Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the MAF sensor.
- Ignition OFF, allow sufficient time for the ECM to power down. Test for less than 5 ohms of resistance between the low reference circuit terminal D and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition ON, test for 4.8-5.2 volts between the MAF sensor signal circuit terminal A and ground.
- If less than the specified range, test the MAF sensor signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
- If greater than the specified range, test the MAF sensor signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Ignition ON, verify that a test lamp illuminates between the MAF sensor 12-volt reference voltage circuit terminal C and ground.
- If the test lamp does not illuminate, test the 12-volt reference circuit for a short to ground or an open/high resistance.
- Connect the J 38522 to the vehicle. Refer to Component Testing.