Inspection Procedure O-2

INSPECTION PROCEDURE O-2: The ignition switch (IG1) signal is not sent to the ETACS-ECU.






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
- The ETACS-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.

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 to the ETACS-ECU. Test at ETACS-ECU connector C-319.




1. Disconnect the ETACS-ECU connector C-319 and measure the voltage available at the junction block side of the connector.
2. Turn the ignition switch to the 'ON' position.




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

Q: Is the measured 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 the ETACS-ECU connector C-319 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-319 in good condition?

YES : Go to Step 3.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Diagnostic Aids 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 wiring harness between ETACS-ECU connector C-319 (terminal 8) and ignition switch (IG1).

NOTE: Also check junction block connector C-311 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-311 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Are the wiring harness between ETACS-ECU connector C-319 (terminal 8) and ignition switch (IG1) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. 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.