Mysterious miss - Page 2

***Power Hungry*** · #11 Tue, March 10th, 2009, 07:23 PM

Keep in mind that the programmer (whether it's Gryphon or Evolution) only accesses the PCM diagnostic codes. This mean that any codes in the ABS Controller, Transfer Case Controller, Body Module, Instrument Cluster, etc. are not read. 4x4 codes are often stored in the ABS Controller and therefore wouldn't be displayed.

As for misfire, those would be stored in the PCM for a number of Key Cycles and should be readily available using the "Read DTCs" function from the diagnostics menu.

Take care.

***Jackpine*** · #12 Tue, March 10th, 2009, 07:32 PM

Well heck! I learn something new each day. Thanks, Bill, I thought the PCM was the Great PooBah here and now you tell me it's only part of a committee! :o

- Jack

***Power Hungry*** · #13 Tue, March 10th, 2009, 08:20 PM

Actually Jack, that's a great way to put it. Your vehicle no longer has a "brain" but something more like a controlling committee or board of directors, if you will. All the modules interact with each other and share data on common nodes. In fact, late model vehicle can have as many as 25 active communications nodes in the vehicle. This makes things interesting when programming or doing diagnostics.

Take care.

***Jackpine*** · #14 Tue, March 10th, 2009, 08:43 PM

Quote:

Originally Posted by Power Hungry

Actually Jack, that's a great way to put it. Your vehicle no longer has a "brain" but something more like a controlling committee or board of directors, if you will. All the modules interact with each other and share data on common nodes. In fact, late model vehicle can have as many as 25 active communications nodes in the vehicle. This makes things interesting when programming or doing diagnostics.

Take care.

What a flippn' mess!

Hasn't anyone heard of the KISS principle?

One of my favorite SF authors, Robert A. Heinlein, once described a committee of ten as, "An organism with 20 legs and no brain". I've always felt that way about committees.

And now you tell me I have a committee in control of my truck?

- Jack

***88Racing*** · #15 Tue, March 10th, 2009, 10:38 PM

Thanx Bill and Jack for the info.

Get this if one part of the commitee is not communicating correctly during the shut off of the vehicle it can lead to a dead battery! Had a Ford Fusion that a lady kept having dead batteries in. Replaced the battery 3 times and the altenator 1 time, over a 3 week period.

Finally at the end of its rope. Had it hooked up to a computer for 2 days and 2 nights, while Ford monitored it. Finally a Ford engineer called and told us to look at the back of the radio and guess what it was a lose connection to the sirius module.

This is the way it was explained to us. The pcm is still the brain during start up and shut down. During shut down it contacts all the other modules to make sure they are ok. If one doesn't respond it wakes everyone else up and goes through the same process all over again. Thus the dead battery, because of the continuous cycling. And with an intermitent connection like the sirius module was, its like a needle in the haystack. Sometimes the connection was there and sometimes it wasn't. No problems every since then. We have also experienced the same problem with a gmc envoy except that one involved the transfer case.

Lars

***Power Hungry*** · #16 Tue, March 10th, 2009, 10:48 PM

Isn't troubleshooting fun???

***Jackpine*** · #17 Tue, March 10th, 2009, 11:09 PM

Good grief! Lars, I'm going to have sleepless nights thinking about what you just told us and wondering, if we're out in the boondocks, "Is my truck asleep, or, is it trying to get all the other committee members into a meeting?"

Thankfully, I have a little Honda 1KW generator I can use to start the damned thing if everything goes south.

- Jack

***88Racing*** · #18 Wed, March 11th, 2009, 07:31 AM

Isn't programming fun?

The problem is/was the "intermitent" sometimes there sometimes not. If a person thinks about the platform of which programming is based. It makes it easier to understand and why idiot lights don't come on. The thresholds for the conditions weren't met.

Did you know that something as simple as your tail light bulb is being monitored by the pcm and/or module. Via voltage and ohms.

Lars

***Jackpine*** · #19 Wed, March 11th, 2009, 09:29 AM

Quote:

Originally Posted by 88Racing

Isn't programming fun?

The problem is/was the "intermitent" sometimes there sometimes not. If a person thinks about the platform of which programming is based. It makes it easier to understand and why idiot lights don't come on. The thresholds for the conditions weren't met.

Did you know that something as simple as your tail light bulb is being monitored by the pcm and/or module. Via voltage and ohms.

Lars

I knew that a burned out 3rd brake light stops the cruise control from working (and I don't remember where I learned that). And a gent with the screen name SSCULLY, over on the f150online forum says if all brake lights are out, you won't be able to get the gearshift out of Park.

Lovely how engineering tries to protect us in every possible way.

- Jack

***88Racing*** · #20 Wed, March 11th, 2009, 10:56 AM

The brake light one has happen at the body shop they were replacing the box and needed the truck moved and it didn't.

What was the other one? I think on 96.5 to 04h, a head light goes out the dome light stays on.

Good old safety issues become head scratchers.

Lars

PS what ever happen to the cracked distributer cap or a bad plug wire?