OBD Guide
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P1556

Charge Pressure Negative Deviation

P1556 is an OBD-II diagnostic trouble code meaning: Charge Pressure Negative Deviation. Common causes: air leak in the intake tract, turbocharger malfunction. Estimated repair cost: $17–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–167 (est.)

Symptoms

  • Reduced engine power
  • Increased fuel consumption
  • Unstable idling
  • Slow throttle response
  • Noise or whistle from the engine compartment

Causes

  • Air leak in the intake tract
  • Turbocharger malfunction
  • Bypass valve clogged or faulty
  • Problems with vacuum hoses or solenoids
  • Boost pressure sensor malfunction

How to Fix

  1. Check the tightness of the intake tract
  2. Diagnose the operation of the turbocharger
  3. Check the condition of the bypass valve
  4. Inspect vacuum hoses and connections
  5. Check boost pressure sensor

Related codes

P0234P0299P2262

Error P1556 by Vehicle Brand

BMWVolkswagen

FAQ

What does the P1556 code mean?

P1556 is an OBD-II diagnostic trouble code that indicates: Charge Pressure Negative Deviation

What causes a P1556 error code?

The most common causes of P1556 include: Air leak in the intake tract; Turbocharger malfunction; Bypass valve clogged or faulty; Problems with vacuum hoses or solenoids.

How do I fix a P1556 diagnostic trouble code?

To fix P1556: Check the tightness of the intake tract. Diagnose the operation of the turbocharger. Check the condition of the bypass valve. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1556?

Limited driving only, diagnose soon

How much does it cost to fix P1556?

The estimated repair cost for P1556 is $17–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat