Inspection Procedure N-4

The ETACS-ECU does not receive any signal from the backup light switch.

Backup Light Switch Input Circuit Part 1:

Backup Light Switch Input Circuit Part 2:

CIRCUIT OPERATION
The ETACS-ECU operates the rear wiper according to signal from the backup light switch.

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the rear wiper does not operate consecutively twice when the shift lever is moved to the "R" position with the rear wiper on. If the signal is not normal, the backup light switch or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- The backup light switch may be defective.
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
- The ETACS-ECU may be defective.

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe




STEP 1. Check backup light switch connector B-111 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is the backup light switch connector B-111 in good condition?

YES: Go to Step 2.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. If the rear wiper operates normally, it indicates that a correct "R" position signal is sent from the backup light switch.







STEP 2. Check the backup light switch.
Disconnect backup light switch connector B-111. Then check continuity between the switch terminals.

Q: Is the backup light switch in good condition?

YES: Go to Step 3.

NO: Replace the backup light switch. If the rear wiper operates normally, it indicates that a correct "R" position signal is sent from the backup light switch.

STEP 3. Check the ignition switch (IG1) circuit to the backup light switch. Measure the voltage at backup light switch connector B-111.




1. Disconnect backup light switch connector B-111 and measure the voltage available at the wiring harness side of the connector.
2. Turn the ignition switch to the "ON" position.




3. Measure the voltage between terminal 1 and ground.
- The voltage should equal approximately 12 volts (battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery positive voltage)?

YES: Go to Step 5.

NO: Go to Step 4.










STEP 4. Check the wiring harness between backup light switch connector B-111 (terminal 1) and the ignition switch (IG1).

NOTE: Also check junction block connectors C-210, C-211, intermediate connectors 6-27and C-123 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connectors C-210, C-211, intermediate connectors 6-27 or C-123 is damaged, Repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between backup light switch connector B-111 (terminal 1) and the ignition switch (IG1) in good condition?

YES: No action is necessary and testing is complete.

NO: The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. If the rear wiper operates normally, it indicates that a correct "R" position signal is sent from the backup light switch.




STEP 5. Check ETACS-ECU connector C-227 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-227 in good condition?

YES: Go to Step 6.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the rear wiper operates normally, it indicates that a correct "R" position signal is sent from the backup light switch.










STEP 6. Check the wiring harness between backup light switch connector B-111 (terminal 2) and ETACS-ECU connector C-227 (terminal 39).

NOTE: Also check joint connector C-23, intermediate connectors 6-27 and C-124 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-23, intermediate connectors 6-27 or C-124 is damaged, Repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between backup light switch connector B-111 (terminal 2) and ETACS-ECU connector C-227 (terminal 39) in good condition?

YES: Replace the ETACS-ECU. If the rear wiper operates normally, it indicates that a correct "R" position signal is sent from the backup light switch.

NO: The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. If the rear wiper operates normally, it indicates that a correct "R" position signal is sent from the backup light switch.