Inspection Procedure P-1

INSPECTION PROCEDURE P-1: Check the circuit (power supply line) from the battery to the ETACS - ECU.

ETACS-ECU Power Supply Circuit
Refer to Inspection Procedure A-1 Symptom Procedures.

CIRCUIT OPERATION
The ETACS-ECU is always energized by the battery.

TECHNICAL DESCRIPTION (COMMENT)
If that power supply circuit is defective, the circuit flowing through the ignition switch (IG1) will function as a backup circuit. In this case, the following functions will not work when the ignition switch is at 'LOCK' (OFF) position:
- Ignition key reminder tone alarm function
- Light reminder tone alarm function
- Central door locking system
- Hazard warning light
- Interior light automatic shutoff function
- Interior light dimming function
- Theft-alarm system

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

DIAGNOSIS
Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness

STEP 1. Check the battery power supply circuit to the ETACS-ECU. Test at ETACS-ECU connector C-319.




1. Disconnect the ETACS-ECU connector C-319 and measure the voltage available at the junction block side of the connector.




2. Measure the Voltage between terminal 20 and ground.
- The voltage should equal approximately 12 volts (battery positive voltage).

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

YES : Replace the ETACS-ECU. The functions, which are described in the 'Technical Description (comment),' should work normally.

NO : Go to Step 2.




STEP 2. Check the ETACS-ECU connector C-319 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-319 in good condition?

YES : Go to Step 3.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Diagnostic Aids The functions, which are described in the 'Technical Description (comment),'should work normally.













STEP 3. Check the wiring harness between ETACS-ECU connector C-319 (terminal 20) and battery.

NOTE : Also check junction block connector C-312, joint connector C-141 and intermediate connector C-209 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-312, joint connector C-141 and intermediate connector C-209 are damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection. Diagnostic Aids

Q: Are the wiring harness between ETACS-ECU connector C-319 (terminal 20) and battery 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. The functions, which are described in the 'Technical Description (comment),' should work normally.