Circuit/System Testing
- Ignition OFF, disconnect the harness connector of the MAP sensor.
- Ignition ON, test for less than 0.2 volt between the low reference circuit and ground.
- If greater than the specified value, test the low reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
- Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit and ground.
- If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
- Ignition ON, load test for 4.8-5.2 volts between the 5-volt reference circuit and ground.
- If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit/connections test normal, replace the ECM.
- If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
- Observe the scan tool MAP sensor pressure parameter. Verify that the MAP sensor parameter is less than 12 kPa.
- If greater than the specified value, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
- Install a 3-amp fused jumper wire between the signal circuit and the 5-volt reference circuit. Verify that the scan tool MAP sensor pressure parameter is greater than 102 kPa.
- If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
- If all circuits/connections test normal, test or replace the MAP sensor.
IMPORTANT:
The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.