Inspection Procedure J-5
INSPECTION PROCEDURE J-5: Headlight, Taillight: Headlight automatic shutdown function does not work normally.
TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU and front-ECU operates the headlight automatic shutdown function, based on the signals from the following switches:
- Ignition switch (IG1)
- Taillight switch
- Headlight switch
If the function does work normally, a defect on relevant input circuits, the ETACS-ECU or the front-ECU is suspected.
TROUBLESHOOTING HINTS
- The column switch (turn-signal light and lighting switch) may be defective
- The ETACS-ECU may be defective
- The front-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 DTC.
Q: Does the DTC set when the ignition switch is turned to the "LOCK" (OFF) position?
YES : Carry out the troubleshooting by referring to Diagnostic Trouble Code Chart. Trouble Code Diagnostic Charts
NO : Go to Step 2
STEP 2. Check the input signal (by using scan tool MB991502).
Check the input signals from the following switches.
- Ignition switch (IG1)
- Driver's door switch
- Taillight switch
- Headlight 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 : Go to Step 4.
NO :
- The voltmeter needle does not fluctuate when the ignition switch is turned from "ACC" to "ON": Refer to Inspection Procedure O-2 "The ignition switch (IG1) signal is not sent to the ETACS-ECU." Inspection Procedure O-2
- The voltmeter needle does not fluctuate when the driver's door is opened: Refer to Inspection Procedure O-8 "The driver's or passenger's door switch signal is not sent to the ETACS-ECU." Inspection Procedure O-8
- The voltmeter needle does not fluctuate when the lighting switch is turned from "OFF" to "TAIL": Refer to Inspection Procedure O-14 "The taillight switch signal is not sent to the ETACS-ECU." Inspection Procedure O-14
- The voltmeter needle does not fluctuate when the lighting switch is turned from "TAIL" to "HEAD": Refer to Inspection Procedure O-14 "The headlight switch signal is not sent to the ETACS-ECU." Inspection Procedure O-14
STEP 3. Check the input signal (by using a voltmeter).
Check the input signals from the following switches.
- Ignition switch (IG1)
- Driver's door switch
- Taillight switch
- Headlight 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 : Go to Step 4.
NO :
- Scan tool MB991502 does not sound when the ignition switch is turned from "ACC" to "ON": Refer to Inspection Procedure O-2 "The ignition switch (IG1) signal is not sent to the ETACS-ECU." Inspection Procedure O-2
- Scan tool MB991502 does not sound when the driver's door is opened: Refer to Inspection Procedure O-8 "The driver's or passenger's door switch signal is not sent to the ETACS-ECU." Inspection Procedure O-8
- Scan tool MB991502 does not sound when the lighting switch is turned from "OFF" to "TAIL": Refer to Inspection Procedure O-14 "The taillight switch signal is not sent to the ETACS-ECU." Inspection Procedure O-14
- Scan tool MB991502 does not sound when the lighting switch is turned from "TAIL" to "HEAD": Refer to Inspection Procedure O-14 "The headlight switch signal is not sent to the ETACS-ECU." Inspection Procedure O-14
STEP 4. Replacement of ECU.
1. Replace the front-ECU.
2. The headlight automatic shutdown function should work normally.
Q: Is the headlight automatic shutdown function working normally?
YES : No action is necessary and testing is complete.
NO : Replace the ETACS-ECU. The headlight automatic shutdown function should work normally.