Inspection Procedure O-2

The ETACS-ECU does not Receive Any Signal from the Ignition Switch (IG1).

Ignition Switch (IG1) Input Circuit Part 1:

Ignition Switch (IG1) Input Circuit Part 2:

CIRCUIT OPERATION
- The ETACS-ECU operates the following equipment or functions according to signal from the ignition switch (IG1):
- Ignition key reminder tone alarm function
- Light reminder tone alarm function
- Seat belt tone alarm function
- Power window timer function
- Seat belt warning light
- Headlight automatic shutdown function
- Turn-signal light
- Dome light dimming function

- If the power supply circuit from the battery to the ETACS-ECU is open, this circuit is used as backup circuit.

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the equipment or functions, which are described in "CIRCUIT OPERATION", do not work normally.

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

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface
- MB991827: MUT-III USB cable
- MB991911: MUT-III Main harness B

STEP 1. Measure at ETACS-ECU connector C-119 in order to check the line from the ignition switch (IG1) to the ETACS-ECU.




1. Disconnect ETACS-ECU connector C-119, and measure at the junction block side.
2. Turn the ignition switch to the "ON" position.




3. Measure the voltage between terminal 8 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).

Q: Does the measured voltage correspond with this range?

YES: Replace the ETACS-ECU. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the ignition switch (IG1) should be normal.

NO: Go to Step 2.




STEP 2. Check ETACS-ECU connector C-119 for damage.

Q: Is ETACS-ECU connector C-119 in good condition?

YES: Go to Step 3.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the ignition switch (IG1) should be normal.







STEP 3. Check the wiring harness between ETACS-ECU connector C-119 (terminal 8) and the ignition switch (IG1).

NOTE: Also check junction block connector C-111. If junction block connector C-111 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between ETACS-ECU connector C-119 (terminal 8) and ignition switch (IG1) in good condition?

YES: No action to be taken.

NO: Repair the wiring harness. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the ignition switch (IG1) should be normal.