U0338 code meaning
Software Incompatibility With Remote Function Actuation Module
What U0338 means
The remote function actuation module receives key fob, passive entry and, on newer cars, phone key signals and passes lock, unlock or start requests to the body controller. U0338 means a partner rejects its software. No manufacturer documents U0338 publicly. Jaguar Land Rover shows the typical trap: RFA service parts FK72-19H440 for several Jaguar models from model year 2015 came loaded with software intended for dual-CAN cars, so in these multi-CAN cars the new module stayed silent towards the tester until its fuse was pulled and refitted and the module configured (SSM72557). For Land Rover models from 2010, JLR traces failed RFA downloads to low battery voltage, an interrupted diagnostic link or a corrupted file (SSM71856). U0214 is lost contact, U0515 invalid data. Keyless entry or start may fail.
U0338 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0338
- Remote or keyless locking does not respond
- Keyless start refused or key not detected
- Module not reachable by the diagnostic tool after replacement
Common causes of U0338
- Most likelyReplacement module shipped with software for another network layout
- PossibleSoftware download aborted by low voltage, a lost link or a corrupted file
- PossibleModule fitted but not configured or keys not programmed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Remote function module
What each part of U0338 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 38 | The exact fault in that area. |
What to do next
- Note U0338 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 U0338
What does U0338 mean?
U0338 means "Software Incompatibility With Remote Function Actuation Module". The remote function actuation module receives key fob, passive entry and, on newer cars, phone key signals and passes lock, unlock or start requests to the body controller. It is a generic code, so it means the same on every make.
Is it safe to drive with U0338?
U0338 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0338 fail an emissions test?
U0338 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 U0338 to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will U0338 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.