Tach problem on my Avalanche.

[Buoy]

I have a 2004 Chevy Avalanche 2500. 4x4, 8.1 ltr.
Yesterday had all tires replaced, and alignment done.
Today, (first I've really driven the truck since having the work done) on my way to work, running down freeway ~65-70mph, I glance down at the gauges, and my Tach is reading 6000 rpm. Now, I know I would have noticed this just by the sound of the motor, but it still freaked me out. Stopped at a stop light, motor is idling just fine, everything is normal, but Tach is reading 4000 at idle.
Truck shifts as normal when accelerating. Turn truck off, and Tach remains reading at 4000.
All other gauges are right where they should be. (oil temp, trans temp, etc...)
So for you mechanical gurus, what is causing this, and how do I fix it?
Seems like this should be something fairly simple.
I certainly don't think the tires and alignment would have anything to do with this, but I wanted to mention it so as not to leave any info out.

[Bobcat]

I wonder if they pinched something (wires) when they put it on the lift.

[BUIZILLA]

there is a bulletin about this, your not the first...

[inbetween]

there is a bulletin about this, your not the first...

won't be the last either

[Airpacker]

you need a compatible scan tool to verify the correct signal from the powertrain control module (PCM) to the instrument control module (ICM). Odds are your tach is pooched but scan data of the rpm signal would be the best and quickest way to prove it. A tech2 scan tool can be used in bi directional mode to operates the gauges and verify that end of it.
The tach does not receive a signal from the coil like the OLD days. Its info is purely digital on the network and requires the ICM to decode it and move the tach needle accordingly.

[fund razor]

My truck doesn't have a tach.
God knows what could be happening in there.

[Ted]

My present to you, hope you fall in the year/mileage breaks:

Document ID# 2037454


Subject: Special Coverage Adjustment-Instrument Panel Cluster Gauge Needle Functions #07187A - (11/08/2007)



Models: 2003-2004 CADILLAC ESCALADE, ESCALADE ESV, ESCALADE EXT

2003-2004 CHEVROLET AVALANCHE, SILVERADO, SUBURBAN, TAHOE

2003-2004 GMC SIERRA, YUKON, YUKON XL


THE SERVICE PROCEDURE IN THIS BULLETIN HAS BEEN REVISED. IN A SMALL NUMBER OF VEHICLES, THE GAUGE SWEEP TEST MAY NOT ALWAYS CONFIRM THE CONDITION. PLEASE REVIEW THE SERVICE PROCEDURE IMMEDIATELY.


DUE TO PART AVAILABILITY, THIS SPECIAL COVERAGE IS BEING ADMINISTERED IN PHASES. YOU WILL BE NOTIFIED AS EACH ADDITIONAL PHASE IS RELEASED.

CUSTOMERS ARE BEING INSTRUCTED TO CONTACT THE DEALERSHIP TO ARRANGE AN APPOINTMENT IF THEY BELIEVE THEIR VEHICLE HAS THIS CONDITION. THE CUSTOMER IS BEING ASKED TO PROVIDE THE VIN SO THE IPC CAN BE ORDERED IN ADVANCE OF THE SCHEDULED APPOINTMENT. THIS WILL ELIMINATE THE NEED TO KEEP THE VEHICLE OVERNIGHT. DEALERS ARE TO OBTAIN THE VEHICLE MILEAGE WHEN SCHEDULING A SERVICE APPOINTMENT. THE VEHICLE MILEAGE WILL BE REQUIRED WHEN PLACING AN ORDER FOR THE IPC.

Condition
Some customers of 2003-2004 model year Cadillac Escalade, Escalade ESV, and Escalade EXT; Chevrolet Avalanche, Silverado, Suburban, and Tahoe; and GMC Sierra, Yukon, and Yukon XL vehicles have reported that one or more of the instrument panel (IP) cluster gauges stick, flutter, or become inoperative. This may cause inaccurate readings, including the speedometer and fuel gauge.

Special Coverage Adjustment
This special coverage covers the condition described above for a period of 7 years or 70,000 miles (110,000 km), whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership.

Dealers are to replace the instrument panel cluster after the condition has been verified. The repairs will be made at no charge to the customer.

