STEP 1. Using scan tool MB991958, check data list item 6: Engine Coolant Temperature Sensor.
caution | To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. |
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the data reading mode for item 6, Engine Coolant Temperature Sensor.- The engine coolant temperature and temperature shown with the scan tool should approximately match.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions . Go to Step 2.
STEP 2. Check harness connector B-11 at engine coolant temperature sensor for damage.
STEP 3. Check the engine coolant temperature sensor.
STEP 4. Measure the sensor supply voltage at engine coolant temperature sensor harness side connector B-11.
(1) Disconnect the connector B-11 and measure at the harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal No. 1 and ground.- Voltage should be between 4.5 and 4.9 volts.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the measured voltage between 4.5 and 4.9 volts?
Go to Step 7. Go to Step 5.
STEP 5. Check harness connector B-26 at ECM for damage.
STEP 6. Measure the sensor supply voltage at ECM connector B-26 by using power plant ECU check harness special tool MB992110.
(1) Disconnect all ECM connectors. Connect the power plant ECU check harness special tool MB992110 between the separated connectors.
(2) Disconnect the engine coolant temperature sensor connector B-11.
(3) Turn the ignition switch to the "ON" position.
(4) Measure the voltage between terminal No. 26 and ground.- Voltage should be between 4.5 and 4.9 volts.
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Is the measured voltage between 4.5 and 4.9 volts?
Repair harness wire between engine coolant temperature sensor connector B-11 (terminal No. 1) and ECM connector B-26 (terminal No. 26) because of open circuit. Then go to Step 11. Go to Step 10.
STEP 7. Check the continuity at engine coolant temperature sensor harness side connector B-11.
STEP 8. Check harness connector B-26 at ECM for damage.
STEP 9. Check for open circuit between engine coolant temperature sensor connector B-11 (terminal No. 2) and ECM connector B-26 (terminal No. 27).
STEP 10. Using scan tool MB991958, check data list item 6: Engine Coolant Temperature Sensor.
STEP 11. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 . (2) Check the diagnostic trouble code (DTC).
Is DTC P0118 set?
Retry the troubleshooting. The inspection is complete.