Hi, our 2004 1.5 ltr. Auto has just developed a PCM failure characterised by the enginewarning light coming on. The Mazda mechanic says it might need replacing which in Australia is a stupid $2000 plus fitting. So pls help with advice.......

We had to replace the battery about 4 mths ago, the technician poured hot water onto the vacant battery tray to clear off the congealed battery gunk before installingthe new battrey. If the PCM is below this tray, could this have affected it ? Is the PCM protected from external moisture ?

Otherwise, what cables could we check for corrosion or looseness ? We have done about 29000 km.

Thks in advance, KP

 

PCM should be protected permanently from all normal environmental elements, pouring water over the tray should not hurt it. What MIGHT hurt it (dont hold me to it) is if there was acid leaking out and getting on the PCM if its under the tray. What trouble codes are you getting? Does the car run ok still? I would look at the cables anyway on a car this old, there are bound to be a few loose ones and it cant hurt to tighten them.