U010BLost Communication With Exhaust Gas Recirculation Control Module B
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U010B names the second exhaust gas recirculation control module, B. Its existence implies an engine with two separately controlled EGR units, for example a high- and a low-pressure loop on a diesel or one unit per cylinder bank; which one is B is the maker's choice. The code itself only says that a node expecting periodic messages from module B no longer receives them. Neither a manufacturer document nor any entry in the NHTSA bulletin index names U010B. Diagnosis therefore follows the generic path: supply, ground and bus lines of module B first, then the module. If only B is silent while A (U010A) still talks, the fault sits in B's branch. Invalid data from B is U040C; CARB's EGR monitoring makes the code emission-relevant.
- What you may notice
- MIL on
- Second EGR path inactive, possible NOx increase
- Module B not reachable with a scan tool
- Likely causes
- LikelyEGR module B without power or ground
- PossibleOpen or chafed bus branch to module B
- PossibleLoose or heat-damaged connector at module B
- RareEGR module B internally faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.