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TuningBot DTC Database · v4.37.15

P01A4 Alternative Fuel Rail Pressure Sensor Performance

Generic (OBD-II) interpretation in the TuningBot DTC database.

P · PowertrainFuelOBD2

What P01A4 means

P01A4
Alternative Fuel Rail Pressure Sensor Performance Generic · fuel Data confidence 65%

The control module judged the Alternative Fuel Rail Pressure behaviour implausible for the current operating conditions.

Symptoms

  • Possible hard starting or long cranking
  • Possible reduced power or cutting out
  • MIL illuminated

Possible causes

  • Low-pressure fuel supply fault (pump, filter, lines)
  • High-pressure pump wear or fault
  • Pressure regulator / volume control valve fault
  • Fuel pressure sensor fault
  • Internal leakage (injector return flow too high)

Recommended checks

  • Read specified vs actual rail pressure at cranking, idle and load
  • Check low-pressure supply (pressure/volume) first
  • Check control valve/regulator operation
  • Measure injector return flow where applicable
  • Inspect wiring and connectors of pressure components

Related and nearby codes

Related codes
P01A3P01A5P01A6P01A7
P01 range
P0100P0101P0102P0103P0104P0105P0106P0107P0108P0109P010AP010BP010CP010DP010EP010FP0110P0111

How to read P01A4

P

Powertrain: engine, transmission and driveline systems.

0

Generic SAE-standard code: same meaning on every make.

1A4

Specific fault index within the subsystem.

Frequently asked questions about P01A4

What does P01A4 mean?

Alternative Fuel Rail Pressure Sensor Performance. The control module judged the Alternative Fuel Rail Pressure behaviour implausible for the current operating conditions.

Is P01A4 generic or manufacturer-specific?

P01A4 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove P01A4 at file level?

If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry. Checksum correction is not included: it is a separate, optional service. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.

Other file services

Stage 1/2/3 TuningDPF RemovalEGR RemovalAdBlue / SCR RemovalDTC RemovalIMMO OFFSpeed Limiter (Vmax)

Understand the system behind this code: Diagnostic Strategy and DTC Logic

ECU tuningDyno-tested results by model and engine See the results →

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