U0074 code meaning
Control Module Communication Bus B Off
Network system Generic code U00xx codes Check engine light
What U0074 means
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.
U0074 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0074
- 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
Common causes of U0074
- Most 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
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
CAN bus wiringCAN terminating resistorControl module
What each part of U0074 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 74 | The exact fault in that area. |
What to do next
- Note U0074 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0074
What does U0074 mean?
U0074 means "Control Module Communication Bus B Off". U0074 tells that a module dropped into bus off on Bus B, which the makers that use it assign to an extra powertrain network. It is a generic code, so it means the same on every make.
Is it safe to drive with U0074?
Drive gently and only to a workshop. With U0074 the car can go into limp mode (reduced power) to protect itself.
Will U0074 fail an emissions test?
Yes, it can. U0074 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U0074 to fix?
Difficulty: hard. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will U0074 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.