Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

Ignition/Vehicle & All vehicle systems - Off
NOTE: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.
Verify the following conditions do not exist:
- Collapsed or restricted intake air duct.
- Missing, restricted or leaking exhaust components.
- Leaking, missing or damaged O-ring on the components listed below:
  - B74 Manifold Absolute Pressure Sensor
- Engine vacuum leaks.
- An engine mechanical condition. - Wear of timing chain, tensioner or sprockets or if one or more cylinders indicate low compression
  Refer to Symptoms - Engine Mechanical
- If a condition exists - Repair or replace as necessary
- If no condition exists
Disconnect the electrical connector: B74 Manifold Absolute Pressure Sensor
Test for less than 10 Ω between the test points: Low Reference circuit terminal 2 & Ground
- If 10 Ω or greater
1. Disconnect the electrical connector: K20 Engine Control Module
2. Test for less than 2 Ω between the test points: Low Reference circuit terminal 2 @ Component harness & Terminal 5 X2 @ Control module harness
  - If 2 Ω or greater - Repair the open/high resistance in the circuit.
  - If less than 2 Ω - Replace the component: K20 Engine Control Module
- If less than 10 Ω
Ignition - On / Vehicle - In Service Mode
Test for 4.8 to 5.2 V between the test points: 5 V Reference circuit terminal 1 & Low Reference circuit terminal 2
- If less than 4.8 V
1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: K20 Engine Control Module
3. Test for infinite resistance between the test points: 5 V Reference circuit terminal 1 @ Component harness & Ground
  - If less than infinite resistance - Repair the short to ground on the circuit.
  - If infinite resistance
4. Test for less than 2 Ω between the test points: 5 V Reference circuit terminal 1 @ Component harness & Terminal 5 X2 @ Control module harness
  - If 2 Ω or greater - Repair the open/high resistance in the circuit.
  - If less than 2 Ω - Replace the component: K20 Engine Control Module
- If greater than 5.2 V
1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: K20 Engine Control Module
3. Ignition - On / Vehicle - In Service Mode
4. Test for less than 1 V between the test points: 5 V Reference circuit terminal 1 @ Component harness & Ground
  - If 1 V or greater - Repair the short to voltage on the circuit.
  - If less than 1 V - Replace the component: K20 Engine Control Module
- If between 4.8 and 5.2 V
Verify the scan tool parameter: MAP Sensor=Greater than 4.7 V
- If 4.7 V or less
1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: K20 Engine Control Module
3. Test for infinite resistance between the test points: Signal circuit terminal 3 @ Component harness & Ground
  - If less than infinite resistance - Repair the short to ground on the circuit.
  - If infinite resistance - Replace the component: K20 Engine Control Module
- If greater than 4.7 V
Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 3 & Low Reference circuit terminal 2
Verify the scan tool parameter: MAP Sensor =Less than 0.2 V
- If 0.2 V or greater
1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
2. Disconnect the electrical connector: K20 Engine Control Module
3. Ignition - On / Vehicle - In Service Mode
4. Test for less than 1 V between the test points: Signal circuit terminal 3 @ Component harness & Ground
  - If 1 V or greater - Repair the short to voltage on the circuit.
  - If less than 1 V
5. Ignition/Vehicle - Off
6. Test for less than 2 Ω between the test points: Signal circuit terminal 3 @ Component harness & Terminal 40 X3 @ Control module harness
  - If 2 Ω or greater - Repair the open/high resistance in the circuit.
  - If less than 2 Ω - Replace the component: K20 Engine Control Module
- If less than 0.2 V
Test or replace the component: B74 Manifold Absolute Pressure Sensor