the memory seat module (MSM).
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This test checks for stored MSM DTCs.
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This test determines whether communication can be established with other modules connected to the Class 2 serial data line.
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This test checks for any open MSM power fuses.
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This test checks the MSM power circuit. If the test light does not turn ON, there is an open in the MSM power circuit.
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This test checks the MSM ground circuit. If the test light does not turn ON, there is an open in the MSM power circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Does the scan tool communicate with the MSM? | -- | |||
Select display MSM DTC function with the scan tool. Are any DTCs stored? | -- | Go to Memory Seats System Check or Lumbar Support System Check | ||
Attempt to establish communications with the other modules connected to the same serial data line (PCM, DIM, etc.). Does the scan tool communicate with the other modules? | -- | Go to Scan Tool Does Not Communicate with Class 2 Data Line in Data Link Communications | ||
With a test light connected to ground, probe each memory seat module (MSM) fuse. Does the test lamp light for all fuses? | -- | |||
Does the test lamp light for all circuits? | -- | |||
With a test light connected to battery positive voltage (B+), probe all MSM ground circuits. Does the test lamp light for all circuits? | -- | |||
7 | Repair the open in the battery feed to MSM fuse. If the fuse is open, locate and repair the short to ground in the circuit connected to the open fuse. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
8 | Locate and repair the open in the MSM ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
9 | Locate and repair the open in the MSM power circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
10 | Locate and repair the open in the MSM ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
11 |
Are all DTCs cleared? | -- | -- |
