P0253
Injection Pump Fuel Metering Control A Low
If your vehicle's onboard computer has flagged the diagnostic trouble code P0253, it refers to a detected anomaly regarding "Injection Pump Fuel Metering Control A Low". This systemic engine fault needs a targeted check before symptoms expand.
Driver's Summary
Storing code P0253 is your car's way of telling you something is wrong with the injection pump fuel metering control a low. In practice, this fault causes engine stalling, hard start, lack of power. Given the high severity of this code, continuing to drive risks significant mechanical damage. Have it diagnosed immediately.
Symptoms
Engine stalling, hard start, lack of power
Common Causes
- Short to ground in metering control circuit
- Failed fuel injection pump
- Wiring damage
- Defective PCM
How to Fix
- 1 Trace and repair short to ground
- 2 Replace fuel injection pump
- 3 Repair wiring harness
- 4 Replace PCM
Technical Explanation
The ECM detects code P0253 by continuously monitoring the relevant sensor circuit against calibrated threshold values stored in its non-volatile memory. The PCM monitors crankshaft rotational velocity via the CKP sensor at a resolution of individual tooth gaps on the reluctor ring. A combustion event in each cylinder produces a measurable acceleration spike; its absence or weakness is flagged as a misfire event within a 200-revolution or 1000-revolution test window. The fault remains stored in memory even after the MIL is cleared; it becomes a confirmed DTC after failing two consecutive drive cycles, and the PCM logs a freeze frame record of the engine's exact operating state at the moment of detection.
Is It Safe to Drive?
This fault carries real mechanical risk. The root causes — including short to ground in metering control circuit — can trigger a chain reaction of component failures if the vehicle continues to be driven. Have it towed or drive directly to a shop without delay.
Mechanic's Pro Tip
Before replacing any component on P0253, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Wiring repair: 100; Pump: 1,000 - 2,000