Air Flow Meter/Sensor: Testing and Inspection
MASS AIR FLOW (MAF) SENSOR INSPECTIONNOTE: Perform the following test only when directed.
1. Visually inspect for damage, cracks, terminal bends and terminal rust on the MAF sensor.
- If any of the above are found, replace the MAF sensor.
- If the MAF sensor is okay, but PID value or PCM terminal 3E voltage are out of specification, carry out the "Circuit Open/Short Inspection".
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Connect the SST (ESM adapter harness) between the PCM and the vehicle harness connectors.
3. Inspect for an open or short circuit in the following wiring harnesses by probing the applicable sensor and SST (ESM adapter harness) terminals with ohmmeter leads.
- If there is an open or short circuit, repair or replace wiring harnesses.
- If there is no open or short circuit, replace the MAF sensor.
Open circuit
- MAF signal circuit (MAF sensor connector terminal B and PCM connector terminal 3E)
- Power circuit (MAF sensor connector terminal C and main relay terminal D through common connector)
- GND circuit (MAF sensor connector terminal A and PCM connector terminal 4D through common connector)
Short circuit
- MAF signal circuit (MAF sensor connector terminal B and PCM connector terminal 3E to GND)
- Power circuit (MAF sensor connector terminal C and main relay terminal D through common connector to GND)
4. Reconnect the MAF sensor connector.
Specification:
NOTE: The scan tool shows the MAF rate and load value.