For vehicles covered by Vehicle Service Contracts, all eligible claims with repair orders on or after September 28, 2007 are covered by this special coverage and must be submitted using the labor operation codes provided with this bulletin. Claims with repair orders prior to September 28, 2007, must be submitted to the Service Contract provider.

Vehicles Involved
Involved are certain 2003-2004 model year Cadillac Escalade, Escalade ESV, and Escalade EXT; Chevrolet Avalanche, Silverado, Suburban, and Tahoe; and GMC Sierra, Yukon, and Yukon XL vehicles built within the following VIN breakpoints:



You need to check with your dealer to see if yours qualifies.

[Buoy]

Thanks Ted!!
Yep, sounds like mine fits all the criteria. 2004, and a little over 41K miles.
I'll call the dealer this week.
Thanks again!

[99fever27]

It's the stepper motors in the gauges that go bad in these years. It's actually a easy fix if the dealer doesn't want to help you. I replaced all mine in the tahoe earlier this year, not because they went bad but just as a precaution. Plus I added the trans temp. gauge. You can have the dash out in under five minutes and solder a new stepper motor in pretty easily.

[inbetween]

It's the stepper motors in the gauges that go bad in these years. It's actually a easy fix if the dealer doesn't want to help you. I replaced all mine in the tahoe earlier this year, not because they went bad but just as a precaution. Plus I added the trans temp. gauge. You can have the dash out in under five minutes and solder a new stepper motor in pretty easily.

Post a link to the source for the motors. My out of warranty '04 Yukon could benefit from them.

[99fever27]

Post a link to the source for the motors. My out of warranty '04 Yukon could benefit from them.

http://cgi.ebay.com/ebaymotors/1-200...Q5fAccessories

And a write up for installing a tranny temp. guage but it applies for replacing the motors too......

http://z71tahoe-suburban.com/iboard/...=stepper+motor

[Sydwayz]

I think my Brother in Law has gone through 3 dash units on his 2003 Avalanche 1500. Neither of our 2002 Avalanche 2500s had a problem.

[Buoy]

My truck doesn't have a tach.
God knows what could be happening in there.

Yeah, I know what ya mean.
As long as it's there, I want it fixed.
Think about it, if you're tooling down the highway at 70, glance down and note the tach at 6K, there is a certain pucker factor that you are very soon going to have oil all over your windshield, and possibly a rod through the block.

[fund razor]

Yeah, I know what ya mean.
As long as it's there, I want it fixed.
Think about it, if you're tooling down the highway at 70, glance down and note the tach at 6K, there is a certain pucker factor that you are very soon going to have oil all over your windshield, and possibly a rod through the block.

No doubt, and once you are a boater.... you become a tach watcher. Oil pressure and temp too. It would have been a wtf?!? moment for sure. Like looking at your oil pressure and its 5. Or less.

[Bobcat]

yes and problems will compile , and the next thing you know it is an






avalanche




I am officially out of material

[Buoy]

No doubt, and once you are a boater.... you become a tach watcher. Oil pressure and temp too. It would have been a wtf?!? moment for sure. Like looking at your oil pressure and its 5. Or less.

Yeah, I think that's why it got to me so bad...
Boat related dementia or something...
Yep, I find myself checking all gauges every few minutes, must be ingrained in me.
When I saw 6K on the tach, I was looking to chop the throttles, and be ready to get back on it upon re-entry.
And also thinking that the new tires I was out testing needed more pitch

yes and problems will compile , and the next thing you know it is an






avalanche




I am officially out of material

Say goodnight Bobcat.

[Bobcat]

[smokin' joe]

My '03 Z71 speedo works sporadically. Other gauges are OK. Since mileage is beyond the General's warranty, I just use the tach to calculate speed. So far no tickets...

[Buoy]

Glad at least someone got a square deal from Govmint Motors

Thanks again for your "gift" to me Ted.
I'm sure it saved me a couple hundred bucks, and/or a few hours of searing and throwing tools
All fixed up and good now.

[Geronimo36]

I have a friend with a weird problem on his Avalance.....any help is appreciated!!!

Out of the clear blue the headlights will just shut off for no reason at all... If you open the hood and slam your fist down on the fuse box the lights will come back on... We've checked all fuses/relays and everything seems fine....

any suggestions?