U055C
Invalid Data Received From Special Purpose Vehicle Control Module C
A receiving module detected implausible data from special-purpose vehicle (SPV) control module C. Upfit function (emergency lighting, sirens, fleet relays, PTO/auxiliary) status values fail plausibility checks and are rejected.
- Check engine light: Not always
- Emissions related: No
- Repair difficulty: medium
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
- Special Purpose Vehicle Module C
U055C 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.