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: B+ circuit terminal 2/B & Output terminal @ F28UA 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. Test for infinite resistance between the test points: B+ circuit terminal 2/B & Ground
   • If less than infinite resistance, repair the short to ground on the circuit.
   • If infinite resistance, replace the component: M47 Reverse Inhibit Solenoid Actuator

• If the test lamp turns On 

Verify the test lamp turns On and Off.

• If the test lamp is always Off 

1. Ignition/Vehicle Off & Remove Test lamp
2. Disconnect the 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 1/A @ Component harness & Ground
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V
5. Ignition/Vehicle Off
6. Test for less than 2 Ω between the test points: Control circuit terminal 1/A @ Component harness & the other end of the circuit
   • 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

• If the test lamp is always On 

1. Ignition/Vehicle Off & Remove Test lamp
2. Disconnect the electrical connector: K20 Engine Control Module
3. 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.
   • If infinite resistance, replace the component: K20 Engine Control Module

• If the test lamp turns On and Off