Circuit/System Testing
WARNING: This page is about a different variant/trim than selected.
- Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate B52 Heated Oxygen Sensor. It may take up to 2 min for all vehicle systems to power down. Ignition ON.
- Test for 1.7-3.0 V between the high signal circuit terminal 4 and ground.
- If less than 1.7 V
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
- Test for infinite resistance between the high signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance
- Test for less than 2 Ω in the high signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- If greater than 3.0 V
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
- Test for less than 1 V between the high signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- If between 1.7-3.0 V
- Verify the scan tool heated oxygen sensor Bank 1 or 2 Sensor 1 or 2 parameter is between 1.7-2.1 V.
- If less than 1.7 V
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
- Test for infinite resistance between the low signal circuit terminal 3 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K20 Engine Control Module.
- If between 1.7-2.1 V
- Connect a 3 A fused jumper wire between the high signal circuit terminal 4 and the low signal circuit terminal A.
- Verify the scan tool heated oxygen sensor Bank 1 or 2 Sensor 1 or 2 parameter displays 0.0 V.NOTE: The low signal circuit is tied to a pull-up circuit within the engine control module. A voltage of 0.0-1.10 V on the low signal circuit is normal.
- If greater than 0.0 V
- Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
- Test for less than 2 Ω in the low signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω.
- Test for less than 1 V between the low signal circuit terminal 3 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- If 0.0 V
- Verify none of the following conditions exist:
- Lean or rich fuel injectors. Refer to Fuel Injector Diagnosis .
- Water intrusion in the HO2S harness connector
- Low or high fuel system pressure. Refer to Fuel System Description .
- Fuel that is contaminated. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- Fuel saturation of the evaporative emission (EVAP) canister
- Exhaust leaks near the HO2S
- Engine vacuum leaks
- If any of the conditions exist
Repair as necessary.
- If none of the conditions exist
- Test or replace the B52 Heated Oxygen Sensor.