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Inspection Procedure 8: The hazard warning light switch signal is not received.
 
 
cautionWhenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
TECHNICAL DESCRIPTION (COMMENT)
Input signal from the hazard warning light switch is used to operate the functions below. If the signal is abnormal, these functions will not work normally.
  • Keyless entry system (encrypted code registration)
  • Hazard warning light
 
 
TROUBLESHOOTING HINTS
  • The hazard warning light 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: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the hazard warning light switch.
Refer to .
Is the check result normal?
Go to Step 2.
Replace the hazard warning switch.
 
STEP 2. Resistance measurement at hazard warning switch connector (ground terminal)
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the hazard warning switch connector (ground terminal) and ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check of open circuit in ground line between hazard warning switch connector and ground
Is the check result normal?
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.
 
STEP 4. Check of short to power supply, short to ground, and open circuit in HAZ line between ETACS-ECU connector and hazard warning switch connector
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 5. Using scan tool (M.U.T.-III), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect Scan Tool (M.U.T.-III) ."
(2) Check the input signals from the hazard warning switch.
  • Operate the hazard warning switch.
 
Item No.Item nameNormal condition
26Hazard warning light switchOFF to ON (only when switch is operated)
OK: Normal condition is displayed.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU.