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Inspection Procedure 14: Seat belt reminder function does not work normally.
 
 
cautionBefore replacing the combination meter, be sure to check that the power supply circuit, ground circuit, and communication circuit are normal.
 
 
 
 
TECHNICAL DESCRIPTION (COMMENT)
If the seat belt reminder function does not work normally, the seat belt switch input circuit, the combination meter or passenger’s air bag OFF indicator light assembly may be defective.
 
 
TROUBLESHOOTING HINTS
  • The seat belt switch (driver’s side) may be defective.
  • The seat belt switch (passenger’s side) may be defective.
  • The combination meter may be defective.
  • The passenger’s air bag OFF indicator light assembly 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. Using scan tool (M.U.T.-III), diagnose the CAN bus line
(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 the Scan Tool (M.U.T.-III) ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).
 
STEP 2. Using scan tool (M.U.T.-III), read the SRS diagnostic trouble code.
Check if DTC is stored in the SRS-ECU.
Is the DTC stored?
Diagnose the SRS-ECU (Refer to GROUP 52B - Troubleshooting ).
Go to Step 3.
 
STEP 3. Check the seat belt switch.
Refer to GROUP 52A - Front Seat Belt .
Is the check result normal?
Go to Step 4.
Replace the seat belt switch.
 
STEP 4. Resistance measurement at the seat belt switch (driver’s side) connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the seat belt switch (driver’s side) connector and ground.
OK: The resistance should be 2 ohms or less.
Is the check result normal?
Go to Step 6.
Go to Step 5.
 
STEP 5. Check of open circuit in ground line between seat belt switch (driver’s side) and ground.
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 ).
Repair the wiring harness.
 
STEP 6. Check of short to power supply circuit in S/B- line between combination meter connector and seat belt switch (driver’s side) connector.
Is the check result normal?
Go to Step 7.
Repair the connector(s) or wiring harness.
 
STEP 7. Check of short to power supply, and open circuit in BWLP line between combination meter connector and passenger’s air bag OFF indicator light assembly connector.
Is the check result normal?
Go to Step 8.
Repair the connector(s) or wiring harness.
 
STEP 8. Retest the system.
The seat belt reminder function should work normally.
Is the check result normal?
<The seat belt reminder function works normally.> : The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
<Tone alarm sounds do not sound.> : Replace the combination meter.
<The indicator (driver’s side) does not illuminate.> : Replace the combination meter.
<The indicator (passenger’s side) does not illuminate.> : Replace the passenger’s air bag OFF indicator light assembly.