tach reads incorrect

[SStryker]

hi everyone, i have been enjoying this site for a while. i just sold my 1997 and purchased a 06 quad g56 and i really like this truck. everyithing works great on this truck except the tach, it first started out being off a few hundred rpm for about 10 minutes or so 3 or more times a day, now it is wrong almost all the time and at idle it usually reads 0 rpm and on the interstate where it used to read 2000 rpm it now is almost red lined. any help or thoughts would be greatly appreciated!!!

 

[C Caspary]

If other weird problems are not occurring, its probably not a crank or cam position sensor. Both went bad in my '99



Might be a bad "stepper motor" in the tach itself. The gauge needle presses directly on to the shaft of the stepper motor.



General Motors had a batch of bad ones in their 2004's. Most of the gauges in my 04 yukon had quit after being wildly erratic. Had too many miles on it to qualify for factory replacement under their customer satisfaction program.



My son found a service kit with instructions online, pulled the dash assembly, and soldered in the new motors (in the GMC, the entire dash gauge cluster is one big circuit board).



Problems solved!



Charlie

 

[AMink]

I've noticed that my 06's tach is doing weird things lately too. At idle, it jumps around, dropping to 300, then up to 600 or 700. The other day I was pulling my TT up a pretty good grade. The transmission shifted down and the tach was showing about 3600! I saw that and waited for a "BOOM" that never came. I knew it wasn't running that high just because of the sound and the speed I was going. It was probably more likely at around 2900 or 3000. Is there some kind of sensor or is a direct drive?

 

[rbattelle]

The tach is fed data from the ECM via the front control module, I believe. Like Charlie mentioned, if it's only the tach acting up I'd suspect a problem with the gauge itself.

Try a self test of the instrument panel. To do this, with the key in the OFF position, hold down the trip reset button and turn the key to RUN. You can then release the button. The whole dash should light up and the gauges sweep their ranges. Watch the tach carefully to see how it behaves.

Ryan

 

[SStryker]

Hi Ryan, Thanks for the note, just tried on truck and everything seemed to work fine except tach so looks like we need to replace tach. Is there a place where one can find all the ways to test and operate things as wouldn't have known about the test you suggested except from you? Like also just learned that you can lock truck running with second key by double locking from outside. Where does one learn these things except through TDR. Again thanks

Todd and Barry

 

[rbattelle]

Is there a place where one can find all the ways to test and operate things as wouldn't have known about the test you suggested except from you?

I'm not sure. I learned it here at TDR. It may be in the factory service manual (which I have), but I've never bothered to look for it.



Ryan

 

[PAllyn]

Mine is doing the same. Dodge diagnosed it and said that the tach is bad. The instrument cluster needs to be replaced but that it will take atleast a month to get one in... perhaps longer depending on what happens with all the changes that Dodge is doing.
I think this is just the beginning of our troubles getting service from Dodge... . Good Luck!

 

[Red_Rattler]

Yup, thats an 06 issue... . Lotsa posts on it

 

[lallen2018]

The tach on my '06 dually just started eratic behavior. What was the outcome? Did you have to install a whole instrument cluster or has a fix been found?

Thanks in advance

 

[JCockerill]

I got a New Cluster on my 06 with same problems after dealer told me it was my banks tuner. it WAS the cluster. take it to dealer and tell them it needs a new tach if still under warranty.

 

[MChrist]

Son of a ... ..... ! I just went out to my '06 and noticed that MY tach is reading 500 at idle, then 750, then 500 again without really changing idle speed. Is this what you guys experienced?

 

[AMink]

Son of a ... ..... ! I just went out to my '06 and noticed that MY tach is reading 500 at idle, then 750, then 500 again without really changing idle speed. Is this what you guys experienced?

That and when I accelerate and it drops a gear or two, it reads almost 4000! If that's what it really is, I have other problems.

 

[SStryker]

Tack reads incorrect on 06

Our experience is that we had to replace the whole cluster. Unfortunately the dealer has to do it as the odometer has to be done by them in order to keep the mileage consistent with the truck. It was about a $500. 00 fix a year and a half ago. The issue is that there is a computer in the instrument panel that has to be computed with the computer in the truck so you can't just go to a parts yard and get a used one as it has to programmed together otherwise the truck won't run. The dealer wants to keep the truck for a few days while they send it into the company to get it updated and verified. It wasn't the greatest experience.

 

[JFought]

yup 06 problem Dealer did mine!! i still had to twist their arm!

 

[timelessconstructionllc]

I am having the same issues. Why is there not a recall on the issue.

 

[SStryker]

Sorry I can't help you with the recall issue, just have heard a number of folks have had the same problem and the only way you can get it fixed is through the dealer as we tried a variety of other ways. I suppose if you were good a programing computers you could do your own otherwise I know of no other way of getting it done.

 

[JordanB]

Mine's been doing this for a few months now - also an '06. So it's just the '06s that have this problem? Is this because '06 was the first year of the redesigned 3rd gen interiors? Looks like I'll being leaving it alone as I don't feel like spending $500 or more. I just love spending $43,000 on a truck that winds up having some cheap ***** part fail that can only be replaced by replacing another more expensive assembly! My dad's '99 Grand Cherokee emergency flasher button on the steering column failed some years back. It wouldn't stay depressed thus the flashers remained on unless you used duct tape to hold the button down. The fix? Replace the entire turn signal/headlight stalk assembly! I don't remember the price now - somewhere around $100 I think. It's not the money that matters (though I do get teed off the overly inflated parts replacement costs) but the principle. I don't need an entire dash assembly or turn stalk. I just need one part, but because it saves a supplier and manufacturer 10 seconds to snap together a bunch of parts into one larger assembly I have to buy a lot more parts! How much money could this possibly save on each vehicle? I'd be willing to pay a good amount more for a vehicle that was designed to be serviceable and not have to worry about death wobbles, unit bearing hubs, weak u-joints and ball joints. Heck, Rams cost, what, $5,000 less than a comparable Ford or GM? Upgrading these trucks' weak links would probably be less than or at least no more than $5,000. Is this not a profitable proposition for Dodge or any other manufacturer? If they don't believe it is, what does their reputation cost in the long term? I'll stop ranting now... wait. . I do have some stupid exhaust rattle on my truck now. Oh never mind!

 

[lallen2018]

I have another question - if I let the tach go will it just die? Or is it the start of something else? I have been wanting to get a tuner, i. e. Edge or Banks Bullet & they have the gages/monitors. However, I have the C56 transmission and glancing at the analog tach is convient for shifting points when pulling a load.

 

[JFought]

(i seem to remember a post where a tdr guy "repaired, of fixed his tach... "
you guys might search real hard

 

[timelessconstructionllc]

i have searched real hard but i'm not finding anything or anyone who is willing/able to fix the tach on an 06. On 05's or earlier its no problem to find someone to fix a guage cluster but apparently 06's are a whole different story.



lallen2018 and jordanb: my tach has gone completely berzerk, it reads ZERO rpms when i let off the throttle and when i get on it it reads 4,000-4,500, it has not effected anything else that i can tell though, truck still runs great and sounds great (definitly not running at 4500 rpms) if ya'll figure anything out please let me know, and i will do the same. thank you.