B0502 code meaning
Left Rear Power Window Circuit Malfunction
What B0502 means
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.
B0502 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of B0502
- 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
Common causes of B0502
- Most likelyHall sensor in the motor or its supply faulty
- PossibleLeft rear window motor worn or with an open winding
- PossibleWires broken in the rear door hinge passage
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Left rear window motorRear door moduleBody control module
What each part of B0502 means
| B | Body system: airbags, seat belts, power seats, lights and climate control. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 02 | The exact fault in that area. |
What to do next
- Note B0502 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about B0502
What does B0502 mean?
B0502 means "Left Rear Power Window Circuit Malfunction". B0502 has no entry in any accessible J2012 list, and no carmaker describes it, so the code stays unproven. It is a generic code, so it means the same on every make.
Is it safe to drive with B0502?
B0502 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B0502 fail an emissions test?
B0502 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is B0502 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will B0502 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.