Failed fuel rack position sensor, rated the likely cause (OBD-Codes.com). Fuel injection pump actuator (fuel quantity actuator) failure (both sources). Open, short to voltage or short to ground in the sensor signal circuit, or lost power or ground at the sensor (OBD-Codes.com). Wiring issue (RepairPal). Fuel injection pump failure (RepairPal). Failed PCM, rated unlikely by OBD-Codes.com (both sources).

Clean or repair corroded or damaged connectors at the pump sensor. Repair open or shorted signal, power or ground wiring. Replace the fuel rack position sensor / fuel quantity actuator if circuits test good. Replace the fuel injection pump if it is at fault (RepairPal lists fuel pump replacement as the common repair). Replace and program the PCM only after the other parts are ruled out.

P0252🔧 Diesel fuel injection pump meteringDrive with caution, fix soon

P0252: Injection Pump Fuel Metering Control A Range/Performance (Meaning, Causes, Fixes)

Q: What does P0252 mean?

P0252 is a diesel code that means the engine computer saw a fuel metering control signal from the injection pump that is out of its expected range. OBD-Codes.com says a failed fuel rack position sensor is the likely cause, with wiring faults possible. RepairPal rates it 'Urgent' and lists the pump actuator, the pump itself, wiring and the PCM. On diesel engines with an injection pump, the fuel metering control 'A' is mounted on or inside the pump. OBD-Codes.com describes it as a fuel rack position (FRP) sensor plus a fuel quantity actuator: the sensor turns the amount of fuel the actuator is delivering to the injectors into a voltage signal, and the powertrain control module (PCM) uses it to decide how much fuel to give the engine. P0252 is the 'range/performance' version: the PCM stores it when that signal doesn't match what it expects for current operating conditions, even for a second, or looks wrong at key on. OBD-Codes.com says the cause can be mechanical or electrical. RepairPal explains it in terms of pump pressure: the fuel pump control actuator controls the injection pump's output pressure, and the PCM sets P0252 when it detects an incorrect signal from that actuator. OBD-Codes.com says the code applies to diesel OBD-II engines generally but shows up more often on some Mercedes-Benz and VW vehicles, and searches for it center on Dodge Cummins, VW TDI and Mercedes. Which part of the circuit counts as 'A' depends on the vehicle, so check its service information.

Q: Can I keep driving with P0252?

Drive with caution, fix soon. Get it checked soon. The sources differ here: OBD-Codes.com says severity depends on the failure, severe if it is mechanical but less severe if it is electrical because the engine computer can compensate, while RepairPal rates P0252 'Urgent' and says the engine may lose performance or stall. Since a stall can happen while driving, don't put off a diagnosis.

Reviewed 2026-10-26 · Based on 2 cited source(s)

What P0252 means

On diesel engines with an injection pump, the fuel metering control 'A' is mounted on or inside the pump. OBD-Codes.com describes it as a fuel rack position (FRP) sensor plus a fuel quantity actuator: the sensor turns the amount of fuel the actuator is delivering to the injectors into a voltage signal, and the powertrain control module (PCM) uses it to decide how much fuel to give the engine. P0252 is the 'range/performance' version: the PCM stores it when that signal doesn't match what it expects for current operating conditions, even for a second, or looks wrong at key on. OBD-Codes.com says the cause can be mechanical or electrical. RepairPal explains it in terms of pump pressure: the fuel pump control actuator controls the injection pump's output pressure, and the PCM sets P0252 when it detects an incorrect signal from that actuator. OBD-Codes.com says the code applies to diesel OBD-II engines generally but shows up more often on some Mercedes-Benz and VW vehicles, and searches for it center on Dodge Cummins, VW TDI and Mercedes. Which part of the circuit counts as 'A' depends on the vehicle, so check its service information.

Severity: can I keep driving?

Drive with caution, fix soon

Get it checked soon. The sources differ here: OBD-Codes.com says severity depends on the failure, severe if it is mechanical but less severe if it is electrical because the engine computer can compensate, while RepairPal rates P0252 'Urgent' and says the engine may lose performance or stall. Since a stall can happen while driving, don't put off a diagnosis.

Common symptoms

Check engine light on (OBD-Codes.com)
Decrease in fuel economy (OBD-Codes.com)
Decreased engine performance (RepairPal)
Engine may stall (RepairPal)

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Failed fuel rack position sensor, rated the likely cause (OBD-Codes.com)
Fuel injection pump actuator (fuel quantity actuator) failure (both sources)
Open, short to voltage or short to ground in the sensor signal circuit, or lost power or ground at the sensor (OBD-Codes.com)
Wiring issue (RepairPal)
Fuel injection pump failure (RepairPal)
Failed PCM, rated unlikely by OBD-Codes.com (both sources)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Check for technical service bulletins for your year, make and model first, since the issue may be known with a known fix.
Find the sensor connector on or beside the injection pump and look over the wiring and connector for scraping, rubbing, bare wires, burn spots or melted plastic.
Unplug the connector and check the terminals for burning or green corrosion. OBD-Codes.com suggests cleaning them with electrical contact cleaner and a plastic brush, letting them dry and applying electrical grease.
Clear the code with a scan tool and drive. If it doesn't come back, OBD-Codes.com says the connection was most likely the problem.
If the engine stalls or loses power, have it diagnosed promptly rather than continuing to drive it.

Typical fixes

Clean or repair corroded or damaged connectors at the pump sensor
Repair open or shorted signal, power or ground wiring
Replace the fuel rack position sensor / fuel quantity actuator if circuits test good
Replace the fuel injection pump if it is at fault (RepairPal lists fuel pump replacement as the common repair)
Replace and program the PCM only after the other parts are ruled out

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

OBD-Codes.com's test: key off, unplug the FRP sensor, then key on engine off and measure between the harness power and ground terminals; expect 12 V or 5 V depending on the manufacturer's spec, otherwise repair power or ground or suspect the PCM. Then measure the signal terminal, which should read 5 V; if not, repair the signal wire or suspect the PCM.
If all circuit tests pass and P0252 keeps returning, OBD-Codes.com points to the FRP sensor / fuel quantity actuator, and says the PCM can't be ruled out until that part is replaced. A replacement PCM must be programmed to the vehicle.
OBD-Codes.com stresses that mechanical as well as electrical faults can set this code, especially when it is intermittent, so don't stop at the wiring if the circuit tests pass.
The sources disagree on severity and focus: OBD-Codes.com rates electrical causes as not very severe and centers on the FRP sensor circuit, while RepairPal rates the code 'Urgent', lists stalling, and names the injection pump itself and fuel pump replacement as common repairs.

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Can I drive with P0252?

Maybe for a short time if the cause is electrical, since OBD-Codes.com says the PCM can usually compensate. But it calls a mechanical cause severe, and RepairPal rates P0252 'Urgent' and says the engine may stall, so get it diagnosed soon.

What is the difference between P0251 and P0252?

Both point to the same injection pump fuel metering control 'A'. P0251 is the general malfunction code, while P0252 is the range/performance code, meaning the signal is present but doesn't match what the PCM expects. OBD-Codes.com lists the same likely cause, a failed fuel rack position sensor, for both.

Is P0252 a diesel-only code?

Yes. Both sources describe the diesel fuel injection pump, and OBD-Codes.com says it applies to diesel fueled OBD-II engines.

Does P0252 always mean a new injection pump?

No. OBD-Codes.com recommends checking service bulletins, connectors and wiring first, then testing the sensor circuit. RepairPal does list fuel pump replacement as a common repair, so a proper diagnosis is worth it before buying an expensive pump.

Sources

Last reviewed 2026-10-26. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.