Retrieving Diagnostic Trouble Codes (DTCs)
- Locate multiplex control unit diagnostic test connector under left side of dash. Turn ignition off. Connect SCS Service Connector (07WAZ-001010A) to multiplex control unit diagnostic test connector and wait for at least 5 seconds.
- Turn ignition on. Observe ignition switch light, ceiling light and buzzer. If ignition switch light and ceiling light does not illuminate, and buzzer does not come on, system is okay. If no DTCs are indicated, but system is known to be abnormal, go to IGNITION SWITCH KEY LIGHT & BUZZER CIRCUIT TEST. If ignition switch light and ceiling light illuminates and buzzer is on, go to next step. NOTE: If only lights or buzzer indicates DTC(s), lights or buzzer is probably faulty. Light and buzzer should flash and beep simultaneously.
- If DTC is present. Light flashing and buzzer beeps (simultaneous) indicate DTC number. See «DTC DIAGNOSIS»(ref-32689-S12627412072001101600000) table. If more than one DTC is present, the system will indicate them in ascending order and will repeat every 3 seconds.
Ignition Switch Key Light/Ceiling Light & Buzzer Circuit Test
Check continuity between diagnostic connector terminal No. 1 (Black wire) and body ground. Check continuity between driver's multiplex control unit terminal B13 (Light Blue wire) and diagnostic connector terminal No. 2 (Light Blue wire). See WIRING DIAGRAMS . If continuity exists, go to next step. If continuity does not exist, repair open in affected circuit. After repairs, recheck for DTCs.
| DTC | Probable Cause |
|---|
| 1 | (1) Door-To-Driver's Multiplex Control Unit |
| 1 | (2) Door Multiplex Control Unit Faulty |
| 1 | (2) Driver's Multiplex Control Unit Faulty |
| 2 | (1) Driver's-To-Passengers Multiplex Control Unit |
| 2 | (2) Driver's Multiplex Control Unit Faulty |
| 2 | (2) Passenger's Multiplex Control Unit Faulty |
| 3 | (1) Passenger's-To-Driver's Multiplex Control Unit |
| 3 | (2) Passenger's Multiplex Control Unit Faulty |
| 3 | (2) Driver's Multiplex Control Unit Faulty |
| (1) Diagnose using COMMUNICATION LINE TESTS. (2) Replace with a known-good control unit and recheck DTCs. |
| (1) | Diagnose using COMMUNICATION LINE TESTS. |
| (2) | Replace with a known-good control unit and recheck DTCs. |
Door-To-Driver's Multiplex Control Unit
- Turn ignition off. Check continuity in communication line between door multiplex control unit harness connector terminal A15 (Brown wire) and driver's multiplex control unit harness connector terminal A2 (Brown wire). See «WIRING DIAGRAMS»(ref-32689-S13880314082001101600000) . If continuity exists, go to next step. If continuity does not exist, repair open in Brown wire. After repairs, recheck DTCs.
- Turn ignition on. Check voltage in communication line between ground and door multiplex control unit harness connector terminal A15 (Brown wire) and driver's multiplex control unit harness connector terminal A2 (Brown wire). See «WIRING DIAGRAMS»(ref-32689-S13880314082001101600000) . Voltage should be 3.5-9.5 volts. If voltage is not as specified, go to next step.
- If voltage is greater than 9.5 volts, check for short in circuit or poor contact or faulty circuit at connector on receiver side of unit. If voltage is less than 3.5 volts, check for short to ground or short to another wire in circuit. Check for poor contact or faulty circuit at connector on transmit side of unit. Repair as necessary. After repairs, recheck DTCs.
Symptoms Of Faulty Wake-Up Communication Line
- An open in a communication line will cause most systems to not operate because one multiplex control unit cannot wake up other multiplex control units. Multiplex control units that are not awake will wake up when a related switch is operated. Turning ignition switch to ON position will wake up all multiplex control units.
- If a communication line is shorted to ground: Most of the systems do not operate because one of the control units will not wake up the other control units. Control unit can wake up by a related switch operation, but other control units cannot wake up by a switch operation. All control units wake up by turning ignition switch to ON position.
