Checking wiring
Check the engine control module (ECM) and mass air flow (MAF) sensor connectors. Check for contact resistance and oxidation according to Contact resistance and oxidation .
Check in particular for damage or loose terminal pins.
Check the signal cable between engine control module (ECM) terminal #16 and mass air flow (MAF) sensor terminal #2. Check for an intermittent short-circuit to ground. according to Short-circuit to ground, intermittent faults . Remedy if necessary.
Check the power supply cable between mass air flow (MAF) sensor terminal #3 and system relay (2/14) terminal #3. Check for an intermittent open-circuit according to Open-circuit, intermittent faults . Remedy if necessary.
The supply voltage should be approximately battery voltage when the system relay is activated.
Check that the idling system air ducts are not blocked.
HINT: If there is a mechanical defect in the idle air control (IAC) valve the air flow may be hindered by blockages in the idling system air ducts.
Check the intake system for air leakage according to intake system/leak test .
Other information:
- To connect the breakout box, see Connecting the breakout box. EMS 2000
- To replace the mass air flow (MAF) sensor, see Replacing the mass air flow (MAF) sensor
- To replace the idle air control (IAC) valve, see Replacing the idle air control (IAC) valve .
- Continue
Refer to Information