B2492

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DTC B2492, B2493, B2494
Air-blending flap stepping motor, shorting to ground, open circuit, shorting between terminals.

Conditions
B2492: Shorting to ground.
B2493: Generated only during calibration. Start fault diagnosis by reading the trouble codes, if any, and making a note of them. Then carry out calibration and read the trouble codes again.
B2494: Shorting between terminals.

Diagnostic Procedure
1. Connect a BOB to the ACC control module's wiring (the control module should not be connected).
Check the resistance of the windings in the two stepping motors by taking a reading across terminals 8 and 27 and terminals 28 and 29. The correct resistance is about 100 ohms in both cases.
Also check that no shorting to ground occurs by measuring the resistance across ground and terminals 8, 27, 28 and 29. The correct resistance is OL (infinite).
Proceed directly to point 4 if all readings are OK.
2. If the resistance of the windings is not OK, repeat the resistance measurement on connector H10-5 as follows:
- Across pins 1 and 2.
- Across pins 3 and 4.
In both cases the resistance should be about 100 ohms.
If it is not, change the stepping motor.
3. Check the wiring between the ACC control module and connector H10-5 for shorting to ground or shorting between the terminals and or open circuit. Locate the short circuit and rectify it.
4. Clear the trouble codes, if any. Calibrate the ACC system. Check whether the trouble codes are generated afresh. If they are; proceed to "Before Changing A Control Module" for further diagnostic procedures. Testing and Inspection