U0502 code meaning
Invalid Data Received From Door Control Module C
What U0502 means
For door control module C the letter is a weak guide. In the generic list its lost-communication partner is U0201, yet GM's 2011 Saab 9-5 code list uses U0201 for the transfer case control module. So on some makes the slot is not a door at all, and the vehicle's own fault text decides. Where it does mean a third door unit, the check is the usual one: frames from C arrive, but their content is rejected because a signal is undefined, the alive counter does not step correctly or the checksum fails. Saab sorts such findings into subtypes 71, 72 and 74 after the code. No public bulletin names U0502. Door-related effects, if any, are confined to the door C controls; total loss of contact is U0201.
U0502 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0502
- Lock, window or mirror of one door working only sometimes
- Stored code without noticeable fault
Common causes of U0502
- PossibleDoor control module C internally faulty
- PossibleDamaged wiring in the door hinge area
- Less likelyManufacturer uses this code slot for another module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Door control module c
What each part of U0502 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 02 | The exact fault in that area. |
What to do next
- Note U0502 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 U0502
What does U0502 mean?
U0502 means "Invalid Data Received From Door Control Module C". For door control module C the letter is a weak guide. It is a generic code, so it means the same on every make.
Is it safe to drive with U0502?
U0502 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0502 fail an emissions test?
U0502 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 U0502 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U0502 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.