Circuit/System Testing
WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Ignition OFF, disconnect the harness connector at the AIR solenoid.
- Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal 4 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 5-volt reference circuit terminal 3 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 AIR Pressure Sensor parameter is less than 0.5 volts.
- If greater than the specified range, test the signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the ECM.
- Install a 3A fused jumper wire between the signal circuit terminal 2 and the 5-volt reference circuit terminal 3. Verify the scan tool AIR Pressure Sensor parameter is greater than 4.9 volts.
- If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition OFF, connect all wiring harness connectors.
- Ignition ON and engine OFF, observe the AIR Pressure Sensor parameter.
- If the AIR Pressure Sensor parameter does not equal BARO parameter, replace the AIR solenoid valve.
- Engine running, enable the AIR system with a scan tool and observe the AIR Pressure Sensor parameter equals approximately 8-10 kPa above BARO.
- If not within the specified range, continue with this procedure.
- Remove the AIR inlet hose from the AIR pump.
- Engine running, enable the AIR system with a scan tool and observe the AIR Pressure Sensor parameter equals approximately 8-10 kPa above BARO.
- If within the specified range, the AIR pump inlet hoses/pipes are restricted. Remove the restriction or replace the hose/pipe.
- If not within the specified range, continue with this procedure.
- Disconnect the hose from the AIR pump outlet.
- Disconnect the hose quick-connect from the AIR solenoid valve inlet.
- Install a length of standard 1-inch I.D., 25 4-mm, hose from the AIR pump outlet to the AIR solenoid valve inlet.
- Engine RUNNING, enable the AIR system with a scan tool and observe the AIR Pressure Sensor parameter equals approximately 8-10 kPa above BARO.
- If within the specified range, the AIR pump outlet hoses/pipes are restricted or leaking. Remove the restriction or replace the hose/pipe.
- If less than the specified range, replace the AIR pump.
- If more than the specified range, continue with this procedure.
- Remove the AIR solenoid valve.
- Leave the standard hose and harness connector connected.
- Engine running, enable the AIR system with a scan tool and observe the AIR Pressure Sensor parameter increases to approximately 7 kPa above BARO.
- If more than the specified range, replace the AIR solenoid valve.
- If within the specified range, the AIR solenoid valve outlet pipe or the exhaust system is restricted. Remove the restriction or replace the appropriate component.