OBD Codes List

Diagnostic reference · P04E8

P04E8

EGR Temperature Sensor D Circuit High

System
Auxiliary emission controls (P code)
Lamp
Check Engine Light
Category
Powertrain - Auxiliary Emissions Controls

What it means

P04E8 stands for EGR Temperature Sensor D Circuit High. P04E8 is a P code, so the fault sits in the engine, transmission and emissions systems. For P04E8, the second digit places it in auxiliary emission controls. For P04E8, work through the cause list below, cheapest checks first.

Where it lives

For P04E8, the sensor sits on the circuit this code reports. The description of P04E8 reports a fault at the sensor.

What to check first

For P04E8, pull the connector and inspect the terminals for spread, corrosion or backed-out pins before testing anything else.

Check these first

  • P04E8: Carbon buildup or blockage in the EGR, EVAP, or air injection system
  • P04E8: Failed solenoid, valve, or pump in the auxiliary emissions circuit
  • P04E8: Wiring, connector, or fuse fault for the emission component
  • P04E8: Small leaks in vacuum or EVAP lines
  • P04E8: Failing catalytic converter or oxygen sensor reporting incorrectly

What to do next

P04E8 belongs to the auxiliary emission controls system. These are the general steps for P04E8, and the exact cause on your vehicle can differ.

  1. P04E8: Read related codes and freeze frame with an OBD-II scanner
  2. P04E8: Inspect hoses, valves, and solenoids for leaks, cracks, or carbon buildup
  3. P04E8: Smoke test the EVAP or intake system if a leak is suspected
  4. P04E8: Command components on/off with a scan tool and watch them respond
  5. P04E8: Clean or replace the blocked or failed component

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Updated

Generic SAE J2012 definition. Last updated 2026-08-30.