We have a hand held reader which it occasionally connects to, but sometimes when it does connect it resets the clock on the radio. Any ideas on what could be wrong?
IT IS A COMPUTER. YOU WOULD HAVE TO REPLACE IT TO SEE IF THAT RESOLVES IT THEY RUN ABOUT $40.00 FROM A JUNK YARD. RECOMMEND YOU TAKE IT TO A DEALERSHIP AND HAVE THEM DO A DIAG ON IT. THEN YOU WILL KNOW. THEY ARE A PAIN WHEN THEY START GOING OUT. GOOD LUCK.
ECM may be Bad
how do we check that?
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Most connection issues ( no communication ) are the result of no power supply at the connector. Does your hand held unit light up when plugged in to the connector? You may have a blown fuse. Do all the power outlets ( Cigarrette lighter etc ) work? GM tends to put the OBD plug power on the same fuse as the power outlets. If one or more outlets are not working, check for a blown 20amp fuse in the underhood fuse/relay center
Testimonial: "yes the hand held will always light up it just does not always connect. and yes the power outlets all work and the fuse(15amp) which is under the hood is fine"
When you say doesn't connnect..... you are reffering to a no communication data display issue? Does your scan tool or any other scan tool come up with a no communication message?
it wont communicate with the state computer at all, and the hand held will always light up but does not always communicate with it
Have a look at the plug and make sure none of the pins are pushed back or spread apart too much. The class2 serial data should be the purple wire on the back of the plug that supplies info to the scan tool. If the scan tools are lighting up but not communicating I would suspect power and ground supplies to be good.You will have to determine whether the ECM is the problem (not common )or a wiring issue. You will have to check the purple wire from the plug to the ECM with an ohm meter for opens/high resistance. Not sure what connector this wire is located in at the Ecm. You can inspect the plugs at the ECM as well for signs of corrossion/water intrusion as well as for any damaged pins. Sometimes just disconnecting the plugs at the ECM and reconnecting them can correct this type of issue. (make sure key is off when doing this procedure). Also, wiggling the wire harness as it enters the vehicle at the firewall and in any other location you can wiggle it may help find/correct your problem. Hope this helps
we will check that out thanks
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