Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT5. However, it is still accessible from the selected car via links, so may be relevant.

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.

Ignition/Vehicle & All vehicle systems - Off
Disconnect the electrical connector: X131 Inline Harness Connector

NOTE:

Testing for steps 3 to 7 is performed on the control module K20 side of the harness connector.

Test for less than 10 ohms between the test points: Low Reference circuit terminal 2@X131 Inline Harness Connector & Ground
- If 10 ohms or greater
1. Disconnect the electrical connector: X2@K20 Engine Control Module
2. Test for less than 2 ohms between the test points: Low Reference circuit terminal 2@X131 Inline Harness Connector & The other end of the circuit@Control module harness
  - If 2 ohms or greater - Repair the open/high resistance in the circuit.
  - If less than 2 ohms - Replace the component: K20 Engine Control Module
- Go to next step: If less than 10 ohms
Ignition - On/Vehicle - In Service Mode
Verify the scan tool parameter: Engine Coolant Temperature Sensor = Colder than -39°C (-38°F)
- If warmer than -39°C (-38°F)
1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: X4@K20 Engine Control Module
3. Test for infinite resistance between the test points: Signal circuit terminal 1@X131 Inline Harness Connector & Ground
  - If less than infinite resistance - Repair the short to ground on the circuit.
  - If infinite resistance - Replace the component: K20 Engine Control Module
- Go to next step: If colder than -39°C (-38°F)
Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 1 & Low Reference circuit terminal 2@X131 Inline Harness Connector
Verify the scan tool parameter: Engine Coolant Temperature Sensor = Warmer than 139°C (282°F)
- If 139°C (282°F) or colder
1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
2. Disconnect the electrical connector: X4@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 1@X131 Inline Harness Connector & Ground
  - If 1 V or greater - Repair the short to voltage on the circuit.
  - Go to next step: If less than 1 V
5. Ignition/Vehicle - Off
6. Test for less than 2 ohms between the test points: Signal circuit terminal 1@X131 Inline Harness Connector & Terminal 61 X4@Control module harness
  - If 2 ohms or greater - Repair the open/high resistance in the circuit.
  - If less than 2 ohms - Replace the component: K20 Engine Control Module
- Go to next step: If warmer than 139°C (282°F)
Disconnect the electrical connector: B34 Engine Coolant Temperature Sensor
Connect the electrical connector: X131 Inline Harness Connector
Ignition - On/Vehicle - In Service Mode
Verify the scan tool parameter: Engine Coolant Temperature Sensor = Colder than -39°C (-38°F)
- If warmer than -39°C (-38°F)
  Replace the component: X131Component harness
- Go to next step: If colder than -39°C (-38°F)
Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 2 & Low Reference circuit terminal 1@B34 Engine Coolant Temperature Sensor
Verify the scan tool parameter: Engine Coolant Temperature Sensor = Warmer than 139°C (282°F)
- If colder than 139°C (282°F)
  Replace the component: X131Component harness
- Go to next step: If warmer than 139°C (282°F)
Test or replace the component: B34 Engine Coolant Temperature Sensor