What this code means
B1233 can indicate an open in the driver's air mix control motor circuit.
B1233 concerns an open in the driver's air mix control motor circuit. The climate control unit stores the code when the motor's input voltage is above the specified value. The inspection path separates the motor-related connector result, the connecting wires and the climate control unit's internal circuit voltage.
Two voltage checks in this procedure have the same approximate expected value, but they are taken at different places and with different connector arrangements. Understanding those setups is more useful than treating every mention of that voltage as the same test.
What the vehicle may do
- The motor's input voltage may be above the specified value.
- The climate control unit can store B1233 for that condition.
Possible fault areas
- The air mix control motor may have a problem.
- The related wiring may have an open circuit.
- The climate control unit may have a problem.
The first voltage check is at the disconnected air mix motor connector, with IG Mode ON. The wire inspections then use disconnected connectors and their stated resistance criterion. The later climate-control-unit check examines internal circuit voltage under its own specified connection condition.
This sequence separates the output observed at the motor connector from the paths linking it to the unit and the voltage measured at the control unit itself. The normal and abnormal interpretations belong to those individual setups.
Diagnostic path
Understand the stored condition
B1233 identifies an open in the Driver's Air Mix Control Motor circuit. We will call it the air mix motor from here. The climate control unit stores this code when the motor's input voltage is above the specified value. Possible fault areas include the motor, its wiring, and the climate control unit.
Before troubleshooting
The HDS function path is Body Electrical, then HVAC, then Data List.
Starting condition
To confirm the code, turn the vehicle to the ON mode.
Check voltage at the motor connector
This check evaluates the component through its related components. These checks test the related components instead. Disconnect the air mix control motor connector (5P). With IG Mode ON, check the unit output voltage at that disconnected connector.
- First probe: female terminal 3 and the other on female terminal 4.
A normal reading is about 5 volts. If the reading is normal, there is a problem with the air mix motor. If the reading is abnormal, there is a problem with other related components.
At the motor-side voltage check, the measurement is between female terminals 3 and 4 of the disconnected 5P connector, with IG Mode ON. About 5 volts is the normal result for that setup. The later control-unit voltage check uses female terminals 16 and 19 of connector B (24P), also with the stated approximate voltage criterion.
The intervening wire checks explain the connection between these locations: motor terminal 4 pairs with unit terminal 16, and motor terminal 3 pairs with unit terminal 19. Their normal criterion is less than 1 ohm under the stated disconnected-connector conditions. The matching endpoints show how the voltage and wire inspections relate, while preserving their different setups and conclusions.
Check the first wire path
For the AMD-P-DR, SENS-COM Open Wire Inspection, disconnect the air mix control motor connector (5P) and climate control unit connector B (24P). Use IG Mode OFF for this resistance check, and keep both connectors disconnected.
- First probe: air mix control motor connector (5P) female terminal 4.
Place the other on climate control unit connector B (24P) female terminal 16. Check the resistance. A normal reading is less than 1 ohm. An abnormal result means there is a problem in the circuit.
Check the second wire path
Keep IG Mode OFF. Keep the air mix control motor connector (5P) and climate control unit connector B (24P) disconnected.
- First probe: air mix control motor connector (5P) female terminal 3.
Place the other on climate control unit connector B (24P) female terminal 19. Check the resistance. A normal reading is less than 1 ohm. An abnormal result means there is a problem in the circuit.
Check the climate control unit
For the Climate Control Unit Inspection, disconnect the air mix control motor connector (5P). Keep climate control unit connector B (24P) connected for this check. With IG Mode ON, check the unit's internal circuit voltage.
- First probe: connector B (24P) female terminal 16 and the other on female terminal 19.
A normal reading is about 5 volts. If the reading is abnormal, there is a problem with the climate control unit.
Takeaway
B1233 may involve the air mix motor, its wiring, or the climate control unit. These readings help you identify which area has a problem.
Final check
B1233 may involve the air mix motor, its wiring, or the climate control unit.
The diagnosis connects the motor-circuit voltage result, the separate wire-path results and the climate-control-unit result. Use each conclusion only with the condition that produced it. This keeps the final fault area grounded in the measured path or operating check.
