For 1990-2009 cars

### 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

### DTC Descriptor

DTC U1401: No Communication with MSM (Memory Seat and Mirror Module)

### Circuit/System Description

The SIM continuously sends a communication signal to the MSM. Upon receiving the signal, the MSM sends a reply signal, confirming that it can communicate.

### Conditions for Running the DTC

The SIM is active.

### Conditions for Setting the DTC

The SIM does not receive a response from the MSM for 10 or more consecutive seconds.

### Action Taken When the DTC Sets

The memory recall function is disabled.

### Conditions for Clearing the DTC

• | The current DTC will clear when the SIM receives a communication reply from the MSM.

• | The history DTC will clear after 50 fault-free ignition cycles have occurred.

### Reference Information

#### Schematic Reference

Driver Seat Schematics .

#### Connector End View Reference

Component Connector End Views .

#### Electrical Information Reference

• | Circuit Testing .

• | Connector Repairs .

• | Testing for Intermittent Conditions and Poor Connections .

• | Wiring Repairs .

#### Scan Tool Reference

Control Module References

### Circuit/System Testing

1. Disconnect the A154 SIM connector, and the A21-X3 MSM connector.
2. Using a DMM test the SIM; position 1, position 2, position 3, mirror dip, UART, module wake-up, power and ground circuits for short to ground or an open/high resistance.

⇒ | If the circuits do not test normal, repair or replace the effected circuit(s).

⇒ | If the circuits test normal, replace the MSM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Memory Seat Control Module Replacement .