Circuit/System Testing
WARNING: This page is about a different variant/trim than selected.
NOTE:
- You must perform the Circuit/System Verification before proceeding with the Circuit/System Testing.
- You must perform the Diagnostic Repair Verification after completing the Circuit/System Testing.
- Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B74 Manifold Absolute Pressure Sensor. It may take up to 2 min for all vehicle systems to power down.
- Test for less than 10 Ω between the low reference circuit terminal 1 and ground.
- If 10 Ω or greater
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- If less than 10 Ω
- Ignition ON.
- Test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground.
- If less than 4.8 V
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
- Test for infinite resistance between the 5 V reference circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance
- Test for less than 2 Ω in the 5 V reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
NOTE: If the signal circuit is shorted to a voltage the ECM or the MAP Sensor may be damaged.- If greater than 5.2 V
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
- Test for less than 1 V between the 5 V reference circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- If between 4.8-5.2 V
- Verify the scan tool MAP Sensor voltage parameter is greater than 4.8 V.
- If 4.8 V or less
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
- Test for infinite resistance between the signal circuit terminal 4 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K20 Engine Control Module.
- If greater than 5.2 V
- Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 1.
- Verify the scan tool MAP Sensor voltage parameter is less than 0.2 V.
- If 0.2 V or greater
- Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
- Test for less than 1 V between the signal circuit terminal 4 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V
- Ignition OFF
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- If less than 0.2 V
- Test or replace the B74 Manifold Absolute Pressure Sensor.