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.

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 dimming function Theft-alarm system

TROUBLESHOOTING HINTS
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

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

STEP 1. Check the battery circuit at the ETACS-ECU connector C-311.
1. Disconnect the ETACS-ECU connector C-311 and measure at the junction block side.




2. Measure the Voltage between terminal 2 and ground.

Q: Is the 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 ETACS-ECU connector C-311 or damage.

Q: Is ETACS-ECU connector C-311 in good condition?

YES: Go to Step 3.
NO: Repair or replace it. Refer to Harness Connector Inspection. The functions, which are described in the "Technical Description (comment)," should work normally.

ETACS-ECU Terminal Arrangement:

STEP 3. Check the harness wires between ETACS-ECU connector C-311 and battery.












NOTE: After checking junction block connector C-310, joint connector C-141 and intermediate connector C-209, check the wires. If junction block connector C-310, joint connector C-141 and intermediate connector C-209 are damaged, repair or replace them. Refer to Harness Connector Inspection.

Q: Are the harness wires between ETACS-ECU connector C-311 and battery in good condition?

YES: There is no action to be taken.
NO: Repair them. The functions, which are described in the "Technical Description (comment)," should work normally.