ok for about a week now my engine light has been coming on and going off by its self at completely random times, i used my hypertech to check from DTCs and the first time it didn't show any, the second time it happened, i checked it and this time i got P0405, which is EGR Position Sensor Circuit Low.

the next day the light had gone off and i drove for about an hour 1/2 on the highway, once i got off about 5 min later it came back on, but again the next day it had gone off again by its self, and then again tonite when i went out to grab dinner, it came on again, not sure if these past 2 times are still throwing the same code about the EGR,

my question is, why would it be comming on and turning its self off so frequently and randomly?

What is the EGR sensor? what does it do?

being down at school its hard to find time to goto a dealer unless im home for the weekend. and its something im trying to avoide having to do.

let me know guys and gals.
thanks



p.s. this all started happening after my rear passenger side corner was struck by a telephone pole.... dont ask

 

I'll take a stab at your questions.

The EGR Position Sensor does as the name implies. It tells the computer what position the Exhaust Gas Recirculation Valve is in.

The code you quoted is a "one trip fault". That means it will set a code immediately.

In the troubleshooting chart, it asks if the Diagnostic Trouble Code is active, Yes or No. This makes me think the code is present only when the fault is taking place.

Most of the probable causes for this fault code are various open circuits or shorts to ground as related to the EGR Solenoid.
A bad solenoid, and a bad Powertrain Control Module are the last two possibilities.

Being intermittent, my first guess would be a loose wire somewhere in the vicinity of the EGR valve.
Your best bet is to take it to the dealer since it is covered under warranty. The fact it started when the pole hit your fender could indicate a wire was jarred loose up front. Could be a coincidence.

 

i hope just knocking it loose is the case. u got me worried now, being that this sensor has to do with the exhaust, i hope i don't take any flack from the dealer for changing out my stock exhaust. but then again i don't see why that would be a problem.

thanks for the info, very helpful

 

You left out that little detail.
Where does the after-market exhaust begin? If the front half is stock, it should not be a factor.

 

the new muffler is installed so that it ends just before the stock evap location, its the cooltech kit. i had been fine for weeks, this only started after the hit.

 

Not a factor, imo.

 

yeah i wouldn't have thought so either, well I'm taking it in first thing in the morning.

thanks a bunch for your help.

 

k got back from the dealer, they told me i need to replace the sensor for $322.70

didnt ask the tech the importance of the sensors position, but as long as the valve is working it shouldnt be that big of a deal right?

they also tried to get me for $458 to replace the rear brakes (rotors and all) b/c they "need replacement in the near future" i chukled at that one, its a do it your selfer for me.

and he also tried to get me for diff oil change for $290 which ive already taken care of for $60

I love my stealership