Circuit/System Testing

Verify that no other DTCs are set except for DTC P156D.
- If any other DTCs are set
  Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Go to next step: If only DTC P156D is set
Replace the T19 Power Supply Transformer.
Verify the DTC does not set while operating the vehicle within the Conditions for Running the DTC.
- If DTC sets
  Replace the K20 Engine Control Module.
- Go to next step: If DTC does not set
All OK.