What are the common causes of P229D?

A fuel pressure regulator B that runs above its learned limits. A clogged fuel return line. A stuck closed regulator B. A restriction in the fuel return path.

Read fuel pressure regulator B learned limits on a scan tool. Inspect the fuel return line for a restriction. Verify rail pressure with a mechanical gauge. Test the fuel pressure regulator B for a stuck closed position. Replace the fuel pressure regulator B if pressure stays high. Clear the code and retest.

P229D

Fuel Pressure Regulator B Exceeded Learning Limits - Too High

System: Injector circuits (P code)
Lamp: Check Engine Light
Category: Powertrain - Fuel/Air Metering

What it means

P229D means Fuel Pressure Regulator B Exceeded Learning Limits - Too High.

Check these first

A fuel pressure regulator B that runs above its learned limits
A clogged fuel return line
A stuck closed regulator B
A restriction in the fuel return path

What to do next

Read fuel pressure regulator B learned limits on a scan tool
Inspect the fuel return line for a restriction
Verify rail pressure with a mechanical gauge
Test the fuel pressure regulator B for a stuck closed position
Replace the fuel pressure regulator B if pressure stays high
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.