Body, generic

B0150 HVAC Mode Door Range/Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

No publicly available J2012 code list includes B0150, and no carmaker publishes it with this meaning. The mode door decides whether air leaves at the face vents, the footwell or the windscreen. A range/performance fault means the door does not reach the commanded position or its feedback does not fit the command. Many actuators carry a potentiometer geared to the motor that returns roughly 0 to 5 V, as a Motor magazine article explains; Calsonic's patent EP0771679A2 pairs each door motor with such a position detector. GM's Global A climate control, as documented for the 2011 Saab 9-5, uses stepper motors and logs mode actuator circuit faults under B0233 instead. Expect air from the wrong outlets or a door that hunts.

Likely causes

Mode door or its linkage binding, broken lever or stripped gear
Mode door actuator worn, feedback track of the potentiometer dirty
End positions not relearned after actuator replacement

Symptoms

  • Air comes out of the wrong vents or the selected mode is not reached
  • Clicking or knocking behind the dashboard while the door moves
  • Windscreen demisting weaker because too little air reaches the defrost outlets

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–600
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

mode door actuatormode door linkagehvac control module

Related codes

B0170B0268B0205

References: motor.com, patents.google.com, saabwisonline.com.