Hyundai Repair: re: speed sensor, speed signal, abs computer

Question
I replaced both input and output sensors, the front right abs wheel sensor and the one for the speedometer.  Cleared the codes with a scanner and still get p0500 after a bit of driving.  The computer that was replaced looks like the main one.  I see the airbag one- the one with the yellow harness and one on top of it that says remanufactured computer on it.  I don't see the word hyundai on it anywhere.  Hell, the computer wasn't even mounted right.  The nuts that hold it down were missing.  How much is one of these?  You think this might be the problem?  Thanks.


Answer
The air bag computer has nothing to do with the P0500 problem.  There are only three possibilities for what's causing this problem:

1.  The *ABS* computer is not sending the vehicle speed signal to the ECM.

2.  The wire between the ABS computer and ECM for this purpose is either open or shorted to ground.

3.  The ECM is defective, causing it to not read the vehicle speed signal sent from the ABS module.


The air bag computer could very well be causing the problem with your air bag lamp.  If it's not mounted properly, it could cause the air bags to deploy without warning.  I suspect the vehicle was involved in a collision deploying the air bags and was not repaired properly.  You should have the air bag problem diagnosed immediately.