Engine Controls - MIL ON, Sporadic Intake Air Faults

24 12 10

December 20, 2012

2031855





Vehicle Information

Condition

MIL- ON Sporadic Intake Air Faults

Technical Background

Completion of the MAF sensor (G70) function test is important to ensure proper diagnosis. Sporadic faults can be caused from loose wiring connections, unsecure terminals, corrosion or damaged wires.

Production Solution

N/A

Service

Note:

A completed MAF sensor (G70) test is required for reimbursement.

^ The following points as described in the function test must be verified.

^ Check Air filter for contamination.
^ Verify correct MAF sensor (G70) is installed.
^ Oil filler cap is secure.
^ Oil dipstick seals are in good condition and secures tight.
^ All intake hoses and crankcase breather are inspected for leaks or deformations.

^ Perform a MAF sensor (G70) function test.

Scenario 1

^ Following completion of the MAF sensor (G70) function test in guided fault finding, switch OFF the engine and disconnect the connection to the MAF sensor (G70). Carefully inspect the connector for backed out terminals in the connector housing. If found, re-seat terminals, clear codes, and road test. Repair complete.

Scenario 2

^ If no backed out terminals are found, check for any signs of corrosion, spread terminals (confirm with pin drag test). If corrosion or spread terminals are found, re-pin connector housing, clear codes, and road test. Repair complete.

Scenario 3

^ If there are no signs of the above mentioned, re-secure the connector to the MAF sensor (G70).

^ Start the engine.

^ Make sure the vehicle has reached at least 80C operating temperature, and all consumer electrics are switched OFF.

^ Select MVB 2, field 4, in the VAS tester.

^ Move the connector back and forth (wiggle) and compare the readings to the specified values (2.0 g/s - 5.0 g/s). Repeat back and forth movement several times to confirm connection is secure.

^ If the readings exceed the specified values or become erratic, re-pin the MAF sensor (G70) wiring harness connector terminals in the connector. See Repair Manual Group 97 in ElsaWeb. Clear codes, and road test. Repair complete.

^ If the readings do not exceed the specified values, this bulletin does not apply. Continue to further diagnose the electrical system as described in the repair manual, located under the headings: Engine -> Generic scan tool -> Diagnosis and testing -> Diagnostic procedures -> MAF sensor, checking.














Warranty





Required Parts and Tools

Additional Information

All part and service references provided in this Technical Bulletin are subject to change and/or removal.
Always check with your Parts Dept. and Repair Manuals for the latest information.