Circuit/System Testing
WARNING: This page is about a different variant/trim than selected.
- Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at the B74 manifold absolute pressure sensor. It may take up to 2 minutes for all vehicle systems to power down.
- Test for less than 2 Ω between the low reference circuit terminal A or 2 and ground.
- If 2 Ω or greater
- Ignition OFF, disconnect the X2 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 2 Ω
- Ignition ON.
- Test for 4.8-5.2 V between the 5 V reference circuit terminal C or 1 and ground.
- If less than 4.8 V
- Ignition OFF, disconnect the X2 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.
- If greater than 5.2 V
NOTE:If the signal circuit is shorted to a voltage the engine control module or the sensor may be damaged.
- Ignition OFF, disconnect the X2 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 voltage parameter is less than 0.2 V.
- If 0.2 V or greater
- Ignition OFF, disconnect the X2 harness connector at the K20 engine control module, ignition ON.
- Test for less than 1 V between the signal circuit terminal B or 3 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 less than 0.2 V
- Install a 3 A fused jumper wire between the signal circuit terminal B or 3 and the 5 V reference circuit terminal C or 1.
- Verify the scan tool MAP voltage parameter is greater than 4.5 V.
- If 4.5 V or less
- Ignition OFF, remove the jumper wire, disconnect the X2 harness connector at the K20 engine control module.
- Test for infinite resistance between the signal circuit terminal B or 3 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 signal circuit end to end.
- If 2 Ω or greater, repair the open or high resistance in the circuit.
- If less than 2 Ω, replace the K20 engine control module.
- If greater than 4.5 V
- Test or replace the B74 manifold absolute pressure sensor.