OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P01B6

Alternative Fuel Rail Temperature Sensor Circuit Low

Alt fuel rail temp sensor signal voltage below expected range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / B6

Possible causes

  • Signal wire shorted to ground high
  • Connector pins corroded - high contact resistance low
  • Harness chafing through insulation low

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 80–500 €
  • Estimated time: 0.5–2 h
  • Component: alt fuel rail temp sensor
  • Component: sensor wiring
  • MIL / check engine light
  • emissions-relevant

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication