Inspection Procedure O-2

The ignition switch (IG1) signal is not sent to the ETACS-ECU.

Ignition Switch (IG1) Input Circuit:

CIRCUIT OPERATION
- The ETACS-ECU operates various functions according to the input signal from the ignition switch (IG1).
- This circuit will work as a backup circuit if the battery circuit to the ETACS-ECU is open circuit.

TECHNICAL DESCRIPTION (COMMENT)
The ignition switch (IG1) input signal is used to operate the following devices or functions:
- Ignition key reminder tone alarm function
- Light reminder tone alarm function
- Door ajar tone alarm function
- Low washer fluid level tone alarm function
- Seat belt tone alarm function
- Low fuel level tone alarm function
- Rolling lock function
- Power window timer function
- Sunroof timer function
- Low washer fluid level warning light
- Seat belt warning light
- Headlight automatic shutdown function
- Turn-signal light
- Interior light dimming function

If the signal fails, these devices will not work normally.

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 ignition switch (IG1) circuit at the ETACS-ECU connector C-311.
1. Disconnect the ETACS-ECU connector C-311 and measure at the junction block side.
2. Turn the ignition switch to the "ON" position.




3. Measure the voltage between terminal 11 and ground.

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

YES: Replace the ETACS-ECU. The ignition switch (IG1) input signal should be able to be checked and 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 for 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 ignition switch (IG1) input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.




STEP 3. Check the harness wires between ETACS-ECU connector C-311 and ignition switch (IG1).






NOTE: After checking junction block connector C-301, check the wires. If junction block connector C-301 is damaged, repair or replace it. Refer to Harness Connector Inspection.

Q: Are the harness wires between ETACS-ECU connector C-311 and Ignition switch (IG1) In good condition?

YES: There is no action to be taken.
NO: Repair them. The ignition switch (IG1) input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.