Newsom09

Well I have a 96 4x4 tahoe and it's confused me so badly lately. First of all, my speedometer won't work, my ABS light is on, my service engine soon light is on and when I plug my code reader up to check the codes, the reader says NO LINK. As far as the speedometer and ABS light, I have done some research and found out that along with making the speedometer stop working, the Vehicle Speed Sensor sends signals to the ABS system and if it goes bad, it will cause the ABS light to come on. Well I traced the wires from where they plug into the sensor all the way to the PCM and coudn't find any bad wires or anything and I replaced the Vehicle Speed Sensor today and it didn't fix the speedometer and the ABS light is still on. And like I mentioned in the first of the thread, my service engine soon light is on and my code reader says NO LINK when I plug it up. So does anyone know if it is the PCM or if not, does anyone know anything else that it could be doing all this??

in2pro

Could be but have you tried a re-boot? disconnect the battery and short the disconnected terminals together, wait about 10 min and give it a go...
Make sure any aux batteries are disconnected prior to shorting cables together....

RacerX

if you didnt find any exposed wires in the entire harness the PCM may be bad. Take it out open it up and smell it for burn connections. they tend to have a rubbery smell. The PROM may be good but the circuit board may have fried.
check the ground wire as it goes from the PCM to the ground station.

Newsom09

When you mention the reboot and shorting the terminals together, are you talking about shorting the positive and negative cables together?? and when and if it resets, what all will it do as far as the SES and ABS lights, speedometer and obd2 plug??

in2pro

Yes to shorting them together after disconnecting all power sources, and it should clear out any codes, as for the function of the datalink connection who knows.. but it will at least give you a fresh place to start by clearing out any old data and anything that comes up new will need to be addressed...

Newsom09

Well today I put the cables together to reset the codes and when I put the battery back on and started my tahoe up, the SES light was off but it came right back on about 5 or 6 seconds after I started it. As far as taking the PCM apart and smelling for a burned smell, I did take it apart and I could smell a slight burned smell but nothing strong and nothing looked burned or black or anything on the circuit board as far as I could see.

EinST

Is it possibly a DLC power problem? Make sure pin 4 is ground and pin 16, battery voltage (from Aux Pwr fuse)?

kaylasparks7185

I had the same problem with my 2007 Chevy Trailblazer and it was one of the many relays was out I cannot remember which one but I would start there if I were you

SuniC77

I have a 2005 Chevy Trailblazer that I change the ignition in and then they said theft deterrent lock was bad now my steering wheel is back together but my car won't start lock went out change that now all the sudden the car won't start it says that I need to know if it's my ECM PCM or PC and wear one of these p.m. is there any way anybody is knows anything about this before I go and spend the rest of his money on a starter because now they say the starter is going out

SuniC77

QUOTE=Newsom09;175722]Well I have a 96 4x4 tahoe and it's confused me so badly lately. First of all, my speedometer won't work, my ABS light is on, my service engine soon light is on and when I plug my code reader up to check the codes, the reader says NO LINK. As far as the speedometer and ABS light, I have done some research and found out that along with making the speedometer stop working, the Vehicle Speed Sensor sends signals to the ABS system and if it goes bad, it will cause the ABS light to come on. Well I traced the wires from where they plug into the sensor all the way to the PCM and coudn't find any bad wires or anything and I replaced the Vehicle Speed Sensor today and it didn't fix the speedometer and the ABS light is still on. And like I mentioned in the first of the thread, my service engine soon light is on and my code reader says NO LINK when I plug it up. So does anyone know if it is the PCM or if not, does anyone know anything else that it could be doing all this??[/QUOTE]
I need to know if my bcm ecm pcm why can I not start my car I've replaced the ignition and theft deterrent lock I spent 400 dollars on n ignition please help