Self-Diagnosis Function (Mode 1)

Self-Diagnosis Function (Mode 1):

^ One second after you go into self-diagnosis function mode 1, the function starts to indicate the diagnostic trouble code (DTC), and repeats the DTC every three seconds.
^ From mode 1, disconnect the SCS service connector for five to ten seconds, then reconnect the SCS service connector, and the function goes from mode 1 to mode 2.
^ Make sure the ceiling light switch is in the middle position.

NOTE:
If no DTCs are indicated, but you know the system is abnormal, check these items:
^ If the lights do not come on and buzzer does not beep, check the continuity between the BLK wire of the multiplex control inspection connector and body ground, and check the continuity between the LT BLU wire of the multiplex control inspection connector and multiplex control unit (driver's).
^ If only the lights or the buzzer indicates the DTC(s), the lights or buzzer is probably faulty.

Diagnostic Trouble Code (DTC) Table

NOTE: The numbers in the table show the troubleshooting sequence.

Communication Line Test
1. Continuity Test
Check for continuity according to the table.
^ If there is continuity, go to step 2.
^ If there is no continuity, check for an open in the wire.

2. Voltage Test
A. Turn the ignition switch ON (II).
B. Check for voltage between communication line and ground: The voltage should match the following table.

^ If the voltage is too high:
A. Check for short to another wire.
B. Check for poor contact at the connector on the receiver side unit.
C. Faulty circuit in the receiver side unit.

^ If the voltage is too low:
A. Check for short to ground or to another wire.
B. Check for poor contact at the connector on the transmit side unit.
C. Faulty circuit in the transmitter side unit.
If any control unit appears to be faulty, select one control unit, substitute a known-good control unit, then recheck. If the system works properly, the original control unit is faulty; replace it. If there is still a malfunction, substitute a known-good control unit for another control unit, then recheck. If the system works properly, that control unit is faulty; replace it.