Component Tests and General Diagnostics
TROUBLESHOOTING HINTSHint 1:
If the engine sometimes stalls, try starting the engine and shaking the volume air flow sensor harness. It the engine then stalls, incorrect or improper contact of the volume air flow sensor connector is the probable cause.
Hint 2:
If the volume air flow sensor output frequency is any value other than zero when the ignition switch is switched ON (but the engine is not started), a malfunction of the volume air flow sensor or of the engine control module is the probable cause.
Hint 3:
If idling is possible even though the volume air flow sensor output frequency is outside the standard value, the cause is usually a malfunction other than of the volume air flow sensor.
[Examples]
(1) The flow of air within the volume air flow sensor is disturbed. (Air duct disconnection or clogged air cleaner element.)
(2) Incomplete combustion inside a cylinder (Malfunction of spark plugs, ignition coil, injectors, compression pressure, etc.)
(3) Air is drawn into the intake manifold through a leaking gasket, etc.
INSPECTION
Using Scan Tool
NOTE: When the vehicle is new [driven approximately 500 km (300 miles) or less], the volume air flow sensor output frequency may be approximately 10% higher than indicated above.
HARNESS INSPECTION
STEP 1. Check for continuity between the volume air flow sensor and the MFI relay.
- MFI relay connector: Disconnected
- Volume air flow sensor connector: Disconnected
NOTE:
- Touch the ohmmeter probes to both ends of the harness.
OK: GO TO STEP 2
NG: Repair the harness. (A4 - B1)
STEP 2. Check for continuity in the ground circuit.
- Volume air flow sensor connector: Disconnected
OK: GO TO STEP 3
NG: Repair the harness. (A5 - 92)
STEP 3. Check for an open or short-circuit between the volume air flow sensor and the engine control module.
- Volume air flow sensor connector: Disconnected
- Engine control module connector: Disconnected
OK: GO TO STEP 4
NG: Repair the harness. (A3 - 90, A7 - 19)
STEP 4. Measure the applied voltage
- Volume air flow sensor connector: Disconnected
- Engine control module connector: Connected
- Ignition switch: ON
Voltage (V): 4.8 - 5.2
OK: STOP
NG: Replace the engine control module.