LEMON Manuals: Even more car manuals for everyone
Home >> Buick >> 2019 >> LaCrosse Base >> Repair and Diagnosis >> Hybrid/Electric Powertrain >> Cooling Systems >> Hybrid/EV Cooling >> Diagnostic Information and Procedures >> DTC P0CEF-P0CF2 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition/Vehicle - Off - Disconnect the harness connector at the B235 Starter/Generator Coolant Temperature Sensor
  2. Test for less than 5 ohms between the test points: Low Reference circuit terminal 2 & Ground
    • If 5 ohms or greater 
    1. Ignition/Vehicle - Off - Disconnect the X1 harness connector at the K59 Starter/Generator Control Module
    2. Test for less than 2 Ω in the low reference circuit end to end.
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K59 Starter/Generator Control Module
    • Go to next step: If less than 5 ohms 
  3. Ignition/Vehicle - On
  4. Verify the scan tool parameter: Drive Motor Coolant Temperature sensor parameter is colder than -39°C (-38°F).
    • If warmer than -39°C (-38°F) 
    1. Ignition/Vehicle - Off - Disconnect the X1 harness connector at the K59 Starter/Generator Control Module
    2. Test for infinite resistance between the test points: Signal circuit & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K59 Starter/Generator Control Module
    • Go to next step: If colder than -39°C (-38°F) 
    5. CAUTION:

    If the fuse in the jumper wire opens, the signal circuit may have a short to a voltage or a short to ground and the sensor might be damaged.

  5. Connect a 1 A fused jumper wire between the test points: Signal circuit terminal & Ground
  6. Verify the scan tool parameter: Drive Motor Coolant Temperature sensor parameter is warmer than 149°C (300°F).
    • If 149°C (300°F) or colder 
    1. Ignition/Vehicle - Off - Remove the jumper wire, disconnect the X1 harness connector at the K59 Starter/Generator Control Module
    2. Ignition/Vehicle - On - Test for less than 1 V between the test points: Signal circuit terminal & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Ignition/Vehicle - Off
    4. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K59 Starter/Generator Control Module
    • Go to next step: If warmer than 149°C (300°F) 
  7. Replace the component: B235 Starter/Generator Coolant Temperature Sensor
scientia non olet · About LEMON Manuals