U059A code meaning
Invalid Data Received From DC/DC Converter Control Module B
Network system Generic code U05xx codes Check engine light
What U059A means
Converter B is a second DC/DC unit, used when one voltage support stage is not enough or when separate networks need their own supply. FCA is the only maker that names it publicly: in powertrain module updates for the 2019 Jeep Cherokee with the 3.2-litre V6 and engine stop-start (18-023-19 and follow-ups such as 18-020-21), the PCM lists both U0599 and U059A for invalid data from DC-to-DC converters A and B, plus U0299 for lost contact with converter 2. The customer complaint in those bulletins is a MIL and an engine that sometimes fails to restart after a stop-start event, and the fix is new PCM software rather than a new converter. A failing second converter mostly shows up as start-stop being withdrawn or electronics resetting during restarts.
U059A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.3 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of U059A
- Check engine light
- Engine does not restart after a stop-start event
- Stop-start function withdrawn
Common causes of U059A
- Most likelyPowertrain controller software evaluating converter B data incorrectly (FCA 18-023-19)
- PossibleSecond DC/DC converter faulty
- Less likelyWiring or ground connection of converter B poor
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Dc dc converter module b
What each part of U059A means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 9A | The exact fault in that area. |
What to do next
- Note U059A 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 U059A
What does U059A mean?
U059A means "Invalid Data Received From DC/DC Converter Control Module B". Converter B is a second DC/DC unit, used when one voltage support stage is not enough or when separate networks need their own supply. It is a generic code, so it means the same on every make.
Is it safe to drive with U059A?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U059A fail an emissions test?
Yes, it can. U059A is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U059A to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will U059A clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.