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

P2028

EVAP Fuel Vapor Temperature Sensor Circuit Intermittent

The EVAP fuel-vapor temperature sensor signal jumps or drops out intermittently — usually a connector or chafed wire.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / 28

Possible causes

  • Intermittent connector or chafed wire high
  • Connector with intermittent contact under vibration low
  • Harness routed against vibrating component low

Symptoms

  • Check engine light on
  • Possible smell of fuel near tank or engine bay
  • Failed emissions inspection
  • Loose-cap warning may appear

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 30–300 €
  • Estimated time: 0.5–2 h
  • Component: evap fuel vapor temp sensor
  • Component: evap harness
  • 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