Note. Before performing any diagnostic test, refer toWARNINGS, CAUTIONS and NOTES in DIAGNOSTIC TESTS .
Note. Testing individual components does not isolate shorts or opens. Perform all voltage tests using a Digital Volt-Ohmmeter Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.
Diagnostic Aids
Mass Air Flow (MAF) sensor measures amount of air entering the engine. This measurement of airflow is a reflection of engine load (throttle opening). Main input used in fuel injector duration calculation. Located on air intake hose near air cleaner housing. Engine Control Module (ECM) continuously monitors MAF sensor output. ECM will set malfunction code if sensor output voltage has continued to be 4.5 volts or higher for 4 seconds. Check for following possible problems
- Dirty air cleaner.
- Air leak in intake system.
- Contaminated, deteriorated or damaged MAF sensor.
- Poor connection at ECM, MAF sensor or Throttle Position (TP) sensor.
- Faulty MAF sensor or TP sensor.