To Flash or Not to Flash - Transmission Digest

To Flash or Not to Flash

At this point, everyone is familiar with the fact that most 1996 and later GM vehicles are equipped with computers that must be programmed (flashed) in order for the vehicle to operate properly. What some technicians may not be familiar with is the fact that earlier GM vehicles were equipped with PCMs that are also flashable. As a matter of fact, you could have a GM vehicle as early as the 1993 model year that is equipped with a flashable PCM. This is mostly because GM was the pioneer in developing the EEPROM and the programmable process.

To Flash or Not to Flash

Shift Pointers

Author: Pete Luban, ATSG Technical Supervisor

Shift Pointers

  • Author: Pete Luban, ATSG Technical Supervisor

At this point, everyone is familiar with the fact that most 1996 and later GM vehicles are equipped with computers that must be programmed (flashed) in order for the vehicle to operate properly.

What some technicians may not be familiar with is the fact that earlier GM vehicles were equipped with PCMs that are also flashable. As a matter of fact, you could have a GM vehicle as early as the 1993 model year that is equipped with a flashable PCM. This is mostly because GM was the pioneer in developing the EEPROM and the programmable process.

I’m sure most of you have experienced the following course of events: You get to the place in your diagnostic procedure where you have determined that this vehicle needs a computer. Let’s say this is a 1994 Cadillac Brougham with a 4L60-E transmission and a 5.7-liter engine.

You trot down to the local GM dealer and buy a new or remanufactured computer. You know there is a core charge on the original computer from your phone conversation with the dealer parts person when you checked on price and availability.

So to avoid paying the core charge, you take the original computer with you and leave it with the parts person.

You now return to the shop and plug your newly acquired computer in, and guess what – the car cranks but will not start. So maybe you call the dealer parts person or your tech service and you’re told that the computer must be programmed in order for this vehicle to even start, much less operate properly.

Sooooo, now you have a decision to make: Do you run down to the dealer and get the original computer back, plug it in and drive the vehicle to the dealer, assuming it is drivable? Do you tow the vehicle to the dealer in its present condition and let the dealer technician have his way with it and pay the labor charge. Do you have someone in your area who has what it takes to flash this computer and ask them for a favor? Or do you borrow this equipment and give it a shot yourself, realizing that if you are unfamiliar with the reflash process you could conceivably toast the computer you just bought? What a pain in the neck.

It would be nice to know going in that you’re working on a vehicle that is equipped with a programmable computer. Check out the charts in figures 1, 2 and 3 that indicate which 1993-1995 vehicles are equipped with programmable computers. The chart in Figure 4 lists the cars and trucks represented by each body code.

One final note: Not all 1996 and later vehicles are equipped with programmable computers. Vehicles that do not have programmable computers include medium-duty trucks like the GMC Tiltmaster with the Electromatic or Aisin Seiki transmissions, Cadillac Catera with the 4L30-E transmission, and GEO models.

You May Also Like

Sherlock Holmes Approach to an AB60 No-Move Situation

The effectiveness in diagnosing automatic transmission malfunctions is an art form. Although there are similarities among the wide varieties of transmissions on the road, each transmission has its own peculiarities. Aside from having mechanical, hydraulic, and electrical hardware systems to contend with, software/programming issues and various vehicle platforms make diagnostics much more difficult.  Using scopes provides

ab60

The effectiveness in diagnosing automatic transmission malfunctions is an art form. Although there are similarities among the wide varieties of transmissions on the road, each transmission has its own peculiarities. Aside from having mechanical, hydraulic, and electrical hardware systems to contend with, software/programming issues and various vehicle platforms make diagnostics much more difficult. 

GM 6T40 Pump Identification Guide

The 6T40 was introduced in 2008 for General Motors front-wheel-drive cars in the Chevrolet Malibu and has gone through several changes throughout its three generations, specifically in the pump area. The 6T40 is closely related to the more lightweight 6T30 and the heavier duty 6T45 and 6T50. Generation one started phasing out during the 2012

Seeing the Forest AND the Trees

They say that the proverbial phrase “I couldn’t see the forest for the trees” means that a person or organization cannot see the big picture because it focuses too much on the details. Related Articles – 4L60E Harsh 1-2 Shift – TASC Force Tips: Diagnosing 8L45 & 8L90 Shift Complaints – TASC Force Tips: Hydraulics

The Manifold Pipeway

The Honda six-speed transmission has been on the bench of many specialty shops for one reason or another (figure 1). But, for those of you who have yet to lay your hands on one, mounted on the upper side of the unit is one of the largest, if not the largest solenoid and pressure switch

8L90 Vacuum Testing

Below are the diagrams for vacuum testing GM 8L90 transmissions. Note: OE valves are shown in rest position and should be tested in rest position unless otherwise indicated. Test locations are pointed to with an arrow. Springs are not shown for visual clarity. A low vacuum reading indicates wear. For specific vacuum test information, refer

Other Posts

Shift Pointers: What to do when the 62TE TRS tab breaks

How frustrating it is when on a hot summer day, as you go to open a nice cold can of your drink of choice, and the tab breaks off? You are outside, away from any tools to remedy the problem quickly. It now requires a MacGyver mentality looking around at the resources available to get

Shift Pointers: Failures caused by incorrect tire sizes

For years ATSG has produced a wide range of issues related to improper tire sizes on vehicles. Even under-inflated tires have been known to cause issues. Problems such as premature failure with an active 4WD transfer case will occur with incorrect tire sizes. Related Articles – 10L80 and 10R80 pump gear differences – Top 20

Shift-Pointers-Jan-Figure-1-1400
Shift Pointers: Focused DTCs

On occasions when a vehicle’s computer system detects an error, it can set an array of diagnostic trouble codes. The variety and quantity of them require the ability to diagnose diagnostic codes, so it’s nice when codes set that point directly to the problem.  Related Articles – Going the extra mile: Proving your transmission repair suspicions

Shift pointers: High-mileage transmissions and the aches and pains of age

Among the most common four speed-transmissions keeping shops busy today are the Ford 4R70E/W, the GM 4L60-E and the GM 4L80-E. In most cases, this typically equates to working on high-mileage vehicles. Aches and pains come with age and/or high mileage. In fact, when we see a person who looks beat and tattered, some may

Shift-Pointers-November