U0074Control Module Communication Bus B Off
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U0074 tells that a module dropped into bus off on Bus B, which the makers that use it assign to an extra powertrain network. GM's 2019 ECM tables call it the Powertrain Expansion CAN, and the LT5 injection module rates its Bus B check Type B, two trips. On 2014-18 trucks and SUVs, PIP5427 ties U0074 to a lost link between ECM and fuel pump module that drives fuel pressure far above target and sets P2635; the communication fault is to be fixed first. FCA's label for the code refers to its Dedicated Powertrain CAN (D-PT): a PCM reflash cures it on the 2019 Ram 1500 eTorque, and on 2022-24 Wranglers it comes with a binding shifter. Ford lists it on 2017-18 F-150s with a badly secured transmission harness, and its diesel PCMs set it when a line stays shorted or open longer than 10 ms.
- What you may notice
- Service Engine Soon lamp or MIL on
- Fuel pressure well above the requested value (GM trucks)
- Shifter binds or shift concerns
- No crank or start-stop inoperative
- Likely causes
- LikelyDamaged or poorly routed powertrain harness on Bus B
- PossibleEngine module software fault, fixed by reprogramming
- PossibleLoose connector, bent pin or badly seated fuse on a Bus B module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · 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.