Circuit/System Testing
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition/Vehicle - Off
- Disconnect the appropriate electrical connector : E12 Glow Plug
- Ignition - On / Vehicle - In Service Mode
- Connect a test lamp between the test points: Control circuit terminal 1/A & Ground
- Perform the scan tool control function: Glow Plugs - On and Off
Verify the test lamp turns On and Off.
- If the test lamp is always Off
- Ignition/Vehicle - Off & Remove - Test lamp
- Disconnect the electrical connector : X2 @ K20 Engine Control Module
- Test for infinite resistance between the test points: Control circuit terminal 1/A @ Component harness & Ground
- If less than infinite resistance - Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 ohms between the test points: Control circuit terminal 1/A @ Component harness & The other end of the circuit @ Control module harness
- If 2 ohms or greater - Repair the open/high resistance in the circuit.
- If less than 2 ohms - Replace the component: K20 Engine Control Module
- If the test lamp is always On
- Ignition/Vehicle - Off & Remove - Test lamp
- Disconnect the electrical connector : X2 @ K20 Engine Control Module
- Ignition - On / Vehicle - In Service Mode
- Test for less than 1 V between the test points: Control circuit terminal 1/A @ Component harness & Ground
- If 1 V or greater - Repair the short to voltage on the circuit.
- If less than 1 V - Replace the component: K20 Engine Control Module
- Go to next step: If the test lamp turns On and Off
- Test or replace the component: E12 Glow Plug