2006 check engine light - need help

hankdz · **Posted:** Sat Jul 25, 2020 12:30 pm

Our 2006 KJ has engine check light on. A tech read the codes for me. They are:
- P0101 - MAF sensor "A" circuit;
- P0402 - EGR flow excessive; and
- P0674 - cylinder 4 glow plug circuit.
One other thing, after he read the codes he reset the light. He told me to drive it a while to see whether it came back on. It did immediately. Another thing, while driving it after he checked the light and reset it I stepped on the throttle to rev the engine up, i hadn't driven it for a few weeks. It almost died. No pick-up at all. The engine revved up in each gear, but it didn't shift properly. After that experience, I drove it like a normal person and it drove fine. It ran through the gears as expected, it climbed hills with no hesitation, and it just generally performed like normal. Then I tried running it hard again, same result as the first time.
Those are the facts.
What does each of those codes mean in practical terms? That is, what needs to be done to return the light to off permanently? Parts, etc. that need to be replaced? When the vehicle was still in warranty, the EGR gate was replaced at least twice. I bought it with 20,000 miles and it was replaced twice in about six months. I installed the SEGR gizmo before it was out of warranty which seemed to cure the gate failure issue.
I have cleaned the MAF sensors a few times. It has been a while since that was performed though.
The SEGR turn off gizmo is installed, and has been for years. However, I noticed that there was a noise coming from the passenger side engine compartment when I stopped for a light or idled for any length of time, such as when idling for a minute or two before shutting down the engine. That started a few weeks before the light came on. After the light came on I haven't used the vehicle much. It remained garaged for the past four months, except for an occasional foray just to turn the wheels and run it for ten minutes while I found someone to check the codes. Long story.
Does anyone know what I need to do? We love the little beasty and don't want to dispose of it with such low mileage.
Please help.

flash7210 · **Posted:** Sat Jul 25, 2020 6:15 pm

The glow plug code likely means a bad glow plug.
If you still have the factory original ceramic plugs you should replace all 4 with the Bosch 5v plugs.

EGR and MAF kinda work together.
The SEGR is meant to completely disable the EGR valve without setting a code.
So, we already know the EGR valve is closed and not causing a problem.
And we already know that unplugging the MAF sensor will not cause any problems other than setting a code.
Therefore, I dont think the SEGR is the problem.
Or, the SEGR has failed in some way. Like maybe a bad\loose wire connection or some component on the circuit board has failed and thats why you have the codes but shouldn't be a driveability problem.

The buzzing you hear on the passenger side is most likely the large vacuum solenoid that controls the turbo.
A problem there will definitely cause the engine to run poorly.

hankdz · **Posted:** Sun Jul 26, 2020 7:39 am

Thanks for the help. I’ve been looking at glow plugs and found an article on IDParts. It discusses 7v vs 5v plugs. Apparently Jeep had a “soft” recall to replace ceramic plugs with steel plugs. The ceramic were 7v, steel 5v. It went on to say that some folks on this forum ran the 5v plugs at 7v choosing not to reprogram the computer. Which did you do and how can I determine whether the computer in my Jeep has been reprogrammed?

flash7210 · **Posted:** Sun Jul 26, 2020 8:08 am

I dont know how to determine if yours has been programmed.
Probably safe to say that if you've never replaced the glow plugs they're still the 7v plugs.

I switched to the 5v plugs a couple years ago.
I did not do any reprogramming.
Been working just fine ever since.

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

flash7210 wrote:

I dont know how to determine if yours has been programmed.
Probably safe to say that if you've never replaced the glow plugs they're still the 7v plugs.

I switched to the 5v plugs a couple years ago.
I did not do any reprogramming.
Been working just fine ever since.

Same here. Changed them out for Bosch 5V units about 2 years ago, kept the 7V programming, and have had no issues.

There's been some back-and-forth regarding how this may potentially shorten the lifespan of the glow plugs, but nothing conclusive has really been found.

hankdz · **Posted:** Mon Jul 27, 2020 7:52 am

Thanks to all.
I bought the vehicle with 20,000 miles on it in 2008. It now has 128,000 miles. I don’t know what was done to it before I owned it. I guess I’ll just remove a glow plug to see what it is. If it is ceramic and 7v then I’ll know the system hasn’t been abused.
I will get back here later with the results of my investigation.

WWDiesel · **Posted:** Mon Jul 27, 2020 10:12 am

FYI:
IDParts has GP's on sale right now,

Quote:

Glow Plugs on sale for your Jeep! 100 Days of Summer Sale
http://bm5150.com/t/l?ssid=41041&subscr ... ENryOEXeSA

layback40 · **Posted:** Mon Jul 27, 2020 8:21 pm

WWDiesel wrote:

FYI:
IDParts has GP's on sale right now,

Quote:

Glow Plugs on sale for your Jeep! 100 Days of Summer Sale
http://bm5150.com/t/l?ssid=41041&subscr ... ENryOEXeSA

Its always perfect timing for those of us who are on the underside of the flat earth! Mid winter here.

hankdz · **Posted:** Sun Aug 02, 2020 1:57 pm

Hi, me again.
Thanks for the note about on sale glow plugs I looked into it. They have both 5v and 7v on sale.
Okay, I'm at the point where I need to look at one of the existing plugs. I watched one video that was posted in 2015. It showed access to the plugs from the alternator side of the engine. I have a question, not about the video, but about proceeding.
What do I need to remove to be able to see the plugs, and then remove one to see if it is a 5v or 7v?
So far I have removed the battery, and the hoses for my home made provent. That opened up a small window, but not enough to see the plugs. I also need to clean the MAF sensors and I need to get the large cable that is set on top of the engine out of the way to be able to access the rear sensor. I did that once before but I don't remember how to take the cable tray apart so I can move the cable. It has a series of clips that I can't seem to disengage.Much of this memory crap, or lack thereof, comes from age. I'm pressing against 80, but my rememberer seems to think I'm 20, then it reverts to real time and fails me. However, I can still make a mean martini - not those wimpy fruity things, but the real thing where I just pass the word vermouth over the glass. :}
Thanks again for the help so far, and any that is forthcoming now.

