Circuit/System Testing

WARNING: This page is about a different car, the 2016 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.

Control Circuit Low Voltage or Open

Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module. Ignition ON.
Test for B+ voltage between the control circuit terminal 49 and ground.
- If not B+
1. Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block-Underhood.
2. Test for infinite resistance between the control circuit terminal 19 and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance.
3. Test for less than 2 Ω in the control circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the X50A Fuse Block-Underhood.
- If B+
Replace the K20 Engine Control Module.

Control Circuit High Voltage

Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block-Underhood. Ignition ON.
Test for less than 1 V between terminal 19 and ground
- If greater than 1 V
1. Disconnect the X1 harness connector at the K20 Engine Control Module.
2. Test for less than 1 V between the control circuit terminal 49 and ground.
  - If greater than 1 V, repair the short to voltage on the circuit.
  - If infinite resistance.
3. Test for less than 2 Ω in the control circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If 1 V or less, replace the K20 Engine Control Module.
- If 1 V or Less
Replace the X50A Fuse Block-Underhood.