Circuit/System Testing

Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B203 Engine Coolant Radiator Temperature Sensor. It may take up to 2 minutes for all vehicle systems to power down.
Test for less than 5 Ω between the low reference terminal 2 and ground.
- If 5 Ω or greater
1. Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for less than 2 Ω in the low reference 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.
- Go to next step: If less than 5 Ω
Vehicle in Service Mode.
Verify the scan tool Radiator Coolant Temperature Sensor parameter is colder than -39°C (-38°F).
- If warmer than -39°C (-38°F)
1. Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the signal circuit terminal 1 and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance, replace the K20 Engine Control Module.
- Go to next step: If colder than -39°C (-38°F)
Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2, Vehicle in Service Mode.
Verify the scan tool Radiator Coolant Temperature Sensor parameter is warmer than 140°C (284°F).
- If colder than the 140°C (284°F)
1. Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module, Vehicle in Service Mode.
2. Test for less than 1 V between the signal circuit and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - Go to next step: If less than 1 V
3. Vehicle OFF
4. Test for less than 2 Ω in the 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.
- Go to next step: If warmer than 140°C (284°F)
Test or replace the B203 Engine Coolant Radiator Temperature Sensor.