Scan Master problem

xtremexnyc

Well-Known Member
OK here goes, when i power up my scanmaster 2.1 it blinks and then it reads 2.1, after that it turns off. I'm pretty sure i have the wiring correct positive to a 12 volt source and negative to a known good ground. Trigger wire is connected to the ALDL connection pin E. If anything i tried each connection in the ALDL port. If my Scanmaster is bad, is it worh to have it repaired? Whom can i call to fix the problem. How much would it cost?

Thanks for the help and advice.
 
it sounds like its not getting a signal from the ecm, when it doesnt see an ecm signal it will shut off.
maybe there is a bad connection to the aldl port from the ecm, or there might be an open in the wire from the port to the scanmaster.
 
I went thru the same thing on my Scanmaster about a year ago. The SM's are fairly picky about having good wiring connections. Mine would flake out and I could shuffle the wires around and it would work for a while....until it finally just quit.

I spent some time on a Saturday morning and reinstalled it using good splice connectors and soldering it up.....hasn't missed a beat since. Those 3M splice connectors are "cool" and easy to use, but they don't really make a good connection that will last.

Bob Bailey who is the original designer of the ScanMaster frequents this board and may have some insights, but I think you'll find that all you need to do is check your connections carefully...The ScanMaster is a very robust design.

Good Luck,
John
 
SilverSleeper and OKturbo thank you guys for your input. I will recheck my connections again. I know someone had a site with the exact pin outs on the ALDL connection but his site is down for some reason. I know this should be a simple connection but does anyone have a pic of the exact pin out of the ALDL connection just to be sure? I hope you guys are right as this will save me a whole lot of $.

Thank you for your help:)
 
Hi,

Got your e-mail, but thought I'd reply here.

The Scanmaster design has not changed since it was introduced.
It has been an extremely reliable device with very few problems.
For all the units I have received for repair, most have been fine.
About 2 years ago we switched processors to an improved version that
is less prone to trouble if the ground is flaky. But, like all modern electronic
gizmos, good grounds are essential.

Since your unit is powering up and displaying "2.1" your power and ground
connections are probably fine. So it would seem that the datastream is not
making it into the unit.

If the unit is receiving data, one of the decimal points (the one at the far right)
will be blinking while the unit displays "2.1".

Since the data is essentially "ground pulses" you can verify that
the Scanmaster can receive pulses by touching the data wire to
ground after the unit has gone to sleep. If you touch the data
wire to ground while the unit is sleeping the unit should go through
the "2.1" sequence again looking for data.

The data wire in the GN's is orange, I think. So look at the back side of the
ALDL connector for the orange wire and use that pin to connect to the Scanmaster.

I have seen several cases of defective ECM's, The engine runs fine but no data
comes out. What happens is the low speed fan relay or the TCC solenoid shorts out
and kills the quad chip in the ECM. Plug in another ECM and still no data
(because you killed that ECM too....) I have a small pile of ECM's that suffered this fate.

So, the above said, I'd be happy to check out and repair the Scanmaster for you. No charge.

But try the 'touch the data wire to ground' test as a first step.

Post your results here. If you want to send the unit to me for checkout
let me know, I'd be happy to help in any way I can.


Bob
 
Originally posted by TurboBob
Hi,

Got your e-mail, but thought I'd reply here.

The Scanmaster design has not changed since it was introduced.
It has been an extremely reliable device with very few problems.
For all the units I have received for repair, most have been fine.
About 2 years ago we switched processors to an improved version that
is less prone to trouble if the ground is flaky. But, like all modern electronic
gizmos, good grounds are essential.

Since your unit is powering up and displaying "2.1" your power and ground
connections are probably fine. So it would seem that the datastream is not
making it into the unit.

If the unit is receiving data, one of the decimal points (the one at the far right)
will be blinking while the unit displays "2.1".

Since the data is essentially "ground pulses" you can verify that
the Scanmaster can receive pulses by touching the data wire to
ground after the unit has gone to sleep. If you touch the data
wire to ground while the unit is sleeping the unit should go through
the "2.1" sequence again looking for data.

The data wire in the GN's is orange, I think. So look at the back side of the
ALDL connector for the orange wire and use that pin to connect to the Scanmaster.

I have seen several cases of defective ECM's, The engine runs fine but no data
comes out. What happens is the low speed fan relay or the TCC solenoid shorts out
and kills the quad chip in the ECM. Plug in another ECM and still no data
(because you killed that ECM too....) I have a small pile of ECM's that suffered this fate.

So, the above said, I'd be happy to check out and repair the Scanmaster for you. No charge.

But try the 'touch the data wire to ground' test as a first step.

Post your results here. If you want to send the unit to me for checkout
let me know, I'd be happy to help in any way I can.


Bob

Now this is a stand up kind of guy! You get 2 thumbs up!

Bob thank you for replying to my email. I will go ahead and do some more troubleshooting this evening. I will post my results and let you know if it works or not. If anything i'll try it on my friends car when he gets back(out of town), just to rule out that it is not the Scanmaster. Again i really appreciate all the help everyone has given me.

Thanks
 
Good News

I got the Scan Master to work correctly. Turbobob i did the ground test like you said and it did wake up the scanmaster. I ruled out the scanmaster was working fine. There was some corrosion on the ALDL connector. I cleaned it up with some fine sand paper. Put the data wire on and now it works correctly. I just want to thank all who helped out in this matter.
 
In front of your left knee under the dash, in front of the fuse box is a factory ground screw. Lay down and look up you can't miss it
 
Glad I found this. After changing to a BRF transmission (from the stupid KCF trans some po put in) my scanmaster stopped working. Did all these tests, and I have decided its the PCM. Now, my low speed fan was giving problems before, and I swapped the relays today and the high speed still works fine with the other relay. So it stands to reason, there is a problem with the tcc solenoid wiring. Anyone have any input before I toss another PCM on it?
 
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