STEP 1. Using scan tool MB991958, check data list item 52: Fuel Tank Differential Pressure 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) Disconnect hose D from the evaporative emission canister, and plug the hose.
(3) Turn the ignition switch to the "ON" position.
(4) Remove the fuel cap.
(5) Set scan tool MB991958 to the data reading mode for item 52, Fuel Tank Differential Pressure Sensor.- Output voltage should be between 1,500 and 3,500 millivolts.
(6) Connect the evaporative emission system pressure pump (Miller number 6872A) to the fuel tank filler tube by using fuel tank adapter (MLR-8382) and pressurize the fuel tank.- The fuel tank pressure reading should increase.
(7) Turn the ignition switch to the "LOCK" (OFF) position.
(8) Remove the evaporative emission system pressure pump (Miller number 6872A) and the fuel tank adapter (MLR-8382), and reinstall the fuel cap.
(9) Connect hose D to the evaporative emission canister.
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.