Circuit/System Testing

WARNING: This page is about a different car, the 2018 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
Connect a 3 A fused jumper wire between the control circuit terminal 67 and ground, ignition ON.
Verify a test lamp illuminates between the ignition circuit terminal 51 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF, remove the test lamp.
2. Test for less than 2 Ω in the ignition circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
  NOTE:
  The ignition circuit may supply voltage to other components. Make sure to test all circuits and components for a short to ground that share the ignition circuit.
1. Ignition OFF, remove the test lamp, and disconnect all components on the circuit.
2. Test for infinite resistance between the ignition circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
3. Replace the fuse, ignition ON.
4. Verify the fuse is good after connecting each of the components one at a time.
  - If the fuse opens, replace the component that opens the fuse when connected.
  - If the fuse is good, all OK.
- Go to next step: If the test lamp illuminates
Replace the K20 Engine Control Module.