B2403

Air distributor stepping motor, open/short circuit to ground.

Conditions
B2402: Short circuit to ground.
B2403: Open circuit, registered only when calibrating. Start fault diagnosis by reading any diagnostic trouble codes and noting them down.
Calibrate and read the diagnostic trouble codes again.

Action
1 Connect a breakout box (BOB) to the Automatic Climate Control (ACC) control module wiring harness. The control module should not be connected.
Check winding resistance in both the stepping motor windings by measuring between connections 23 and 24 and between connections 25 and 26. Correct reading should be approx. 100 Ohm in both cases.
Also check that there is no short circuit to ground by measuring the resistance between ground connections 23, 24, 25 and 26. The correct value should be infinite (OL).
If all values are correct, proceed to point 4.
2 If the winding resistance is incorrect, repeat the measurement in connector H10-4 as follows:
- Measure between pins 5 and 6.
- Measure between pins 7 and 8.
In both cases, the value should be about 100 ohms. If any of the values is incorrect, change the stepping motor.
3 Check the wiring harness between connector H10-4 and the ACC control module for short circuits to ground or short circuits between the connectors and/or open circuits.
Localize and remedy the short circuit.
4 Erase any diagnostic trouble codes.
Calibrate the ACC system.
If the diagnostic trouble code is reregistered.
Proceed to "Action Before Changing A Control Module". Before Changing a Control Module