hankdz · **Posted:** Sun Sep 13, 2020 4:11 pm

I installed 7v from idparts. The original 7v ceramic were still in there. The #4 plug was cracked but it came out in one piece.
A mechanic reset the codes. The check engine light remained off for about 20 miles then it relit. I don't know what codes are showing now. I cleaned both maf sensors. I don't know which one is the "A" circuit sensor. However, when i took them out to clean them the one in the duct after the air filter didn't look dirty at all. The other was oily and dirty, but not sooty like when I first cleaned it many months ago. I guess the SEGR is working as it should.
At this point I am assuming the light came back on because of something other than the glow plugs. I am being real tempted to get a code reader/interpreter/resetter. Does anyone know whether the ones from harbor freight are worth while? I'm no mechanic, but I can change parts if I know which ones to change.

Thanks.

hankdz · **Posted:** Sun Sep 13, 2020 4:24 pm

I might have missed something. When the original mechanic read the codes, he wrote down the codes for me. His hand writing was not easily interpreted, so I assumed he wrote MAF when it might just as well have been MAP. I didn't know there was an MAP until just now when looking for parts. So, now its more critical that I learn what the code is telling me. Is it MAP or is it MAF? Some one please help. I guess it would be good to have a code reader/interpreter/resetter.

Thank you.

WWDiesel · **Posted:** Sun Sep 13, 2020 9:22 pm

hankdz wrote:

I might have missed something. When the original mechanic read the codes, he wrote down the codes for me. His hand writing was not easily interpreted, so I assumed he wrote MAF when it might just as well have been MAP. I didn't know there was an MAP until just now when looking for parts. So, now its more critical that I learn what the code is telling me. Is it MAP or is it MAF? Some one please help. I guess it would be good to have a code reader/interpreter/resetter. Thank you.

You can read any stored Pcodes using the key on and off method without a scanner to whit:

Enter vehicle, close all doors, turn the key to the last position "ON" (just before the car would start) and then back to "OFF" again - do this three times, on to off fairly quickly then leave it in the on position on the last (third) cycle and any current codes will display on your odometer one at a time in succession where the mileage is normally visible. Record the Pcodes shown and report them to LOST.
Members will advise from there.... :wink:

Billybob · **Posted:** Mon Sep 14, 2020 1:37 am

WWDiesel wrote:

hankdz wrote:

I might have missed something. When the original mechanic read the codes, he wrote down the codes for me. His hand writing was not easily interpreted, so I assumed he wrote MAF when it might just as well have been MAP. I didn't know there was an MAP until just now when looking for parts. So, now its more critical that I learn what the code is telling me. Is it MAP or is it MAF? Some one please help. I guess it would be good to have a code reader/interpreter/resetter. Thank you.

You can read any stored Pcodes using the key on and off method without a scanner to whit:

Enter vehicle, close all doors, turn the key to the last position "ON" (just before the car would start) and then back to "OFF" again - do this three times, on to off fairly quickly then leave it in the on position on the last (third) cycle and any current codes will display on your odometer one at a time in succession where the mileage is normally visible. Record the Pcodes shown and report them to LOST.
Members will advise from there.... :wink:

I believe that this "key" method of pulling codes does not work on the 2006 CRD and maybe/maybe not on the 2005 CRD.

WWDiesel · **Posted:** Mon Sep 14, 2020 2:07 am

Billybob wrote:

I believe that this "key" method of pulling codes does not work on the 2006 CRD and maybe/maybe not on the 2005 CRD.

Not sure on the 06, but it works on my 05, I have tested it!

Billybob · **Posted:** Mon Sep 14, 2020 8:29 am

Yeah I thought that the key method works on the 2005 CRD but was not 100% sure!

Pretty sure the Key method does not work on the 2006 CRDs....we need a 2006 CRD owner to chirp in here!

My 2002 Export CRD i can only get codes pulled by the Dealers with their DBII Reader or using the "key" method. The Dealers here are totally useless so I avoid them and have got by using the Key method.

Weird thing is it seems on Export models like mine I have to turn key ON/OFF rapidly 4 times to get the codes as apposed to the 3 times USA/Canada models require! :shock:

hankdz · **Posted:** Mon Sep 14, 2020 9:59 am

Hi.
I tried the "key" method. I tried 3 times and I tried 4 times. Neither worked.
Thanks for the hints though.
Looks like I need to get a code reader gizmo. I can't keep taking advantage of the mechanic who helped me the last time, it's his livelihood, and I don't want to abuse our friendship too much.
When I get the codes, I'll be back.
Thanks again.
Hank

WWDiesel · **Posted:** Mon Sep 14, 2020 12:22 pm

hankdz wrote:

Hi.
I tried the "key" method. I tried 3 times and I tried 4 times. Neither worked.
Thanks for the hints though.
Looks like I need to get a code reader gizmo. I can't keep taking advantage of the mechanic who helped me the last time, it's his livelihood, and I don't want to abuse our friendship too much.
When I get the codes, I'll be back.
Thanks again.
Hank

You can take it to one of the Auto Parts Stores like Auto Zone and they will read your codes for free.
Of course they will be glad to sell you a cheap code reader or you can order one off Amazon. There are plenty to pick from. :juggle:

2006 check engine light - need help

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