1993 TransSport 3.800
Has somebody got the correct list of code definitions for this van?
I did a forum search to no avail. I did a google search to no avail.
My old girl has codes 17,18,26,and 56.
It starts right up and runs fine but a few miles down the road starts to limp.
I love this old thing. I am going to clean 'er up and go around with 'er again for awhile. [Reply]
17 Camshaft Position Sensor error
Is the CSP Sensor easy to get at?
18 Where is code 18?
26 What is QuadDriver Module A?
56 What is QuadDriver Module B? [Reply]
Quad driver faults tend to lead towards an ECM......
Basically, a Quad driver commands up to 4 different circuits......if the quad driver gets the wrong data from a circuit, it sets a quad code.....
Not easy to diagnose....proper testing, is you isolate each circuit the quad driver runs.....you activate the circuit by grounding it with an ampmeter....you observe the current for up to 10 minutes, and if current goes out of range, you found a problem circuit.....
For example, suppose one of the circuits controlled is a relay...lets say the coil of the relay shorts out and now current is high.......the quad driver detects this, shuts down the circuit, and sets the code.....this is labor intensive, and most techs would just swap out an ECM from another vehicle(must be the same number, and if the PROM is different, have to swap them also), and if it took care of the problem, then they would just order an ECM, with the latest PROM for it.....
Like I said, more often than not, it's the ECM.......but with this time and mileage on it, it could be the circuit, a component in the circuit, or a bad connection also.....like I said, not easy to diagnose..... [Reply]
It is behind the glove box, high on the firewall. Image
But all quad driver fails almost NEVER (in my case absolutely never) mean a fault of the drivers, but a fault of the elements or circuit controlled by the drivers. I never had to go to the ECM itself, excpt to its intermediate plug C111 Image www.avigex.ca/xport/c111.jpg www.avigex.ca/xport/c111b.jpg
on the engine side (firewall, above passenger wheel bowl) to take measurements by removing the plastic cover. C110 (same model) is also used as intermediate, near the passenger side headlight..but I never went to that one.
THe EGRvalve is the classic problem with DTC56, and purge canister valve with DTC26.
Some of DTC56 are related to transmisison control...but if all shifts are OK, then problem not transmission side.
To test EGR valve, pull plug from valve, D (from DTC55 page) is ground, A,B,C are the coils. I remember two coils are 25 ohms and one 12 ohms. It happens one of them is broken..infinite ohms. In one occasion the fail was with the plug contacts. [Reply]
LMP, I have to disagree....those late 80's and early 90's PCM's were notorious for failures.....If you were lucky, a "tap test" would verify it....
But seeing how this PCM is 25 years old, chances are in it's lifetime it has been replaced....in fact, I would not be surprise if the label on it states "Reman".....
And as I stated before, I agree with you, every circuit would have to be checked out on the quad drivers to diagnose which could be labor intensive.....could be something as simple as a connection....but finding it is like a needle in the haystack....
And you would need wiring diagrams, a good meter, and the expertise to do the tests......only thing that saves your butt is a visual inspection, that shows something obvious.... [Reply]
Originally Posted by LMP:
It is behind the glove box, high on the firewall. Image
But all quad driver fails almost NEVER (in my case absolutely never) mean a fault of the drivers, but a fault of the elements or circuit controlled by the drivers. I never had to go to the ECM itself, excpt to its intermediate plug C111 Image www.avigex.ca/xport/c111.jpg www.avigex.ca/xport/c111b.jpg
on the engine side (firewall, above passenger wheel bowl) to take measurements by removing the plastic cover. C110 (same model) is also used as intermediate, near the passenger side headlight..but I never went to that one.
THe EGRvalve is the classic problem with DTC56, and purge canister valve with DTC26.
Some of DTC56 are related to transmisison control...but if all shifts are OK, then problem not transmission side.
To test EGR valve, pull plug from valve, D (from DTC55 page) is ground, A,B,C are the coils. I remember two coils are 25 ohms and one 12 ohms. It happens one of them is broken..infinite ohms. In one occasion the fail was with the plug contacts.
I will run the ohm tests on the EGR, and on the connector as you say.
I will see if there is a good looking EGR valve at the 'pick yerself' wreckers, and a Purge Canister valve too.
Is the purge canister valve right at the canister or...? How do you test it?
I remember the gas tank isn't venting properly; it builds up a vacuum which is very apparent when you open the gas cap when low on fuel. Is that related to the purge can valve code 26?
Thanks for the picture and diagrams of the black plastic PCM intermediate connector on the wheel well? Do you use that to test the QDrivers? [Reply]
Originally Posted by Tech II:
LMP, I have to disagree....those late 80's and early 90's PCM's were notorious for failures.....If you were lucky, a "tap test" would verify it....
But seeing how this PCM is 25 years old, chances are in it's lifetime it has been replaced....in fact, I would not be surprise if the label on it states "Reman".....
And as I stated before, I agree with you, every circuit would have to be checked out on the quad drivers to diagnose which could be labor intensive.....could be something as simple as a connection....but finding it is like a needle in the haystack....
And you would need wiring diagrams, a good meter, and the expertise to do the tests......only thing that saves your butt is a visual inspection, that shows something obvious....
I am going to leave the actual PCM til last because of the cost of the thing but I will see if there is a unit at the pick yerself that I can use to swap test the codes. I had to change one out on a similar year Buick once.
I'll do a bit of connection testing in the haystack but hopefully I don't have to get into any of the QDriver testing proceedures. It sounds like a big job. Thanks for that! [Reply]
Originally Posted by LMP:
THe EGRvalve is the classic problem with DTC56, and purge canister valve with DTC26.
Some of DTC56 are related to transmisison control...but if all shifts are OK, then problem not transmission side.
To test EGR valve, pull plug from valve, D (from DTC55 page) is ground, A,B,C are the coils. I remember two coils are 25 ohms and one 12 ohms. It happens one of them is broken..infinite ohms. In one occasion the fail was with the plug contacts.
The closest resistance readings of the 3 coils that I could find was 50 ohms on two and 25ohms on one. Does that sounds feasible? I remember changing the EGR valve and solenoid cluster 5 or 6 years ago.
There is an ugly transmission shift that happened a few times times on the highway (I think I started a thread on it way back when). When using the passing gear in the mountains it would pound back into cruise quite vehemently! I am going to change the vacuum modulator valve on the side of the transmission to see if that eliminates that occurrence.
Is there a transmission control module, a TCM or something similar? [Reply]