I haven't had the opportunity to take the new model course as yet, but I have taken a quick peak at the service manual for the '04 Ex.... Any DIYers that will be purchasing a 2004 Exploder can look forward to a new learning curve.
While the '04 doesn't look much different sitting in the driveway, there are many differences under the skin. Like it's predecessor, the '04 boasts 3 distinct computer networksGone is the Standard Corporate Protocol network (the one that the PCM dominated) in favour of the high speed CAN (Controller Area Network) protocol. The first thing that we'll see is that this network will likely render the AutoZone (et al) scanners useless. While a talented scanner may be able to access some of the other modules not totally dependant on the CAN, the functions of the PCM will be inaccessible.
A"full load" Ex will have one less module... down to 9 according to the manual. As far as I can see, all of the functions involved in the change have been swallowed up by the PCM, including cruise control and 4WD control (no more cruise actuator and no more 4WD module).... before I forget, there is no more throttle cable, either.
As far as the PCM itself is concerned, there is a laundry list of inputs and outputs but, for those with a basic understanding of their home PCs, there shouldn't be anything beyond basic comprehension. It will only be a matter of time before the popular parts houses have scan tools capable of confusing us.
I think that the step to the new network will be much smaller than the leap from carburettors to fuel injection. I will mention that having a set of manuals is going to be a bigger requirement than ever before. I'm reminded of a Windstar I worked on two or three months ago...... the left tailight, right and high-mount brake lights and one of the rear turn signals wouldn't work. This would be a work of art without the manual since the culprit was one blown fuse (that wouldn't recur with a rough road drive cycle)...... word to the wise... we are used to fuses controlling systems and not random lights. Last week.... a Ranger suffering multiple problems. A blown fuse to the GEM fixed the radio, the power windows and about 3 other problems (got that CRS disease... can't remember sh*t). But the power locks and horn still refused to work. After substantial time (and hopefully no flat rate chargeback), I found that the owner had dutifully checked all of his fuses..... well most of them, since he didn't realize there was a fuse panel right there where the door opens... and inadvertently reinstalled a fuse in the wrong location. Yep, we all know that the fuse for the 4WD module controls the horn and power locks..... well, at least we know it now.....go figure.
The best advice I can offer is to get a manual... get the best manual you can find (noticce I didn't say 'adequate' manual), read the section(s) on how the system operates.... without this knowledge we are hopeless.... read this section many times and don't gloss over any facts and you will be in good shape.
Most of you DIYers adapt to the times quite well...... just remember that now, more than ever before, attending to problems when they occur rather than waiting until they are unbearable, will provide their own rewards (most of them, monetary.... honest)....
-- Jim Warman snipped-for-privacy@telusplanet.net