The engine light came on with my '04 X-type 3.0 a couple of weeks ago. Someone read the codes and said I had 171 abd 174. I read a number of the suggestions on the forum for these codes and then cleaned the MAF and sprayed propane around the engine compatment but didn't notice any change in the RPM.

If I put soapy water on all the vacuum lines, how will I know if I stopped up a leak?

Thanks.

Bob

 

Bob, based on your codes, you have 1 of 3 issues. I would first check the hose running from the PCV valve to the intake manifold (the underside will split where the hose goes up and over the bracket there). Next, follow the line going from the top of the intake manifold to the brake booster. IN the middle of that line, there is a bulge (this is a check valve). The bulge is known to get flaky and crumble into dust when it starts getting old due to heat. It will then start to crack and leak. If you can see dust coming off of the bulge when you rub it, time to replace it. The final spot is the IMT o-rings on the passenger side of your car. If you look at the side of the intake, you will see 2 black circles about 4" in diameter. Under each disc is an o-ring that is known to leak after aging. You can spray some starter fluid on the joint and if you hear the RPMs pick up, then you know the o-ring is leaking by and needs to be replaced.

If you are still having issues, then let me know and we can take things from there.

 

Bob: Also check the underside of the bellowed hose between the MAF and throttle body. This too can crack from engine heat when it gets old, and perhaps too much flexing when changing the air filter and / or spark plugs.

 

Bob, you'll need to do the big three culprits eventually so check to see if they've been done already. If not, do them. A new PCV hose will be ribbed rather than smooth. Brake booster check valve will be encased in shrink wrap rather than exposed white plastic. IMT o rings will be green rather than yellow. All relatively cheap to do.

dwclapp, good call on that bellowed portion of the air intake. Not sure why more haven't gone bad yet due to age.

 

Hey Bob,

I had the same codes on my 03 X. I disconnected the vacuum hose and blew cigar smoke into the intake. on the top of the intake is a small grommet that was just barely leaking a very small amount of smoke. I sealed up the grommet and the codes cleared.
Maybe its as simple a fix as that. Its certainly worth a try.

 

Scotty Kilmer shows how to find a vacuum leak with cigar smoke in this youtube video:

 

Thanks Thermo, dwclapp and mohrd for your suggestions.

I changed the old yellow 0-ring on the upper IMT but I don't see how to remove the lower MT without removing either the intake manifold or the black plastic housing that's just to the right of the IMT. Which is the easier to do or is there some way that's not necessary?

Also, since I don't have the diagnostic instrument to clear the codes, how will I know if I've found the leak and fixed it? How long does it take the car's computer to clear the codes on it's own?

Thanks for your help.

Bob

 

Bob, for the lower unit, you have 2 choices. The first one you talked about with removing the intake and accessing that way. Lots of work (about an hour total), but then you can install the o-ring like it should be. Option #2 is to remove the 2 bolts holding the lower unit in place and then using a small scribe or other device to get under the o-ring, lift up on the o-ring (stretching it slightly) and then stretch it over the end of the IMT valve so you can pull it off. Then you can take the new o-ring and slide it under the IMT valve and then stretch it slightly to get it over the flange. From there you can set it into its proper position and re-install everything.

As for clearing codes, you have 3 options here:

1) if you drive the car 5 times for about 10 minutes (min) each, on the 6th time you start the car, the CEL will clear itself provided that the conditions that caused the code have never appeared during the previous 5 drive cycles.

2) disconnect one of the battery terminals, wait a minimum of 30 seconds and then reconnect the battery. BEWARE!!!!!! This will also clear any memory in your radio and you will need to reset your windows to restore the 1 touch feature.

3) pull all fuses associated with the ECM, wait 30 seconds, then reinstall them. You will loose your tripometer info, but that is it.

Once the applicable reset procedure has been done, if the CEL comes right back on (or on at a later time), you have either not cleared the condition causing the code or you have a new/different code.

 

Bob: Don't get discouraged if the old, yellow O-ring tears and breaks when you stretch it over the lower IMT valve to remove it. Age and heat robbed the old O-ring of it's elasticity. The new, green O-ring should be elastic enough to stretch and slide over the IMT valve when you install it. I purchased a spare O-ring just in case, but didn't need it.

 

I've replaced the two IMT 0-rings and the ribbed rubber hose connected to the PCV valve. I've sprayed propane all around a 2nd time but got no increase in RPM.

What should I look at next?

My gas mileage has only dropped about 5% since this problem started; from 20.5 to 19.5.

Should I look at how the fuel supply could be reduced: clogged fuel filter, etc.?

Thanks.

 

Since you changed the PCV hose and changed the IMT O=rings are you still getting those same codes? You still need to check the brake booster hose. See Thermo's original response.

 

Alfadude,

I don't know how to reset the codes, so all I know is that 4 or 5 days of driving haven't caused the CEL to go out.

The brake booster hose check valve looks to be in great shape, but I'll replace it if you still think it could be faulty.

Bob

 

If you look up at one of the earlier posts from Thermo he mentions options to clear the codes. You may not have had enough driving cycles to clear them yet or you could still have an issue. Best to clear the codes and if anything pops up again have them read. Is the car otherwise driving ok, or does it still feel like there is an issue?

Might not be a bad idea to change the brake booster hose. It isn't expensive and easy enough to do for the pieces of mind.

That difference in mileage does not seem very significant. Could just be a couple of longer trips, where you bought your gas or even the temperature going down a bit.

 

I disconnected the negative battery terminal for about a minute but the CEL didn't go out and the radio presets didn't change. Should I do something else to clear the codes?

I'd try pulling fuses instead but I don't know which fuses are associated with the ECM.

Thanks.

 

Bob

It may be worth your while to purchase a reader that will help you keep up on your codes and reset them, as needed. This thread has several inexpensive models listed and is on this forum to boot.

https://www.jaguarforums.com/forum/g...-%2A%2A-33347/

 

Bob: Major auto part stores will read error codes for free, but they typically won't erase the codes and turn off the CEL, because some people abuse this to pass an annual emissions test without fixing the real problem.

But a good mechanic typically will turn off the CEL for free or a nominal fee, if you explain that you already repaired the problem and simply need to erase the codes to confirm the repair was successful.

 

Thanks for your recent posts.

I disconnected the negative terminal of the battery again, for 2+ hours and the CEL is still on and the radio persets are still as I set them. ???? The clock of course lost time but that's all.

 

Bob, without knowing what codes you currently have I don't know what to tell you. As someone suggested you can go to one of the auto parts chains and have the codes read. You can also check the brake booster. You never mentioned how the car is driving? Is it running fine or do you have issues? Is it better, worse or the same as it was before you changed the IMT O-rings and PCV hose?

 

The car is generally running the same as it was before the 0171/0174 codes, but twice the car stumbled when trying to accelerate quickly.

Would pulling the right fuses be any more effective in reseting the CEL and the codes than disconnecting a battery terminal, or is the effect the same - no juice to the car's computer?

 

I doubt it, but obviously you haven't cured the situation yet. You might want to have the codes reread to see if anything else popped up since you worked on it.

Might want to consider taking in for a smoke test.