Inspection Procedure K-1

Flasher timer: Turn-signal lights does not flash when the turn-signal light switch is turned on.

Turn-Signal Lights Drive Circuit:

Connectors:

CIRCUIT OPERATION
If the ETACS-ECU receives a signal from the turn-signal light switch, the flasher timer circuit (which is incorporated in the ETACS-ECU) marks the turn-signal lights flash.

TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU makes the turn-signal lights flash, based on the input signals from the following switches:
- Ignition switch (IG1)
- Turn-signal light switch

If the turn-signal lights do not flash normally, a defect on the relevant circuits or the ETACS-ECU may be suspected.

If the hazard warning lights also do not flash, a defect in the ETACS-ECU power supply line specific to the turn-signal lights is suspected.

NOTE: If only one of the turn-signal lights does not flash, the light bulb may be burned out or the harness wires between the ETACS-ECU and the light may be defective. In this case, check the circuit by referring to Turn-signal Light and Hazard Warning Light.

TROUBLESHOOTING HINTS
- Malfunction of the column switch (turn-signal light and lighting switch)
- 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 hazard warning light operation.

Q: Do the hazard warning lights work normally?

YES: Go to Step 8 or 9 .
NO: Go to Step 2.

STEP 2. Check turn-signal light state operation.

Q: Does any turn-signal lights flash?

YES (only one side illuminates): Go to Step 3.
NO (no lights flash at all): Go to Step 5.

STEP 3. Check ETACS-ECU connector C-311 and junction block connectors C-303, C-308 and C-310 for damage.

Q: Are ETACS-ECU connector C-311 and junction block connectors C-303, C-308 and C-310 in good condition?

YES: Go to Step 4.
NO: Repair or replace them. Refer to Harness Connector Inspection. The turn-signal lights should flash normally.

STEP 4. Check the harness wires between ETACS-ECU connector C-311 and junction block connectors C-303, C-308 and C-310.

Q: Are the harness wires between ETACS-ECU connector C-311 and Junction block connectors C-303, C-308 and C-310 in good condition?

YES: Replace the ETACS-ECU. The turn-signal lights should flash normally.
NO: Repair them. The turn-signal lights should flash normally.

STEP 5. Check the ETACS-ECU power supply circuit (for turn-signal light) at the ETACS-ECU connector C-311.
1. Disconnect the ETACS-ECU connector C-311 and measure at the junction block side.

2. Measure the voltage between terminal 18 and ground.

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

YES: Replace the ETACS-ECU. The turn-signal lights should flash normally.
NO: Go to Step6.

STEP 6. Check ETACS-ECU connector C-311 for damage.

Q: Is ETACS-ECU connector C-311 in good condition?

YES: Go to Step 7.
NO: Repair or replace it. Refer to Harness Connector Inspection. The turn-signal lights should flash normally.

STEP 7. Check the harness wires between ETACS-ECU connector C-311 and battery.

NOTE: After checking junction block connector C-308 and intermediate connector C-209, check the wires. If junction block connector C-308 and intermediate connector C-209 are damaged, repair or replace them. Refer to Harness Connector Inspection.

Q: Are the harness wires between ETACS-ECU connector C-311 and battery in good condition?

YES: There is no action to be taken.
NO: Repair them. The turn-signal lights should flash normally.

STEP 8. Check the input signal (by using scan tool MB991502).
Check the input signals from the following switches.
- Ignition switch (IG1)
- Turn-signal light switch

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.

1. Connect scan tool MB991502 to the data link connector.
2. Check that the tone alarm of scan tool MB991502 sounds when the input signal enters.

Q: Does the tone alarm of scan tool MB991502 sound when the input signal enters?

YES: Replace the ETACS-ECU. The turn-signal lights should flash normally.
NO: Check the relevant input signal circuit.

STEP 9. Check the input signal (by using a voltmeter).
Check the input signals from the following switches.
- Ignition switch (IG1)
- Turn-signal light switch

1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. Check that the voltmeter indicator deflects once when the input signal enters.

Q: Does the voltmeter indicator deflect?

YES: Replace the ETACS-ECU. The turn-signal lights should flash normally.
NO: Check the relevant input signal circuit.