Code 71 (1 Viewer)

[Gregb]

My 94 LC with 118K miles is giving me an error code 71. The engine runs as smooth as ever, I reset the code once and ran it for 100 miles or so and it came back. Code book lists the error as possible bad EGR temp sensor or EGR valve. I had throttle body service 5K miles ago. I hate to shotgun the parts, any suggestions on how to narrow it down a bit?

Thanks.

 

[elmariachi]

Code book lists the error as possible bad EGR temp sensor or EGR valve. I had throttle body service 5K miles ago. I hate to shotgun the parts, any suggestions on how to narrow it down a bit?
Thanks.

The FSM will tell you exactly how to diagnose each sub part affected by that code.

 

[super90]

One thing to look for, which the FSM doesn't explain, and which was the problem on my truck, is that there is a port that goes from the EGR valve along the top of the throttle body and opens up into the top of the throttle body. Mine was totally plugged up. I had my favorite independant do lots of tests trying to find the problem that was throwing the Code 71, but he couldn't figure it out, so I just pulled everything apart, replace the EGR and the VSV and all the vaccuum lines and gaskets, then noticed the plugged port while everything was apart !! Hey, at least my whole EGR system is new and will last another 100k ++ miles. Truck runs smoooooooth now with no vacuum leaks

Pull the air intake hose and look into the throttle body with a flashlight and maybe an inspection mirror and see if that port is plugged. That would be a ten minute fix.

FYI, I talked to Robbie at Slee's at length about what tends to throw the 71, and he basically said, there is no one thing that does it more than any other thing. It seems to be a different component of the system each time they fix it. IIFC, mine what the first one he had heard about having the plugged port.

Best of luck,

Robert Callaway
'94 FZJ
San Antonio, TX

 

[Gregb]

Thanks so much for the information Robert. I'll check that out tonight. Certainly has me baffled as the enigne still runs as smooth as ever.

Thanks again,
Greg

 

[Gregb]

Well Robert I took your advise and checked for clogged vaccum lines, and it turned out to be a disconnected vaccume line. It was below the throttle body, just above the transmission dipstick. No idea how it was disconnected, but that was all it was.

I did order a FSM from C-Dan, will use it in the future but I'd rather post this in the event someone else has a similar problem in the future. Much more helpful than simply telling them to check the FSM.

Greg

 

[landtoy80]

Gregb, have you seen my post in the FAQ section on the EGR?

 

[super90]

One thing I noticed, a lot of my vacuum lines were so hard that they really didn't hold on very well. Serveral of them could be removed with very little effort.

I ordered factory vacuum line and replaced them all, but some are in some spots that will be tough to get to without pulling things apart. I happened to have the intake off at the time.

Best of luck,

R.