Circuit/System Testing

• If the test lamp does not turn On and the circuit fuse is OK 

1. Ignition/Vehicle - Off & Remove - Test lamp
2. Test for less than 2 Ω between the test points: Ignition circuit terminal 1 & Output terminal @ Fuse
   • If 2 Ω or greater - Repair the open/high resistance in the circuit.
   • If less than 2 Ω - Verify the fuse is OK and there is voltage at the fuse.

• If the test lamp does not turn On and the circuit fuse is open 

1. Ignition/Vehicle - Off & Remove - Test lamp
2. Replace the component: Fuse
3. Ignition - On / Vehicle - In Service Mode
4. Verify the fuse does not open.
   • If the fuse opens and there are components connected to the circuit - Disconnect a component and repeat procedure starting at step 4.1
   • If the fuse opens with all components disconnected from the circuit - Repair the short to ground on the circuit.
   • If the fuse does not open after disconnecting a component from the circuit - Replace the component disconnected last.
   • Go to next step: If the fuse does not open
NOTE:

It may be necessary to use a scan tool control function to operate a component.

5. Operate the component: Each component on the circuit - One at a time

   Verify the fuse does not open when any of the components are activated.

   • If the fuse opens - Replace the component that caused the fuse to open when activated.
   • Go to next step: If the fuse does not open
6. All OK.

• Go to next step: If the test lamp turns On 

• If the test lamp turns On 

1. Ignition/Vehicle - Off & Remove - Test lamp
2. Disconnect the appropriate electrical connector: K20 Engine Control Module
3. Test for infinite resistance between the test points: Control circuit terminal 2 @ Component harness & Ground
   • If less than infinite resistance - Repair the short to ground on the circuit.
   • If infinite resistance - Replace the component: K20 Engine Control Module

• Go to next step: If the test lamp does not turn On 

Verify a test lamp turns On between the test points: Control circuit terminal 2 & Ignition circuit terminal 1

• If the test lamp does not turn On 

1. Ignition/Vehicle - Off & Remove - Test lamp
2. Disconnect the appropriate electrical connector: K20 Engine Control Module
3. Ignition - On / Vehicle - In Service Mode
4. Test for less than 1 V between the test points: Control circuit terminal 2 @ Component harness & Ground
   • If 1 V or greater - Repair the short to voltage on the circuit.
   • Go to next step: If less than 1 V
5. Ignition/Vehicle & All vehicle systems - Off
6. Test for less than 2 Ω between the test points: Control circuit terminal 2 @ Component harness & The other end of the circuit @ Control module harness
   • If 2 Ω or greater - Repair the open/high resistance in the circuit.
   • If less than 2 Ω - Replace the component: K20 Engine Control Module

• Go to next step: If the test lamp turns On