Body, generic

B0252 Driver Window Motor Down Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

For B0252 there is neither a J2012 entry nor any factory description, so the code is unverified. The title names one direction of the driver's window motor. A reversible DC motor moves the glass; the down path is the half of the drive that puts supply on one motor terminal and ground on the other. In patent US6906487B2 (International Rectifier, now Infineon) two smart high-side switches and two low-side MOSFETs form that H-bridge, read the motor current and shut down on shorts or overheating. If only the down path fails, the window still closes but will not open, which points to one driver stage, a relay contact or one motor lead. Pinch protection under FMVSS 118 reverses the glass downwards, so a dead down path disables it as well.

Likely causes

Down relay contact or driver transistor in the door module burnt
One motor lead broken in the door or at the motor plug
Worn motor brushes or commutator with a dead spot in one direction

Symptoms

  • Driver's window closes but will not go down
  • Pinch protection or one-touch down no longer works

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–500
Time0.5–2.5 h

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

Parts involved

window motordoor wiring harness

Related codes

B0245B0500

References: patents.google.com, law.cornell.edu, patents.google.com.