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DTC codes / P26xx · Computer and output circuits / P2624

P2624Injector Control Pressure Regulator Circuit Low

P2624 indicates that the engine control module (ECM) has detected a low-voltage condition on the injector control pressure regulator circuit, which is used on diesel engines to manage fuel rail pressure. The ECM expects a certain voltage range on this circuit and sets the code when the signal falls below the calibrated threshold, often due to a short to ground or an open circuit.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaComputer and output circuits

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Rough idle or engine misfire, especially when cold
  • Reduced engine power or limp mode activation
  • Hard starting or extended cranking before the engine fires
  • Poor fuel economy or increased exhaust smoke

Common causes, most likely first

  1. Faulty injector control pressure regulator solenoid
  2. Damaged or chafed wiring harness causing a short to ground
  3. Corroded or loose electrical connector at the regulator
  4. Open circuit in the power or ground circuit to the regulator
  5. Failed engine control module (ECM) driver circuit
  6. Low fuel pressure or fuel system contamination affecting regulator operation

How to diagnose and fix it

  1. Perform a visual inspection of the regulator connector and wiring for damage or corrosion
  2. Use a digital multimeter to check for battery voltage at the regulator connector with the key on
  3. Measure the resistance of the regulator solenoid and compare to the manufacturer's specification
  4. Check for continuity between the regulator connector and the ECM to rule out an open circuit
  5. Test for a short to ground on the control circuit using a multimeter
  6. If electrical checks pass, test fuel pressure and inspect the regulator for mechanical failure
  7. Replace the injector control pressure regulator if faulty and clear the code with a scan tool

Don't overlook the wiring harness

  • A chafed wire behind the engine block or near the exhaust manifold is a frequent cause of this code that is often missed during visual inspections.
  • The code can be set by a failing fuel pressure regulator that is not electrically faulty but mechanically stuck, so electrical tests alone may not reveal the problem.
  • On some vehicles, a low battery or charging system issue can cause a false P2624 by dropping voltage to the regulator circuit during cranking.
  • Replacing the regulator without checking the connector pins for spread or corrosion often leads to a repeat failure and the same code returning.
  • This code is sometimes stored alongside P0087 or P0088, indicating that fuel pressure issues may be the root cause rather than the regulator itself.

Can I keep driving with P2624?

Driving with P2624 is generally not recommended because the engine may enter limp mode or stall unexpectedly, increasing the risk of an accident. If you must drive to a repair shop, avoid heavy acceleration and towing, and have the fault diagnosed as soon as possible.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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