Common causes for Code 71?

[ILikeCarsYesIDo]

Skimming through the TSRM, Code 71 has to do with a malfunction of the EGR system.

Diagnosis

* EGR gas temp below predetermined level during EGR operation.
* Open circuit in EGR gas temp sensor signal (THG).

Trouble Area

* EGR system (EGR valve, EGR hose etc.)
* EGR gas temp sensor circuit
* EGR gas temp sensor
* VSV for EGR circuit
* VSV for EGR
* ECU


Those of you who have experienced Code 71, what were your causes?

 

[jetjock]

I've never had it (my car isn't so equipped) but the causes are just what the book says. The ECU expects to see a certain temp rise from the EGR sensor when EGR flow is commanded. A lack of that rise could be electrical in nature (bad sensor, open wiring) or a lack of EGR flow to cause it (inop valve, cracked vac hose, plugged passage, etc).

 

[ILikeCarsYesIDo]

Thanks JJ. I will look into it further.

 

[isnms]

Sensor not connected
Air leaks, cracked flanges

What jj said

 

[Zumtizzle]

is it connected? It's in a odd place, and eazy to miss.