P - Charts

ETACS-ECU Power Supply And Scan Tool Communication Circuit:

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.
- Light reminder tone alarm function
- Ignition key reminder tone alarm function
- Central door locking system
- Hazard warning light
- Dome 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-114.
1. Disconnect the ETACS-ECU connector C-114 and measure at the junction block side.
2. Voltage between terminal 2 and ground.
- Voltage should be approximately 12 volts (system voltage).
If not approximately 12 volts, go to Step 2.
If approximately 12 volts, replace the ETACS-ECU.
The functions, which are described in the "Technical Description (comment)," should work normally.

STEP 2. Check the ETACS-ECU connector C-114 for damage.
If the ETACS-ECU connector C-114 is damaged, repair or replace it. Refer to Harness Connector Inspection.
The functions, which are described in the "Technical Description (comment)," should work normally.
If the connector is in good condition, go to Step 3.

STEP 3. Check the harness wires between ETACS-ECU connector C-114 and battery.

NOTE: After checking joint connector C-78 and intermediate connector C-89, check the wires. If joint connector C-78 and intermediate connector C-89 are damaged, repair or replace them. Refer to Harness Connector Inspection.

If the harness wires between ETACS-ECU connector C-114 and battery are damaged, repair them.
The functions, which are described in the "Technical Description (comment)," should work normally.