U0109 code meaning
Lost Communication With Fuel Pump Control Module A
Network system Generic code U01xx codes Check engine light
What U0109 means
U0109 means the engine controller no longer hears fuel pump control module A, the electronics that drive the in-tank pump at variable speed. GM's 2019 Corvette LT5 table watches frames $1EB and $4D9 and sets the code after 10 s as Type B over two trips. Ford instead returns the module status on a duty-cycle line: its 2020–2023 gasoline summary flags feedback stuck at 0 % or 100 %, the 2023 diesel summary a pump duty below 5 % or above 95 % for 0.5 s. Ford TSB 16-0060 (Super Duty 6.2/6.8 L, MIL) replaces the module; GM PIC5655A (Volt 2011–2013) points to a loose feed on circuit 1540 or its fuse in the rear fuse block. Pump B has U016C. Expect hard starts, stalling or no start.
U0109 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0109
- MIL on
- Long cranking, stalling or no start
- Hesitation under load from low fuel pressure
Common causes of U0109
- Most likelyLoose fuse, relay or feed terminal supplying the pump module
- PossibleFuel pump module internally faulty (common on some trucks, replaced by bulletin)
- PossibleCorroded connector or damaged wiring near the tank or frame
- Less likelyEngine controller software setting the code falsely
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel pump control moduleCAN bus wiring
What each part of U0109 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 09 | The exact fault in that area. |
What to do next
- Note U0109 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 U0109
What does U0109 mean?
U0109 means "Lost Communication With Fuel Pump Control Module A". U0109 means the engine controller no longer hears fuel pump control module A, the electronics that drive the in-tank pump at variable speed. It is a generic code, so it means the same on every make.
Is it safe to drive with U0109?
Drive gently and only to a workshop. With U0109 the car can go into limp mode (reduced power) to protect itself.
Will U0109 fail an emissions test?
Yes, it can. U0109 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 U0109 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U0109 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.