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

P2511

ECM/PCM Power Relay Sense Circuit Intermittent

The sense (feedback) line that lets the ECM verify the main power relay has actually closed shows intermittent dropouts. The ECM expects to see battery voltage on this line whenever the relay is energised — short losses suggest aged contacts, vibration or chafed wiring.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 11

Possible causes

  • Aged main relay contacts high
  • Chafed sense wire shorting intermittently medium
  • Connector with intermittent contact under vibration low

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 60–400 €
  • Estimated time: 0.4–1.5 h
  • Component: main relay
  • Component: sense wire
  • MIL / check engine light

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