Keyless/Power Door Locks (Multiplex Control Unit) Input Test

NOTE: Before testing, troubleshoot the multiplex control system Multiplex Control System Troubleshooting.

1. Remove the driver's dashboard lower cover Driver's Dashboard Lower Cover Removal/Installation.

2. Disconnect under-dash fuse/relay box connectors C, F, J, K, M, P, Q, X, and Y.

NOTE: All connectors are shown from wire side of female terminals.

3. Inspect the connector and socket terminals to be sure they are all making good contact.

- If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system.
- If the terminals look OK, go to step 4.

4. Reconnect all connections to the under-dash fuse/relay box, and do the following input tests:

- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, go to step 5.

5. With the connectors still disconnect, do the following input tests:

- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, the multiplex control unit must be faulty, replace the under-dash fuse/relay box assembly Under-Dash Fuse/Relay Box Removal And Installation.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Keyless/Power Door Locks (Multiplex Control Unit) Input Test

Use the Manual With the Right Hardware

When to See a Mechanic

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