Under certain conditions, some GM high-performance cars with manual transmissions force a 1st to 4th shift. Everybody but Nancy Pelosi and the EPA hate it. Here's step-by-step instruction on how to defeat it for $7.
It's called "Computer Aided Gear Selection" or CAGS — and it's a system which works by using a solenoid in the transmission to force the driver to shift from first to fourth when you're driving in a leisurely fashion in 1989-and-on GM vehicles using certain 6-speed transmissions. It's purpose is to improve gas mileage and avoid the "gas-guzzler" new car tax.
CAGS comes into play under the following conditions:
* you're in 1st gear (of course)
* you're at 35% throttle or less
* you're between 15 and 21 mph
* engine coolant temperature is greater than 171 F (77 C)
We've noticed this annoying but necessary evil which allows cars with monster power to avoid the dreaded gas-guzzler tax by squeaking out a few extra miles per gallon in late-model Corvettes, but also, most recently, in the Pontiac G8 GXP. Which is what got us thinking about how to get around this little bugger of a dilemma. Luckily, it's pretty easy to defeat. There are systems on the market which plug in and kill the skip-shift for around $20-$40, but if you're a cheapskate with a Corvette or CTS-V, we've just discovered a $7 hacked solution that'll work just as well.
The guys at CadillacFAQ hacked together a replacement quick-disconnect plug which replaces a part of the same with one loaded up with a resistor as jumper to fake the system into thinking the servo is still in the circuit. All it takes is a replacement plug bought from the local parts store (here a "Conduct Tite" male end connector part number 85307 - $2.99) the pins to load into that connector ( "Conduct Tite" inserts, part number 85317 - $2.99), a 2.2K ohm 0.5 watt resistor from Radio Shack which costs about $1, some solder, electrical tape and time. The hacksters here soldered both ends of the resistor into the pin inserts after crimping them on, then bent the resistor for insertion into the plug housing.
Here they just leave it bare and insert it into the connector leading to the transmission, leaving the servo unpowered, then they tape it all together with duct tape and call it good. We'd probably get a vacuum cap and stick it over the end, then seal it further with heat shrink wrap, but that's just us. In any case, for seven bucks you no longer have the annoyance of your transmission wrestling some amount of control from you. Now perhaps Krewson will grant the Pontiac G8 GXP that final star in the transmission department. [CadillacFAQ]