When the PCM commands the EGR valve to open to check its operation, it isn’t allowing enough time for the valve to respond. The real problem is the OBD II programming in the PCM.
#EBAY GM TECH 2 CODE#
Cleaning or replacing the EGR valve and clearing the code does not fix the vehicle because the code usually returns.
Changing the fuel enrichment curve, spark timing or some emissions control function slightly may be necessary to eliminate a hesitation, spark knock or other condition that develops over time.įor example, on certain GM vehicles the Check Engine light comes on and sets a code P1406 that indicates a fault in the position of the exhaust gas recirculation (EGR) valve. What works fine in a brand new car many not work so great after 50,000 or 100,000 miles of real-world driving. This philosophy of “build it now and fix it later” creates a lot of unnecessary recalls, but at least it gives technicians a way to fix factory mistakes without having to replace any parts.Ī reflash may also be required if the factory settings for the OBD II self-diagnostics turn out to be overly sensitive – especially after a few years of operation. Fortunately, it is not that bad yet with automotive PCMs, but it has become a crutch for automakers who rush products to market that aren’t quite ready.
#EBAY GM TECH 2 WINDOWS#
Every time Bill Gates rushes yet another version of Windows to market to perpetuate the Microsoft revenue stream, it always turns out to have bugs and security holes that were somehow missed but must be fixed by downloading and installing the latest Windows “service pack.” It’s a never-ending cycle of upgrades and patches. PCMs may need to be reprogrammed for several reasons. This allows changes and upgrades to be made as needed.
Today, virtually all PCMs have reprogramming capabilities as do many other onboard control modules (ABS, air bags, climate control, body controller, etc.). Ford and Chrysler were also doing the same thing as OBD II arrived on all cars and light trucks in model year 1996. By 1995, most GM models had the flash reprogrammable PCMs. It is all done digitally with the proper access codes and input data.įollowing the Geo Storm, GM began phasing in PCMs with flash reprogrammable chips in a variety of cars and trucks. PCMs built with EEPROM chips can be reprogrammed in a matter of minutes without having to remove the PCM or replace a single chip.
#EBAY GM TECH 2 MANUAL#
The General Motors PROM Identification manual that OTC used to provide with their Monitor scan tool and Pathfinder software contained more than 362 pages of GM PROM numbers!Įnter the flash reprogrammable EEPROM (Electronically Erasable Program Read Only Memory) chip. We are talking thousands of different PROMS. Every field fix or recall for an emissions or driveability problem created more part numbers to keep track of. Performance enthusiasts also liked replaceable PROMs because the chip could be replaced with one that provided more spark advance, fuel enrichment, a higher rev limit, etc., to squeeze more power out of the engine.īut replaceable PROMS had a serious drawback: there were too many of them! Every model year and every running change meant another PROM had to be created. It also meant that if a bug was later discovered in the original factory programming, it could be corrected in the field by simply replacing the original PROM with an updated corrected PROM (a tactic GM has successfully used over the years to fix many factory flaws). A replaceable PROM chip also meant the PCM could be “retuned” if necessary to correct certain kinds of emissions or driveability problems. GM pioneered the replaceable PROM chip as a way of programming PCMs to fit a wide range of GM makes and models. Previously, Program Read Only Memory (PROM) chips held all of the PCMs vital calibration information and operating instructions.
The first such application was the 1990 Geo Storm. How to: American vehicles (GM Ford Chrysler) PCM flash reprogramming tutorial in detail for newbies.įlash reprogrammable PCMs have been ussed in vehicles since the 1990s.
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