/// Please help me with limp mode and error codes ///

Hi All,

Car's been running great and am currently at about 313K mile BUT a couple weeks ago the car threw 2 error codes that I've seen before (a P00674 and a P0252 .... I hope I got that right from memory on the walk back from the car).

Anyways, on occasion , I have seen these codes before and the car has gone into limp mode before but after awhile it went back to "normal" (i.e. running well) despite the engine light staying on ....

The other day, I was running up the mountain and the car lost power again....I figure the old codes were coming back to haunt me so I used my scan gauge to clear them out and I over to shut the car off for a bit (the thinking was the scan gauge would clear the codes and maybe shutting off resets something ?).

Anyways, that did not work ....still seemingly in limp mode so I drove home slowly..sigh

The next day I tried driving the car and same thing ...no overnight cure ! Yes, I know wishful thinking BUT it used to work .....I think!

Anyways, I cleared codes and drove again ....same issue (low power).

Desperate I drove to the dealer to get the pros to look at it (I know dealers UGH BUT I had a friend of a friend working there and he always did things for low $$ and sometimes free!).

I too the car in but was disappointed to learn this person was not there and had not been there for some time ..... I grudgingly let another tech look the car over ....

The diagnosis was I needed a new fuel injection pump and rear brake work .... They wanted $2800 !

I took the car back from the dealer and figured I'd ask for help here

I have seen the codes before BUT it always seemed to work itself out....It's not doing it this time tho.

Any "tricks" to get my car back to usable ? (basically low on power won't rev up ) ... no unusual noises or smells ....no wheezing from tailpipe so assuming exhaust and cat care not plugged up.

I think my fuel is OK since if it had water in it I would assume it would run rough and smoke alot ....no real smoke to mention.

Thanks in advance for any and all help.

Andrew

Thoughts

Your engine is an ALH...have you ever had the intake cleaned?

No actually not .... I actually have a spare one sitting in the shed I could make sure is clean and swap them out just in case....

I did have a Malone tune with dynamic EGR (EGR only on to warm up engine quickly then shut off) so hopefully not too much build up BUT it was run for 2ooK before I got the car (they claimed bio diesel so not sure if that is good or bad from an intake standpoint).

I'll check it out ....

Thanks for the input ... after 313K miles I'm sure it deserves a good intake cleaning! ;-)

P0674 is glow plugs, no issue, just needs fixed.
P0252 doesn't look right.
Further diagnostics is necessary. We haven't much to go on.
Good choice walking away from that dealer. At that mileage the IP could be pretty wore out, but may not be the issue.

The most common cause for limp mode when driving in the mountains, is the Mass Air Flow sensor (MAF) is gone bad. A very easy test is to turn the engine off and restart. Carefully if you want to do it on the fly. If you power comes right back, you can lay odds it the MAF.

You can try to clean the MAF by washing the works with CRC MAF cleaner or for 1/2 the price, Starter Fluid smells exactly the same as the CRC stuff

We stock MAF's by Peirburg or Bosch. They are the best.

I have a BEW with ~300k on it as well. I used to get limp mode, sometimes accompanied by an underboost/overboost CEL (can't remember which). Turned out the big rubber pipe/hose that connects to the intake, then runs down to, I believe the intercooler, was worn out where it connects to the intake. I got the dogbone mount mod for it and that pretty much fixed the issue. I have to really, really floor it up a mountain to get limp mode now, like muffler-melting power for a little while. Around the same time, I also fixed an issue with the brakes getting stiff intermittently which was apparently caused by a loose part at the nipple of the vacuum pump. I cut a hole in a ziplock bag, put the pipe through it, and put pipe clamps on both sides so it seals the gap (ghetto I know, but it worked). I can't say if it was one or both of these, but as I said, the problem has essentially disappeared since those two fixes. The nipple issue is easy to diagnose by wiggling the hose that connects to it while it's running, you should hear a whistle if it's problematic, and the intake hose wound up spraying oil all across the underside of the hood in a line parallel to the leaky circumference of the joint. Forgive me for being rather long-winded. Hope this helps