U033CSoftware Incompatibility With Hybrid/EV Battery Interface Control Module C
- Generic OBD-II code · Network
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U033C names the third interface board. GM's closest published check is its own code P1EB1 in the VITM of the Volt: at power-up the controller compares its own software version with that of all slave boards and logs P1EB1 if any one does not fit, within 200 ms, with at least 9 V and no slave lost-communication fault active. The 2015 table enters it as one trip, the 2018 table as Type A, meaning a MIL after one failed drive. GM thus reports one summary code rather than one per board, and a letter code like U033C does not appear there. Where a maker does use the letter codes, C stands for the third board only; U01A2 covers lost contact with it, U04A3 invalid data.
- What you may notice
- MIL possible on hybrids, as GM rates its comparable check Type A
- Hybrid or high-voltage battery warning after switching on
- Electric driving or charging restricted
- Likely causes
- LikelyBoard C carries a software version the battery controller does not list as compatible
- PossibleBattery controller updated while the boards stayed on the old level
- RareUnstable low-voltage supply at power-up corrupts the version exchange
- Inspection (ITP)
- Can matter for the ITP: it concerns the emissions system.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €60 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.