boatwreck

I purchased an Auto Tap OBDII diagnositc scanner to use on my 01 Mustang GT but can't get it to connect. I know the Ford protocol is J1850 PWM with metallic contacts on pins 2,4,5,10 & 16 but my Mustang actually has metallic contacts on pins 2,4,5,7,10 & 16. The scanner is made for use on Fords & works on Fords owned by our friends but not on the Mustang. Could it have something to do with pin 7?

BraMas

I have a really good OBDII/CAN scan tool that will not read my buddies 02 GT but it reads every other Mustang I have plugged it into (I've scanned everything in between 96 to 09 GT's with no problem but on his). But I also have a cheap OBDII reader and that works every time on his car. I have never figured out why

cliffyk

All Mustangs, 1999 to 2004 have pin 7 populated, it is the ISO 9141 protocol and is used to obtain communicate the GEM, RCM (restraints [air-bag] control module), and some ABS functionality. Ford's IDS (Integrated Diagnostic System) and other "pass-through" tools and software can "talk" to these modules.

It should also have pin 13, which is used to supply the programming voltage when flashing the PCM.

Check fuse #31 (10A) in the central junction box, it supplies +12V to pin 16--its only function so it can be blown with no symptoms until you try to connect a scan tool or programmer.

Also, make sure the terminals are all in good shape and not pushed in or otherwise damaged. I have seen them get damaged when ham-handed techs with well worn equipment get overly energetic...

boatwreck

Thanks for the info. Will check out the fuse & see what happens.

cliffyk

Check the voltage between pins 4 and 16 of the datalink connector, and also pins 5 and 16--you should get a reading equal to or near the battery voltage. Pin 4 is the chassis ground, pin 5 is the signal ground, I have seen some scan tools use use only one or the other as their "ground" connection.

If you have +12V between 4 & 16 and/or 5 & 16 then the scan tool should at least "light up".

You'll need an oscilloscope to check for active signals on 2 & 10 (the J1850 PWM + and - signals), and between pins 5 and 7 (the ISO 9141 signal).

boatwreck

Tool does light up & scan just won't lock onto a protocol. Guess I should also tell you I was wrong about the brand of scan tool - in case it makes a difference. Using MaxiDiag US703 by Autel which is a company that does not know the meaning of support!!

cliffyk

I have not before heard of that brand or tool. I have 3 or 4 Actron scanners (and 2 or 3 non-handheld DTC scan tools) I have acquired over the years and have yet to run in to a vehicle to which they would not connect...

jing10086