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

P2495

EGR Cooler Bypass Position Sensor Circuit High Bank 1

Same as P2492 with the signal voltage above the plausible range. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / 95

Possible causes

  • Signal shorted to supply high
  • Connector pins corroded - high contact resistance low
  • Supply wire pinched against B+ source low

Symptoms

  • Check engine light on
  • Pinging or knocking under load
  • Power loss and hesitation
  • Possible rough idle
  • Failed emissions inspection (NOx)

Inspection / repair

  • Difficulty: medium
  • DIY: possible

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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