MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-117
STEP 4. Using scan tool MB991502, check data list item 21:
Engine Coolant Temperature Sensor.
CAUTION
To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991502 to the data reading mode for item
21, 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.
Q: Is the sensor operating properly?
YES :
It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use Troubleshooting/
Inspection Service Points
NO :
Replace the ECM or PCM. Then go to Step 14.
STEP 5. Check connector B-11 at engine coolant
temperature sensor for damage.
Q: Is the connector in good condition?
YES :
Go to Step 6.
NO :
Repair or replace it. Refer to GROUP 00E, Harness
Connector Inspection
. Then go to Step 14.
STEP 6. Check 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 1 and ground.
•
Voltage should be between 4.5 and 4.9 volts.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES :
Go to Step 8.
NO :
Go to Step 7.
AKX01177
16 PIN
MB991502
AB
ACX02490
CONNECTOR : B-11
ENGINE
COOLANT
TEMPERATURE
SENSOR
AC
AK000234
B-11 HARNESS
SIDE CONNECTOR
2 1
AB