Inspection Procedure O-7

Column Switch: ETACS-ECU Does Not Receive Any Signal From The Taillight Switch, The Headlight Switch, The Passing Light Switch, The Dimmer Switch, The Turn-signal Light Switch Or Switch.

NOTE: This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, refer to "How to use SWS monitor."

Turn-signal Light And Lighting Switch Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates the following equipment or functions according to signal from the column switch (turn-signal light and lighting switch):
- Light reminder tone alarm function
- Headlight
- Turn-signal light

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the equipment or functions, which are described in "CIRCUIT OPERATION", do not work normally. If the signal is not normal, the column switch (turn-signal light and lighting switch) or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- Malfunction of column switch (turn-signal light and lighting switch)
- Malfunction of the ETACS-ECU
- Damaged harness wipes or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991862: SWS Monitor Kit

STEP 1. Use scan tool to select "ECU COMM CHECK" on the SWS monitor display.
Check the column-ECU.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502. Also connect SWS monitor kit MB991862 after turning on scan tool MB991502.







1. Connect scan tool MB991502 to the data link connector.
2. Connect SWS monitor kit MB991862 to the column switch connector.
3. Turn the ignition switch to the "LOCK" (OFF) position.
4. Operate the MUT-II according to the procedure below to display "ECU COMM CHECK."
1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. Select "ECU COMM CHECK."
5. Scan tool MB991502 should show "OK" on the "ECU COMM CHECK" menu.

Q: Is "OK" displayed on the "COLUMN ECU" menu?

YES: Go to Step 2.

NO: Refer to Inspection Procedure A-2 "Communication with column switch (column-ECU) is impossible."







STEP 2. Check the turn-signal light and lighting switch.
Remove the turn-signal light and the lighting switch.Then check continuity between the switch terminals.

Q: Is the turn-signal light and lighting switch in good condition?

YES: Go to Step 3.

NO: Replace it. The input signal from the column switch (turn-signal light and lighting switch) should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.

STEP 3. Replacement of ECU.

1. Replace the column switch.
2. The input signal from the column switch (turn-signal light and lighting switch) should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.

Q: Is the input signal from the column switch (turn-signal light and lighting switch) input normally?

YES: There is no action to be taken.

NO: Replace the ETACS-ECU. The input signal from the column switch (turn-signal light and lighting switch) should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.