Having problems with your 2002 Mazda 626 ?
CEL flashes(Code P0421), High pitch squealing @ start up, & Horn blows for no reason
\015 The car has around 108,000 miles. The CEL flashes on & off. It comes on in the morning and by the evening it goes off. The CEL may stay on one day and the next day it may not come on at all. The car also makes a high pitched squealing sound when starting the engine. And when the car is off, parked, and doors are locked the horn will just begin to blow for no reason. This happens at random times without any warning.\015\012\015\012Within the past month I have had a new PCV valve installed, transmission fluid flush, fuel system tune up, complete diagnostic check/scan, new spark plugs, ignition wire set, valve cover casket, and an air induction cleaning service. These services were done by Firestone & Precision Tune.\015\012\015\012Please help. I don't know what else to do. I can't afford to keep getting diagnostic scans and not get the problem fixed. I have been to the Mazda dealership in my area but their customer service was terrible & the rep didn't seem to listen to me or let me explain the problems. He just gave me the "you will have to get a complete diagnostic scan/service" line. "And that will cost you around $165.\015\012\015\012My car is paid for & I really do not want to purchase another vehicle. What can I do? Can my problems be fixed?\015
Diagnostic check is necessary as you have replaced many parts still not got your problem solved so to confirm your problem and come to some conclusion the check up is very much necessary.and what problem you r getting can be caused due to multiple reasons but it can be fixed for sure that i can tell you.diagnostic check will lead you towards the proper directions.
Sounds like your o2 sensor or catalytic converter. I would change out both. If you still need any help let me know. Please take a moment to accept and rate my solution accordingly. If you need further explanation I can provide that as well.
Repair Help & Product Troubleshooting for 2002 Mazda 626
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