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In my recent years, I've undertaken some more component level repairs and circuit board stuff. I had replaced my CPU#2 for click click no start about 5 years ago but kept the bad part. Today, I opened it up and here's what I found.
C3 circled in red at the top right has clearly leaked and become unserviceable. Following the yellow trace from this cap, this is the power input to the CPU#2 Microcomputer [no power to the computer no security system]. Additionally, It has leaked corrosive electrolytic fluid around the trace areas of transistor Q8 [basically the "relay"] for the security relay output that goes to pin 2D circled in red on the left.
I removed the components with my Hakko FR301 and cleaned the board with IPA. No damage to traces which is good. I tested the 3 capacitors on my ESR meter.
C3 220uf 16v cap was undoubtedly and horrendously bad at 103ohms with a limit of 0.33ohms.
C2 47uf 16c cap was barely out of tolerance at 1.73ohms with a limit of 1.6ohms.
C1 10uf 16v cap was bad as it read OL and couldn't produce a reading.
And here is the board with components reinstalled and capacitors replaced. Does it work? I don't know yet. If I find sometime later I'll try to install it and see if my click click start is fixed.
While it's good you have fixed it, I doubt that will fix the click click start. If you get NO click that could be the security relay.
The typical problem (and the one I had) was low voltage to the starter "small" terminal. The CPU just operates the security system relay, that is the only involvement.
Starter booster fixed my problem about 10 years ago and still going strong.
While it's good you have fixed it, I doubt that will fix the click click start. If you get NO click that could be the security relay.
The typical problem (and the one I had) was low voltage to the starter "small" terminal. The CPU just operates the security system relay, that is the only involvement.
Starter booster fixed my problem about 10 years ago and still going strong.
Dale
Hey Dale,
When I was originally troubleshooting the issue, I started with changing the security relay and the click click no start recurred. Then I added a starter booster from Banzai Racing and my issue was still recurring. Once I ordered a new CPU2 from Mazda and installed it, I haven’t had the issue since.
A faulty CPU2 is definitely the root of the click, click, start issue. This has been well established from years ago in the main thread detailing all the different fixes, causes, etc. Most can usually just jump the Security Relay to remedy the problem. But that circuitry runs through the CPU2 unit so eventually other issues related to the security alarm feature(s) will find a way into one's lexicon.
For me, in add'n to the occasional no start issue, it was the occasional scenario of me locking/unlocking the car door, resulting in my horn continuously honking due to a perceived security breach; plus, other related alarm oddities. I ultimately chose to replace my CPU2 w a new one from Mazda, and haven't looked back since.
It set me back around $250 I think. Obviously, using a paper clip to jump the relay is a more practical solution for many, and I could hardly argue w that reasoning. But I wanted peace of mind so I was willing to get a brand new one. This was about a decade ago so I'm wondering if these are even available nowadays. I'll have my FD for around 5 yrs max before finally letting it go so I'm hopeful my current CPU2 continues to perform as-is before suffering it's eventual leaky fate.
The nice thing about potentially refurbishing the CPU2 is that it can be easily swapped for a bad or existing one to test it out. Will be a good little side gig for the entrepreneur individual that becomes pretty efficient at repairing these. Who knows, that person might also be pretty good at refurbishing leaky ABS units!
12-30-23, 03:33 PM
