Circuit/System Testing

WARNING: This page is about a different car, the 2020 Buick Regal and 2019 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

Ignition/Vehicle & All vehicle systems - Off
Disconnect the appropriate electrical connector: B52 Heated Oxygen Sensor
Ignition - On / Vehicle - In Service Mode & Engine - Off
Test for 1.5 to 3.0 V between the test points: Signal circuit terminal 4 & Ground
- If less than 1.5 V
1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: X2 @ K20 Engine Control Module
3. Test for infinite resistance between the test points: Signal circuit terminal 4 & Ground
  - If less than infinite resistance - Repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
4. Test for less than 2 ohms between the test points: Signal circuit terminal 4 @ Component harness & 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 - Test or replace the component: K20 Engine Control Module
- If greater than 3.0 V
1. Ignition/Vehicle - Off
2. Disconnect the electrical connector: X2 @ 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 4 & 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 1.5 and 3.0 V
Verify the scan tool parameter:
- HO2S Bank 1 Sensor 1 = 1.5 to 2.1 V
- HO2S Bank 1 Sensor 2 = 1.5 to 2.1 V
- HO2S Bank 2 Sensor 1 = 1.5 to 2.1 V
- HO2S Bank 2 Sensor 2 = 1.5 to 2.1 V
- If less than 1.5 V
1. Ignition/Vehicle - Off
2. Disconnect the appropriate electrical connector: X2 @ 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
- Go to next step: If between 1.5 and 2.1 V
Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 4 & Signal circuit terminal 3
Verify the scan tool parameter:
- HO2S Bank 1 Sensor 1 = 0.0 V
- HO2S Bank 1 Sensor 2 = 0.0 V
- HO2S Bank 2 Sensor 1 = 0.0 V
- HO2S Bank 2 Sensor 2 = 0.0 V
- If greater than 0.0 V
1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
2. Disconnect the electrical connector: X2 @ 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.
  - 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 3 @ Component harness & 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 0.0 V
Verify the following conditions do not exist:
- B52 Heated Oxygen Sensor - Water intrusion @ Harness Connector
- Evaporative Emission Canister - Saturated with fuel
- Exhaust System - Leaking
- Fuel - Contaminated/Poor Quality - Refer to: Alcohol/Contaminants-in-Fuel Diagnosis
- Fuel Pressure - High/Low - Refer to: Fuel System Diagnosis
- Vacuum leak @ Engine/Hoses / Lines
- If a condition exists
  Repair or replace as necessary
- Go to next step: If no conditions exist
Test or replace the component: B52 Heated Oxygen Sensor