B2492

Air mixing damper stepping motor, open/short circuit to ground.

Conditions
B2492: Short circuit to ground.
B2493: 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 BOB to the Automatic Climate Control (ACC) control module's wiring harness. Control module should not be connected.
Check the winding resistance in both the stepping motor windings by measuring between connections 27 and 28 as well as between connections 29 and 30.
In both cases, the correct value should be about 100 ohms.
Also check that there is no short circuit to ground by measuring the resistance between pin 1 and pins 27, 28, 29 and 30.
The correct value should be infinite (OL).
If all values are correct, proceed directly to point 4.
2 It the winding resistance is incorrect, repeat the measurement in connector H10-4 as follows:
- Measure between pins 1 and 2.
- Measure between pins 3 and 4.
In both cases, readings should be approx. 100 Ohm.
If any of the values are 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.
Check to see if the diagnostic trouble code returns.
Proceed to "Action Before Changing A Control Module". Before Changing a Control Module