I recently fixed an intermittent problem on an FNR5 transmission in a 2006 Mazda 3. The shop that brought it to me had been trying unsuccessfully for the past six weeks to fix it. When I called to inform them that it was fixed, they asked how I was able to fix in such a short time what they had not being able to do in weeks.
That question is what prompted me to write this article, not because I believe I’m in any way more intelligent than the average transmission diagnostician but because of the approach I used that allowed me to find the intermittent problem.
With the addition of parameter identification data (PID), we can combine data with our knowledge of the way a transmission is designed to work and use it as a form of X-ray that permits us to see inside the transmission, so to speak. Let us use the following example to illustrate this.