29F3
High29F3 — HPFP Failure (High-Pressure Fuel Pump)
Description
What the Code Means
Code 29F3 points to a high-pressure fuel pump (HPFP) fault on N54 engines. The HPFP delivers fuel under high pressure to the direct-injection system. On early N54 versions this pump is a common problem due to design flaws. BMW revised the pump several times, and later revisions are considerably more reliable.
Symptoms
Symptoms
- Engine: stumbling under acceleration, sudden loss of power, long cranking, no-start
- Indicators: Check Engine Light (CEL) comes on
Causes and fixes
Diagnosis and Repair
Step 1: Read the Codes
Use ISTA to confirm code 29F3 and check for related faults.
Step 2: Check Fuel Pressure
Connect a gauge to the fuel rail and measure pressure. Compare against the reference values.
Step 3: Replace the HPFP
If pressure is below spec, replace the HPFP with the latest revision (genuine BMW 13517592429).
Step 4: Adaptation
After replacement, clear the adaptations and take the car on a test drive to verify.
Possible secondary damage
Secondary Damage
Ignoring the fault can lead to a complete HPFP failure, after which the engine won't start. Continuing to drive with a failing pump causes a lean fuel mixture, which can damage the catalytic converters and oxygen sensors.