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Inspection Procedure A-1: Power supply circuit system abnormality of power liftgate control unit.
 
 
cautionBefore replacing the ECU, ensure that the input and output signal circuits are normal.
 
 
 
 
COMMENTS ON TROUBLE SYMPTOM
If the power liftgate control unit functions do not work at all, the power liftgate control unit power supply system, ground system, or power liftgate control unit may have a problem.
 
 
PROBABLE CAUSES
  • Damaged wiring harness and connectors
  • Malfunction of the power liftgate control unit
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Resistance measurement at power liftgate control unit connector (GND1 terminal).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between power liftgate control unit connector (GND1 terminal) and body ground.
OK: Continuity exists (2 Ω or less)
Is the check result normal?
Go to Step 3.
Go to Step 2.
 
STEP 2. Check of open circuit in GND1 line between power liftgate control unit connector and body ground.
Is the check result normal?
Intermittent malfunction (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 3. Voltage measurement at power liftgate control unit connector (BAT2 and IG12 terminal).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the voltage between power liftgate control unit connector (BAT2 terminal) and body ground.
OK: System voltage
(3) Measure the voltage between power liftgate control unit connector (IG12 terminal) and body ground.
OK: System voltage (when electric motor switch is ON)
Is the check result normal?
Go to Step 5.
Go to Step 4.
 
STEP 4. Check of open circuit in BAT2 and IG12 line between power liftgate control unit connector and fusible link.
Is the check result normal?
Intermittent malfunction (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 5. Voltage measurement at power liftgate control unit connector (BAT1 terminal).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the voltage between power liftgate control unit connector (BAT1 terminal) and body ground.
OK: System voltage
Is the check result normal?
Go to Step 7.
Go to Step 6.
 
STEP 6. Check of open circuit in BAT1 line between power liftgate control unit connector and fusible link.
Is the check result normal?
Intermittent malfunction (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 7. System retest
Check that the power liftgate control unit function works normally.
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .)
Replace the power liftgate control unit.