There are basically three different styles of speed sensors a transmission diagnostician has to deal with: a reed switch, an AC generator (pulse generator) and a Hall-effect sensor.
With a basic understanding of TAPS, the Transmission Adaptive Pressure System, covered in last month’s article, we will now try to tap into the Steady State Adapt System and what its data can tell us. Not all scan tools provide steady-state data, but I’m convinced that this information is a real help in diagnosing problems in the later GM units. Data for the examples I used in these articles was recorded on either my GM Tech2 or my Mastertech. All the units in the examples shown below are 4T65-Es.
The cliché “What you don’t know can’t hurt you” is way out of date. The single most-important commodity in the world we operate in is knowledge. Information – and that means good, factual information – is the only thing that stands between us and expensive failures. Our quest for information will include a good working knowledge of the operation of the complex systems that comprise the modern motor vehicle and their relation to one another, feedback from the customer to fully understand their problem and the results they want you to achieve, and a thorough and complete observation of the vehicle you are working on.
1998 to 2000 Kia Sportage and Sephia have the idle-air-control valve and the throttle-position sensor relatively close to each other. Figures 1 and 2 show the setup in the Sephia, which is similar to that in the Sportage.
Differences Between GM and Volvo Applications
The 4T65-E transmission is used both in General Motors vehicles beginning in 1997 and in Volvo 80 series starting in 1999. There are several major differences between these units that can cause some problems with parts interchangeability.
Every now and then we need to take a fresh look at how we are handling our businesses with respect to our customers, employees and suppliers. Are we giving them the respect and attention they deserve?