P2624 critical

Injector Control Pressure Regulator Circuit Low

The P2624 code means the vehicle's onboard diagnostic system has detected: Injector Control Pressure Regulator Circuit Low. This is a critical severity code.

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Keep driving?: No -- stop driving
DIY difficulty: hard
Estimated cost: $200 - $1200 (parts and labor)

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Common Symptoms

Low injection control pressure
Engine cranks but barely starts
Heavy white smoke on startup
Loss of power under acceleration

Probable Causes (Ranked by Likelihood)

IPR valve stuck open dumping pressure Very High
Short to ground in IPR control wiring High
High-pressure oil leak in HEUI system Moderate
Worn high-pressure oil pump Low

Step-by-Step Diagnostic Procedure

Monitor ICP pressure during cranking and idle
Test IPR valve for proper sealing
Check IPR circuit for short to ground
Perform high-pressure oil system leak-down test

Frequently Asked Questions

Can a stuck-open IPR cause white smoke?

Yes. Low injection pressure causes poor fuel atomization, resulting in incomplete combustion and heavy white smoke, especially during cold starts.

What is the HEUI system?

Hydraulic Electronic Unit Injection uses high-pressure engine oil to actuate fuel injectors. The system requires 500-3000+ PSI oil pressure to properly fire injectors.

How much oil pressure does the HEUI system need?

The system typically needs a minimum of 500 PSI ICP for starting and up to 3000+ PSI under full load. P2624 indicates the IPR cannot maintain these pressures.