Circuit/System Testing

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

Ignition/Vehicle - Off

NOTE:

Additional DTCs will set when disconnecting the components.

Disconnect the electrical connector at one of the following components, depending on the DTC that is set:
P0641
- B1 A/C Refrigerant Pressure Sensor
- B23 Camshaft Position Sensor
- B37B Engine Oil Pressure Sensor
- B75C Multifunction Intake Air Sensor
- B154 Diesel Particulate Filter Exhaust Differential Pressure Sensor
- Q14 Exhaust Gas Recirculation Valve
P0651
- B22 Brake Pedal Position Sensor
- B26 Crankshaft Position Sensor
- B65 Intake Manifold Pressure and Air Temperature Sensor
- M103 Turbocharger Vane Position Actuator
- Q20 Intake Air Flow Valve
- Q85 Cooling Fan Clutch
- R10 Cooling Fan Resistor
P0697
- B107 Accelerator Pedal Position Sensor - Sensor 2
P06A3
- B47B Fuel Rail Pressure Sensor
- B107 Accelerator Pedal Position Sensor - Sensor 1
Ignition - On / Vehicle - In Service Mode
Verify the scan tool parameter: 5V Reference 1 - 4 Circuit Status = Malfunction - For the circuit that set the DTC.
- If not the specified state after disconnecting a component from the circuit
  Test or replace the component: The component that was disconnected last.
- If the specified state and there are components connected to the circuit
  Disconnect a component and repeat step 4.
- Go to next step: If the specified state with all components disconnected from the circuit
Test for 4. 8 to 5. 2 V between the test points:
P0641 - 5V Reference 1 Circuit
- 5 V Reference circuit terminal 2 @ B1 A/C Refrigerant Pressure Sensor & Ground
- 5 V Reference circuit terminal 1 @ B23 Camshaft Position Sensor & Ground
- 5 V Reference circuit terminal 3 @ B37B Engine Oil Pressure Sensor & Ground
- 5 V Reference circuit terminal 2 @ B75C Multifunction Intake Air Sensor & Ground
- 5 V Reference circuit terminal 3 @ B154 Diesel Particulate Filter Exhaust Differential Pressure Sensor & Ground
- 5 V Reference circuit terminal 6 @ Q14 Exhaust Gas Recirculation Valve & Ground
P0651 - 5V Reference 2 Circuit
- 5 V Reference circuit terminal 6 @ B22 Brake Pedal Position Sensor & Ground
- 5 V Reference circuit terminal 1 @ B26 Crankshaft Position Sensor & Ground
- 5 V Reference circuit terminal 3 @ B65 Intake Manifold Pressure and Air Temperature Sensor & Ground
- 5 V Reference circuit terminal 5 @ M103 Turbocharger Vane Position Actuator & Ground
- 5 V Reference circuit terminal 5 @ Q20 Intake Air Flow Valve & Ground
- 5 V Reference circuit terminal E @ Q85 Cooling Fan Clutch & Ground
- 5 V Reference circuit terminal A @ R10 Cooling Fan Resistor & Ground
P0697 - 5V Reference 3 Circuit
- 5 V Reference circuit terminal 1 @ B107 Accelerator Pedal Position Sensor - Sensor 2 & Ground
P06A3 - 5V Reference 4 Circuit
- 5 V Reference circuit terminal 1 @ B47B Fuel Rail Pressure Sensor & Ground
- 5 V Reference circuit terminal 2 @ B107 Accelerator Pedal Position Sensor - Sensor 1 & Ground
- 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:
  P0641
  - 5 V Reference circuit terminal 7 X3 @ Control module harness & Ground
  - 5 V Reference circuit terminal 19 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 40 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 46 X1 @ Control module harness & Ground
  - 5 V Reference circuit terminal 50 X3 @ Control module harness & Ground
  - 5 V Reference circuit terminal 59 X2 @ Control module harness & Ground
  P0651
  - 5 V Reference circuit terminal 21 X3 @ Control module harness & Ground
  - 5 V Reference circuit terminal 43 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 44 X1 @ Control module harness & Ground
  - 5 V Reference circuit terminal 62 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 82 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 83 X2 @ Control module harness & Ground
  P0697
  - 5 V Reference circuit terminal 14 X1 @ Control module harness & Ground
  P06A3
  - 5 V Reference circuit terminal 13 X1 @ Control module harness & Ground
  - 5 V Reference circuit terminal 89 X2 @ Control module 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 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:
  P0641
  - 5 V Reference circuit terminal 7 X3 @ Control module harness & Ground
  - 5 V Reference circuit terminal 19 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 40 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 46 X1 @ Control module harness & Ground
  - 5 V Reference circuit terminal 50 X3 @ Control module harness & Ground
  - 5 V Reference circuit terminal 59 X2 @ Control module harness & Ground
  P0651
  - 5 V Reference circuit terminal 21 X3 @ Control module harness & Ground
  - 5 V Reference circuit terminal 43 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 44 X1 @ Control module harness & Ground
  - 5 V Reference circuit terminal 62 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 82 X2 @ Control module harness & Ground
  - 5 V Reference circuit terminal 83 X2 @ Control module harness & Ground
  P0697
  - 5 V Reference circuit terminal 14 X1 @ Control module harness & Ground
  P06A3
  - 5 V Reference circuit terminal 13 X1 @ Control module harness & Ground
  - 5 V Reference circuit terminal 89 X2 @ Control module 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
- Go to next step: If between 4. 8 and 5. 2 V
All OK.