Circuit/System Testing

DTC B023A

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the components listed below. It may take up to 2 min for all vehicle systems to power down.
   • M37 Mode Door Actuator
   • M46 Air Recirculation Door Actuator
   • M6L Air Temperature Door Actuator - Left
   • M6R Air Temperature Door Actuator - Right
2. Disconnect the X3 and X4 harness connectors at the K33 HVAC Control Module.
3. Test for infinite resistance between the K33 HVAC Control Module 12 V reference circuit terminal 15 X3 and ground.
   • If less than infinite resistance 

     Repair the short to ground on the circuit.

   • Go to next step: If infinite resistance 
4. Ignition ON.
5. Test for less than 1 V between the K33 HVAC Control Module 12 V reference circuit terminal 15 X3 and ground.
   • If 1 V or greater 

     Repair the short to voltage on the circuit.

   • Go to next step: If less than 1 V 
6. Connect the X3 and X4 harness connectors at the K33 HVAC Control Module, ignition ON.
7. Clear all DTCs.
8. Verify DTC B023A is not set.
   • If the DTC is set. 

     Replace the K33 HVAC Control Module.

   • Go to next step: If the DTC is not set. 
9. Verify DTC B023A does not set after connecting each of the components listed below one at a time and operating them through their full range.
   • M37 Mode Door Actuator
   • M46 Air Recirculation Door Actuator
   • M6L Air Temperature Door Actuator - Left
   • M6R Air Temperature Door Actuator - Right
   • If the DTC sets 

     Replace the component that was connected immediately before the DTC set.

   • Go to next step: If the DTC does not set 
10. All OK.

DTC B0223, B022A, B0233, B0408 or B0418

1. Ignition OFF, disconnect the harness connector at the appropriate door actuator, ignition ON.
NOTE:

If more than one actuator is affected, test the B+ circuit at each actuator.

2. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground.
   • If the test lamp does not illuminate 
   1. Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module.
   2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: 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 K33 HVAC control module.
   • Go to next step: If the test lamp illuminates 
3. Ignition ON, command the appropriate actuator with a scan tool.
4. Verify a test lamp is flashing on and off when connected between the B+ circuit terminal 2 and each control circuit terminal listed below:
   • Control Circuit - terminal 1
   • Control Circuit - terminal 3
   • Control Circuit - terminal 4
   • Control Circuit - terminal 6
   • If the test lamp is always OFF 
   1. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module. Vehicle in Service Mode.
   2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
   3. Vehicle OFF.
   4. 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 K33 HVAC Control Module.
   • If the test lamp is always ON 
   1. Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
   2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K33 HVAC Control Module.
   • Go to next step: If the test lamp is flashing On and Off 
5. Test or replace the actuator.