Inspection Procedure K-1
INSPECTION PROCEDURE K-1: Flasher timer: Turn-signal lights does not flash when the turn-signal light switch is turned on.
Connectors:
CIRCUIT OPERATION
- The turn-signal light switch sends a signal through the column-ECU (incorporated in the column switch) to the ETACS-ECU. If the column-ECU sends a turn-signal light switch 'ON ' signal to the ETACS-ECU, the ETACS-ECU turns on the flasher timer (incorporated in the ETACS-ECU), thus causing the turn-signal lights to flash.
- The ETACS-ECU operates the turn-signal lights according to the following signals:
- Ignition switch (IG1)
- Turn-signal light switch
TECHNICAL DESCRIPTION (COMMENT)
Is the turn-signal lights do not flash normally, the input circuits from the switches described in 'CIRCUIT OPERATION' or the ETACS-ECU may be defective. If the hazard warning lights do not flash, the power supply line to the ETACS-ECU (dedicated to the turn-signal lights) may be defective.
TROUBLESHOOTING HINTS
- The column switch (turn-signal light and lighting switch) may be defective
- 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 hazard warning light operation.
Q: Do the hazard warning lights work normally?
YES: Go to Step 8
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-319 and junction block connectors C-301, C-308 and C-312 for damage.
Q: Are ETACS-ECU connector C-319 and junction block connectors C-301, C-308 and C-312 in good condition?
YES: Go to step 4.
NO: Repair or replace them. Refer to Harness Connector Inspection. Diagnostic Aids The turn signal lights should flash normally.
STEP 4. Check the harness wires between ETACS-ECU connector 0-319 and junction block connectors 0-301, C-308 and C-312.
Q: Are the harness wires between ETACS-ECU connector C-319 and junction block connectors C-301, 0-308 and C-312 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-319.
(1) Disconnect the ETACS-ECU connector C-319 and measure at the junction block side.
(2) Measure the voltage between terminal 11 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. The turn-signal lights should flash normally.
NO: Go to Step 6.
STEP 6. Check ETACS-ECU connector C-319 for damage.
Q: Is ETACS-ECU connector C-319 in good condition?
YES: Go to Step 7.
NO: Repair or replace it. Refer to Harness Connector Inspection. Diagnostic Aids The turn-signal lights should flash normally.
STEP 7. Check the harness wires between ETACS-ECU connector C-319 and battery.
NOTE: After checking junction block connector C-312 and intermediate connector C-209, check the wires. If junction block connector C-312 and intermediate connector C-209 are damaged, repair or replace them. Refer to Harness Connector Inspection. Diagnostic Aids
Q: Are the harness wires between ETACS-ECU connector C-319 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 MB991 502 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. Refer to. Diagnosis By Symptom
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. Refer to Diagnosis By Symptom