CODE: 31 (KOEO) - EVP circuit below minimum voltage. Vref missing or broken wire or bad contact in circuit. Check for 5 volts on the orange/white wire. With the sensor removed from the EGR and still connected, press the plunger and watch the voltage change on the brown/lt green wire. Use the black/white wire for the voltmeter ground. Check for the same results on pin 27 on the computer. Check for continuity between the wiring at the sensor and the computer. The brown/lt green wire on the sensor & pin 27 should be less than 1 ohm. The black/white wire on the sensor & pin 46 should be less than 1 ohm. The orange/white wire on the sensor & pin 26 should be less than 1 ohm.
yeah, I Cleared the codes using the scanner and I disconnected the Battery for 30 mins to try and get the hard codes cleared and I still get 31. Any ideas, the check engine light has been coming on alot, mostly when getting off the Freeway.
Same problem...I replace all the EGR crap and I am still getting code 31...and the check engine light. Are you running a little hot? EGR stuck in the closed position should result in hotter engine temps (also a problem I have). I am going to clean it again.
Read jrichker's post above guys - it gives you a step by step on what to do to determine where the problem is. The bits you've replaced aren't the problem - "Vref missing or broken wire or bad contact in circuit." That's the problem. The diagnostic above is straight from an authorized ecu trouble shooting guide. He knows his stuff - check out the rest of the circuit/wiring/connections.