P - Charts
Check the Circuit (Power Supply Line) From the Battery to the ETACS-ECUETACS-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
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. 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-114 for damage.
Q: Is ETACS-ECU connector C-114 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.
STEP 3. Check the harness wires between ETACS-ECU connector C-114 and battery.
NOTE: After checking junction block 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.
Q: Are the harness wires between ETACS-ECU connector C-114 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.