Circuit/System Testing
WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition/Vehicle & All vehicle systems » Off
- Disconnect the electrical connector:B47B Fuel Rail Pressure Sensor
- Test for less than 10 Ω between the test points:Low Reference circuit terminal 1 & Ground
- If 10 Ω or greater
- Disconnect the electrical connector: X3 @K20 Engine Control Module
- Test for less than 2 Ω between the test points:Low Reference circuit terminal 1 @Component harness & Terminal 41 @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 3 & Low Reference circuit terminal 1
- If less than 4.8 V
- Ignition/Vehicle » Off
- Disconnect the electrical connector: X3 @K20 Engine Control Module
- Test for infinite resistance between the test points: 5 V Reference circuit terminal 3 @Component harness & Ground
- If less than infinite resistance » Repair the short to ground on the circuit.
- If infinite resistance
- Test for less than 2 Ω between the test points: 5 V Reference circuit terminal 3 @Component harness & Terminal 40 @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 V
- Ignition/Vehicle » Off
- Disconnect the electrical connector: X3 @K20 Engine Control Module
- Ignition » On / Vehicle » In Service Mode
- Test for less than 1 V between the test points: 5 V Reference circuit terminal 3 @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
- Test for 4.8 to 5.2 V between the test points:Signal circuit terminal 2 & Low Reference circuit terminal 1
- If less than 4.8 V
- Ignition/Vehicle » Off
- Disconnect the electrical connector: X3 @K20 Engine Control Module
- Test for infinite resistance between the test points:Signal circuit terminal 2 @Component harness & Ground
- If less than infinite resistance » Repair the short to ground on the circuit.
- If infinite resistance
- Test for less than 2 Ω between the test points:Signal circuit terminal 2 @Component harness & Terminal 60 @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
- Ignition/Vehicle » Off
- Disconnect the electrical connector: X3 @K20 Engine Control Module
- Ignition » On / Vehicle » In Service Mode
- Test for less than 1 V between the test points:Signal circuit terminal 2 @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
- Test or replace the component:B47B Fuel Rail Pressure Sensor
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.