Huge win for car owners! All TSBs to be made public. The Center for Auto Safety just made the NHTSA (US Government) make public the full text of all TSBs from now on. They are the same organization that has petitioned the NHTSA & filed lawsuits to protect car owners over exploding gas tanks & other major safety issues. Whenever you drive in your car, you are safer thanks in part to a lot of work over the years by this small but very effective consumer advocacy group.

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really awful
Typical Repair Cost:
No data
Average Mileage:
85,000 miles
Total Complaints:
1 complaints

Most Common Solutions:

  1. not sure (1 reports)
2004 GMC C4500 electrical problems

electrical problem

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2004 GMC C4500 Owner Comments

problem #1

Feb 172007

(reported on)

C4500 6.6L

  • Manual transmission
  • 85,000 miles


I am a inter-provincially licensed mechanic in Canada. I am currently working on a 2004 GMC C4500 with fuel gauge defaulted to empty. The "TSB" for the breather tubes on filler necks did nothin' for the "PO" series code listed the "ECM". The "PO" code for the "fuel transfer pump insufficient flow", was diagnosed as-per diagnostic charts and the fuel sender units (which were rotted out) were both replaced, as was the wiring harness for both units, which is a complete harness for the rear of the vehicle. I then ran a "diagnostic chart" for the fuel gauge because now it is overfull !! With the end being a replaced instrument cluster and having to be "programmed" by an authorized dealer. The first dealer had to send ti to a different dealer because "we can't access the ECM because it is a medium/heavyduty truck. So when the truck was "programmed" It came back with a gauge reading EMPTY. One consolation, as I was working on this vehicle the oil pressure gauge went faulty and the voltmeter was consistently reading 18 to 19 volts , which it was only a maximum charge of 14.5 volts. The codes were cleared and the ECM came out of default and the gauge works again, for how long?? Every time the ECM stores a fault code for the fuel gauge circus it defaults the gauge to zero,, and if the "dealer" (which are overrated) reprogrammed the replaced module for completion of repair, why would they let the vehicle leave with fault codes and a fuel gauge on empty and not inform us , I had to clear codes myself as a final task. I am a very highly trained and up to date technician. I do alignments, electronics, emissions testing and diagnostics and all basic and complex repairs. The shop I work at has ten techs , more than some dealers, and strive to bring the highest of customer service and up to date tools, equipment and training for our techs. There is a very large problem now in our industry in NORTH AMERICA , the "OE" companies are not releasing repair information to the after market. This will not affect "dealers" to a great extent as the demand for repair is to great to be only serviced at the "dealers". Automobiles have advanced more in the last ten to fifteen years than since the first car rolled off Henry Fords "assembly line", and in the next ten years will advance even more. If the customer hopes to have there new fancy vehicles fixed "the right to repair" appeals should be taken notice of and let our industry grow and work together, not shrink and dissolve. I repair all brands of cars "BMW-AUDI-CHEVY-FORD-DODGE-VW-MAZDA, EVERYTHING!! I aspire and pride myself on being the best technician possible. Having information to repair my customers vehicles is needed.

- , Peterborough, Ontario, Canada

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