OBD-II trouble code
U0310: Software Incompatibility With Fuel Pump Control Module
The fuel pump control module is running a calibration that does not belong with the rest of the vehicle's software. Of all the software-incompatibility codes, this is the one most likely to leave you at the roadside, because the mismatched data is a pressure map rather than a comfort setting.
Quick facts
- System
- Network
- Category
- Network Communication
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $600
- DIY difficulty
- Shop recommended
What does U0310 mean?
This code applies to vehicles that use a dedicated fuel pump control module — often called a fuel pump driver module — rather than running the pump at a fixed voltage through a relay. On those systems the module varies pump speed continuously to hold a target rail pressure, and it does so from a calibration table that has to match the engine controller's expectations. This code stores when the network concludes that the fuel pump module's software version does not belong to the coordinated set the rest of the vehicle is running.
What separates this code from its siblings is what the mismatched software actually contains. In most members of this family the calibration is behaviour: how a module responds to a request, what messages it sends. Here the calibration is a set of numbers describing pressure targets and duty cycles across the whole operating range. Two consequences follow from that.
The first is that the failure is a driveability failure, not just a lamp. Wrong pressure targets produce hard starting, a long crank, stalling as load changes, hesitation on acceleration, or no start at all. This is one of the few software-incompatibility codes that genuinely strands people, so it should not be filed alongside a mismatched infotainment module.
The second is quieter and more expensive. A calibration mismatch does not always cause a dramatic symptom. It can equally result in the pump being commanded to run harder than it needs to across the whole range — the engine runs fine, the regulator bleeds off the excess, and nothing seems wrong. But a pump held at high duty all the time runs hotter, wears faster, and returns warmed fuel to the tank. A vehicle that has driven for months on a mismatched fuel pump calibration can arrive with a healthy-looking fault list and a pump nearing the end of its life. If the mismatch has been present a long time, mention that to the owner rather than promising the reflash restores everything.
The causes are almost always service history rather than component failure. The module was replaced without being programmed to this vehicle's VIN. A second-hand unit was fitted and never reprogrammed — a particularly common route here, because on most designs this module is mounted low and toward the rear of the vehicle, under the rear seat, in the boot floor, or on the fuel tank itself, which makes it a routine casualty of flooding and rear-end damage and therefore something people replace from a breaker. An update was applied to the engine controller and not to this module. A reflash was interrupted, or performed with a file for a different variant. Aftermarket engine tuning is another real cause on turbocharged and direct-injection vehicles, where a remap raises fuel demand and the pump module is left on stock data.
Because the root cause is data, no amount of electrical testing will find it. The fix is to bring the module's software back into a matching, manufacturer-approved set with a proper tool and a stable supply.
Common causes
- Fuel pump control module replaced without VIN-specific programming
- Second-hand module fitted from another vehicle and never reprogrammed — common because this module's low, rear mounting makes it a frequent flood and collision casualty
- Engine controller updated while the fuel pump module was left on its previous calibration
- Reflash interrupted by a voltage drop partway through programming
- Programming performed with a file for a different engine or market variant
- Aftermarket engine remap raising fuel demand beyond what the stock pump calibration supports
- Hardware and software part numbers left mismatched after a fuel system repair
- Module replaced as part of a fuel pump assembly change without the programming step being completed
Symptoms
- Warning light with this code stored, often beside other network software codes
- Long crank or hard starting, particularly when the engine is hot
- Stalling as load changes, or hesitation under acceleration
- No start where rail pressure control is disrupted entirely
- Reduced power or a limited-performance condition
- Fuel pump audibly running harder or more constantly than it used to
- Fault present since a fuel pump, fuel tank or module replacement
- Fault present since an aftermarket engine remap
Diagnostic steps
- 1.Establish the service history first. This code follows a module replacement, an update, a reflash or a remap in the great majority of cases, so ask what has been done and when.
- 2.Read the fuel pump control module's software and calibration part numbers and compare them against the manufacturer's current approved set for the VIN.
- 3.Ask specifically whether a second-hand module was fitted. Its low rear mounting makes it a common flood and collision replacement, and used units carry another vehicle's data.
- 4.Note any companion network codes, which help confirm that the fuel pump module rather than another controller is the mismatched one.
- 5.Check whether the engine has been remapped. A tune that raises fuel demand without matching pump module data produces this code on an otherwise healthy vehicle.
- 6.Before reprogramming, confirm battery voltage is stable and connect a proper programming supply, since an interrupted flash is itself one of the causes on this list.
- 7.Reprogram the fuel pump control module — and any related modules — to the matching approved calibration using a manufacturer-approved tool.
- 8.Verify live rail pressure against target through idle, a load transition and a hot restart after programming, rather than only confirming the code has gone.
- 9.If the mismatch has been present for a long period, assess pump condition as well, because a pump held at high duty for months wears faster than one running to its proper map.
- 10.Clear codes and confirm the fault does not return after a full key cycle and a road test.
Repair cost
$100 – $600
This is a programming repair rather than a parts repair. Reprogramming the fuel pump control module to the correct calibration is typically $100 to $300, rising to $300 to $600 where the calibration is dealer-only or several modules have to be brought into line together. If a used module was fitted, the earlier repair is the real expense and this code is only the symptom. Where the mismatch has run for months and the pump has been driven at high duty throughout, budget separately for a fuel pump at $500 to $1,200 — the reflash corrects the data but does not undo the wear.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with pcm replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.