Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC : B1246 (B-B3)
DTC B1246 or DTC screen B-B3 : A Problem in the Rear Air Mix Control Motor Circuit, Linkage, Door, or Motor
| DTC Description | DTC |
|---|---|
| B1246 A problem in the rear air mix control motor circuit, linkage, door, or motor |
DTC (AC)
- Problem verification
-1. Clear the DTCs with the HDS.How to Clear DTCs
Clear DTCs
-2. Turn the vehicle to the OFF (LOCK) mode then the ON mode.
-3. Do the Self-Diagnostic Function with the HDS or the climate control unit .
-4. Check for DTCs.
DTC Description DTC B1246 A problem in the rear air mix control motor circuit, linkage, door, or motor Is DTC B1246 or screen B-B3 indicated?
YES
Go to step 2.
NO
Intermittent failure. Check for loose wires or poor connections on the rear air mix control motor circuit.
- Open wire check (M-HOT(RR) line)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connectors.
Climate control unit connector B (36P) Rear air mix control motor 5P connector -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Climate control unit connector B (36P): disconnected Rear air mix control motor 5P connector: disconnected Test circuit M-HOT(RR) Test point 1 Climate control unit connector B (3P) No. 17 (GRY) Test point 2 Rear air mix control motor 5P connector No. 4 (GRY) Is there continuity?
YES
The M-HOT(RR) wire is not open. Go to step 3.
NO
Repair an open in the wire between the climate control unit and the rear air mix control motor.
- Open wire check (M-COOL(RR) line)
-1. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Climate control unit connector B (36P): disconnected Rear air mix control motor 5P connector: disconnected Test circuit M-COOL(RR) Test point 1 Climate control unit connector B (36P) No. 18 (RED) Test point 2 Rear air mix control motor 5P connector No. 5 (RED) Is there continuity?
YES
The M-COOL(RR) wire is not open. Go to step 4.
NO
Repair an open in the wire between the climate control unit and the rear air mix control motor.
- Shorted wire check (M-HOT(RR) line)
-1. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Climate control unit connector B (36P): disconnected Rear air mix control motor 5P connector: disconnected Test circuit M-HOT(RR) Test point 1 Climate control unit connector B (36P) No. 17 (GRY) Test point 2 Body ground Is there continuity?
YES
Repair a short to ground in the wire between the climate control unit and the rear air mix control motor.
NO
The M-HOT(RR) wire is OK. Go to step 5.
- Shorted wire check (M-COOL(RR) line)
-1. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Climate control unit connector B (36P): disconnected Rear air mix control motor 5P connector: disconnected Test circuit M-COOL(RR) Test point 1 Climate control unit connector B (36P) No. 18 (RED) Test point 2 Body ground Is there continuity?
YES
Repair a short to ground in the wire between the climate control unit and the rear air mix control motor.
NO
The M-COOL(RR) wire is OK. Go to step 6.
- Rear air mix control motor check
-1. Test the rear air mix control motor .
Is the rear air mix control motor OK?
YES
Replace the climate control unit .
NO
Replace the rear air mix control motor , or repair the rear air mix control linkage or door.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.