MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-158
STEP 1. Using scan tool MB991502, check data list item 69:
Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).
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) Start the engine and run at idle.
(3) Set scan tool MB991502 to the data reading mode for item
69, Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).
•
Warming up the engine. When the engine is revved, the
output voltage should repeat 0 volt and 0.6 to 1.0 volt
alternately.
(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 :
Go to Step 2.
STEP 2. Check the sensor output voltage at right bank
heated oxygen sensor (rear) connector B-28 by
backprobing.
(1) Do not disconnect the connector B-28.
(2) Start the engine and run at idle.
(3) Measure the voltage between terminal 4 and ground by
backprobing.
•
Warming up the engine. When the engine is revved, the
output voltage should repeat 0 volt and 0.6 to 1.0 volt
alternately.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES :
Go to Step 3.
NO :
Go to Step 7.
AKX01177
16 PIN
MB991502
AB
AKX01538
1 2
3 4
AD
B-28 CONNECTOR
HARNESS
SIDE VIEW
