Circuit/System Testing
- Verify the integrity of the SCIAP and BARO sensors by inspecting for the following conditions:
- Damaged components
- Loose or improper installation
- An air flow restriction
- A cracked or restricted SCIAP sensor vacuum hose
- An intake manifold leak
- Ignition ON, determine which sensor is out of range by comparing SC Inlet Pressure and BARO Sensor kPa parameters with a scan tool.
- Ignition OFF, disconnect the harness connector at the affected sensor.
- Ignition OFF, for 90 seconds test for less than 5 ohms between the low reference circuit terminal A and ground.
- If greater than the specified range, test the low reference circuit terminal A or an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.
- If less than the specified range, test the 5-volt reference 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 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Verify the scan tool sensor parameter is less than 12 kPa.
- If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal C. Verify the scan tool sensor parameter is greater than 95 kPa for the SCIAP sensor, or 199 kPa for the BARO sensor.
- If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- If all circuits test normal, test or replace the affected sensor.