U0599
Invalid Data Received From DC/DC Converter Control Module A
A receiving module detected implausible data from DC/DC converter module A. Output current or voltage values fail plausibility checks and are rejected; 12-V system may face load shedding.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Common causes
Ordered by how often each turns out to be the cause.
- Module internal fault or sensor input driftCommon
- Software version mismatch after replacementPossible
- Gateway module routing CAN messages incorrectlyLess likely
Parts involved
- Dc Dc Converter Module A
U0599 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.