Fuel and air

P0252 — Injection Pump Fuel Metering Control A Range/Performance

Severity: medium Drive with care, to a shop

What P0252 means

A diesel ECM controls how much fuel the injection pump delivers using a metering solenoid or actuator (circuit A). P0252 is set when the actual metering or the feedback signal does not match the commanded value or falls outside the expected range. The cause may be electrical, a worn pump, or a fuel supply problem.

Symptoms

  • Check Engine light on
  • Reduced power and sluggish acceleration
  • Rough idle or stalling
  • Hard starting, especially when cold
  • Higher fuel consumption
  • Increased exhaust smoke

Possible causes

  1. Faulty fuel metering solenoid or actuator in the injection pump
  2. Open, shorted or corroded wiring and connectors in the circuit
  3. Internal mechanical wear or failure of the injection pump
  4. Low supply pressure from a clogged fuel filter or weak lift pump
  5. Water or contamination in the fuel
  6. Faulty ECM (rare)

How to diagnose

  1. Read all codes and freeze frame data, and look for other fuel system codes
  2. Inspect the pump harness and connector for chafing, corrosion and poor contact
  3. Measure metering solenoid resistance and check power and ground circuits against the factory diagram
  4. Check fuel supply pressure and the condition of the fuel filter
  5. Drain the filter and check the fuel for water and debris
  6. Compare commanded and actual metering values in scan tool live data
  7. Check injector operation and cylinder balance
  8. If the electrical side is good, have the pump tested on a bench or by a specialist

Common fixes

  • Replace or repair the metering solenoid or actuator
  • Repair the wiring and connectors
  • Replace the fuel filter and correct supply problems
  • Replace or rebuild the injection pump if it has failed mechanically
  • Replace or reflash the ECM only after ruling out everything else

Questions and answers

What does P0252 mean?

It is a range or performance fault in the injection pump fuel metering control A circuit. The ECM sees that the pump is not delivering fuel the way it commands.

Can I drive with P0252?

Briefly, for example to a repair shop, but the engine may lose power or stall. Do not delay diagnosis, to avoid damaging the pump.

What should I check first?

Check the pump wiring and connector, the fuel filter, supply pressure and any water in the fuel. These are the simplest and most common causes.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.