Injector Control Pressure Too Low During Cranking
The P2291 code indicates that the Engine Control Module (ECM) has detected the injector control pressure (ICP) is below the minimum threshold while cranking the engine. This typically occurs in diesel engines with high-pressure common rail or HEUI injection systems. The ECM monitors ICP sensor voltage; if pressure doesn't reach the required level (e.g., 500 psi) within a specified time, it sets this code. Common causes include low oil level (for HEUI systems), faulty ICP sensor, high-pressure oil pump failure, or injector issues.
01. Most Common Causes
- Low engine oil level or incorrect viscosity
- Faulty injector control pressure (ICP) sensor
- High-pressure oil pump failure or worn components
- Clogged or leaking injectors
- Wiring or connector issues to ICP sensor
02. Symptoms You Will Notice
- Engine cranks but fails to start
- Long cranking time before start
- Rough idle or misfire after start
- Check Engine Light illuminated
03. Step-by-Step Diagnosis
Step 1: Verify engine oil level and condition; top up or change if necessary.
Step 2: Use a scan tool to monitor ICP sensor voltage during cranking; should rise above 0.5V.
Step 3: Inspect ICP sensor connector for corrosion or damage; test sensor resistance.
Step 4: Check high-pressure oil pump operation and pressure relief valve.
Step 5: Perform injector leak-down test to identify faulty injectors.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not safe. The vehicle may not start or may stall unexpectedly, leading to a breakdown or accident.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. Repairs vary: oil change $50-$100, ICP sensor $150-$300, high-pressure oil pump $500-$1500.