Body, generic

B0502 Left Rear Power Window Circuit Malfunction

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0502 has no entry in any accessible J2012 list, and no carmaker describes it, so the code stays unproven. Its title concerns the left rear window circuit. In the Saab 9-3 the left rear door module logs B3210 04 when the motor's up path is open and the glass will not close, and B3543 if the two Hall signals arrive in reverse order for 150 ms, which disables one-touch travel. GM's 2011 9-5 assigns the left rear motor B3215. Microchip's AVR480 note shows why the Hall pulses matter: speed, current and glass position feed the pinch check. FMVSS 118 demands reversal before 100 N for any window that closes on its own. Many rear doors carry a child lockout; a locked-out rear switch is intended and not a fault.

Likely causes

Hall sensor in the motor or its supply faulty
Left rear window motor worn or with an open winding
Wires broken in the rear door hinge passage

Symptoms

  • Left rear window will not close or will not open
  • One-touch function and pinch protection not available
  • Window reverses on its own without an obstacle

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–450
Time0.5–3 h

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

Parts involved

left rear window motorrear door modulebody control module

Related codes

B0503B0500U0224

References: saabwisonline.com, saabwisonline.com, saabwisonline.com, ww1.microchip.com.