DIY Honda ECU Repairs- P30 P08 P27

[E-Tech]

my problem now on ecu,..i change all capacitor,and then connect to car.
first time start the car, it running. but when i want start it in the morning, the car still same problem,
fuel pump not prime and car can't start. after thinking and research the problem.
i detect my ecu need in warm condition,(i test twice using iron warm the ecu board).
fuel pump prime as usually and car can start. do you think what's the problem on my board? i need change which component?
thanks e-tech

Pls send me a good picture. Like to see your repair job.
Tq

 

[woodardhsd]

I just came across this thread, great info here.

I have a question about my P28-A02 ecu. I have 93 civic, and the original ECU died 3 years ago. I picked this ECU from a local salvage yard. It's worked great for 3 years now, but just recently I'm having the same symptoms the last time my ECU died. There are no codes, no CEL, the car just dies and will not restart. After a minute or two, it will start, and remain fine for a few days. This happens randomly. I read here about the capacitors that often leak, so I pulled out my ECU and opened it up. the caps seem fine (to me) but I did notice a solder joint that seems burnt at one of the transistors. Here are a couple of pics of the burnt area, both front and back. Could this be causing my problem?

 

[levin818]

Burn mark usually seen on pin Collector (center pin). Your power TR looks Ok.

 

[E-Tech]

Levin is right...

 

[Diode210]

What ECUs can i take these components for IC17 (TA8903sn), QM1,2,3 and Caps from to fix my P28 ECU? Do all the Honda ECUs use the same components US or JDM? if not which ECUs should i be looking for to get those components from?

 

[levin818]

What ECUs can i take these components for IC17 (TA8903sn), QM1,2,3 and Caps from to fix my P28 ECU? Do all the Honda ECUs use the same components US or JDM? if not which ECUs should i be looking for to get those components from?

P27, P29, P30 or try similar year make Honda ECU.
As for Caps, please DO NOT re-use the old Cap. Always use NEW caps.

 

[levin818]

By the way, IC17 & QM1/2/3 are tough and hard to failed, unless its due to mishandling.
Through out my previous experience, i seldom replace those items (less than 1 out of 20 unit).

 

[syai]

Hi..sifus
my engine is B16A (auto) now running on P08 ecu.. ecu rechipped by previous owner. few months ago the CEL won't turn off for few times. but the car run ok

now.. the the engine is difficult to start. i have to push the pedal to make it start. when i push the pedal, the CEL will turn on and the engine will start as usual. and CEL wont turn off while running

have try changing the ecu with my fren and the problem settle

put back my p08... the problem happen again.

please.. help me. NO CODE DETECTED.

now the car just park at home. dont hv gut to drive.

 

[E-Tech]

Hi..sifus
my engine is B16A (auto) now running on P08 ecu.. ecu rechipped by previous owner. few months ago the CEL won't turn off for few times. but the car run ok

now.. the the engine is difficult to start. i have to push the pedal to make it start. when i push the pedal, the CEL will turn on and the engine will start as usual. and CEL wont turn off while running

have try changing the ecu with my fren and the problem settle

put back my p08... the problem happen again.

please.. help me. NO CODE DETECTED.

now the car just park at home. dont hv gut to drive.

Hi...
How's the inside of the ecu?
The caps ok or leaking like bury marks on the board?

So what help you want?
All informations has been posted, pls read thru'.

If you want someone to repair it, can also
be arranged at your choice (Penang, KL or
Johor).

Tq

 

[_firecracker]

Code 4 CKP sensor. Car is good, tested with known good ECU

Q31 was burnt out due to harness being plugged up incorrectly. Replaced with D2178 transistor. Now getting code 4 once car is cranked

 

[E-Tech]

Trace from connector B15 to the related cap and change it.
As I know Q31 no relations to code4.

 

[_firecracker]

Trace from connector B15 to the related cap and change it.
As I know Q31 no relations to code4.

It is connected to a the spot D1 which is blank, the lead goes from there up one space to C4, is this correct?

 

[levin818]

I can see your 33/35 and 220/35 are leaking. Suggest you replace all the E-Cap before you run the test again.
2SD2178 has too low hFE and it cant replace 2SD1780. Try get a 60V 2A Darlington TR instead.

 

[_firecracker]

I replaced all the caps, same issue. Do you know where I can get that transistor from?

 

[levin818]

Try google:
2SD1866
2SD2138
2SD2139
2SD2573

 

[Coupe-r]

I have a JDM P08 factory manual ecu.

Socketed by someone else and ran in customers car fine for a few months. Then random CEL's started when driving which bought up codes that didn't exist.

I then resoldered the socket and latch plus checked over everything. Main cap has been replaced.

ECU Passes on my moates engine Sim and primed the fuel pump, hits vtec, NO CEL.

Put ECU in the car and it primes the fuel pump but SOLID CEL. Car starts and runs in limp mode.

I removed J1 and put ecu back to stock. Primes fuel pump and SOLID CEL STILL!
When key turns on, fuel relay primes and CEL comes on. Relay clicks off and CEL remains on SOLID (like there is a chipping issue but J1 is removed now)

What inside the ecu can cause this? visually everything looks ok.

 

[E-Tech]

Remove the socket and and reconfirm all
the tracks to the main processor.
Suspect damaged somewhere...

 

[Coupe-r]

But so strange it passes on the moates engine sim??

I'll try this weekend :)

 

[Coupe-r]

Hi there, while I still need to check my broken P08.
I now have a P30 that mostly doesn't prime the fuel pump or has a HUGE delay in priming the fuel pump.

Once I get it to prime once it will prime every time after that.
If I unplug the engine sim for a while and retest the ecu, it's very slow to prime again.

P30 JDM ECU with a replaced C14 and a couple of burnt traces that are repaired.
Also replaced one other cap.
a 10v 47uf cap looks like it could do with replacing though.

Honda ecu fuel prime issues - YouTube

 

[Coupe-r]

I fixed the issue above by replacing the IC 17 Toshiba power IC.
I actually took one from a OBD1 P72 auto ECU (same part number but different IC location)

I also replaced the 10v 47uf cap that goes directly to this IC as it had signs of leaking.

Not sure if the dodgy caps cause these parts to fail, or start to fail as in my video.

ECU is perfect now

****EDIT: CUSTOMER NOW SAYS IT'S NOT PRIMING THE FUEL PUMP.***

Either the customers car is causing an issue or the moates tester does not pick up the issue (more likely a I have found a few times ECU's pass on the tester and fail on the car)
The best test appears to be putting it in an actual car still.

****EDIT 2: CUSTOMER SAYS IT WAS HIS CAR AND THE ECU IS FINE

 

[levin818]

IC17 will get fail when the leaking electrolite from the cap has folded its pin and cause unnecessary electrical conduction.

 

[_firecracker]

So while attempting to repair my ECU I broke the solder pad off the bottom side of negative side of the main board at C14 (the main 35v 220uf cap). The top solder pad of the ECU is still intact just the bottom pulled off.

I realize it seems to be a main ground but running a lead from the capacitor negative to ECU negative does not repair the ECU. I just get solid CEL, no fuel prime or anything, the ECU primed fuel before this.

The question is, where does this solder pad go to? where should I just a wire from the negative side of cap to the ECU?

 

[E-Tech]

So while attempting to repair my ECU I broke the solder pad off the bottom side of negative side of the main board at C14 (the main 35v 220uf cap). The top solder pad of the ECU is still intact just the bottom pulled off.

I realize it seems to be a main ground but running a lead from the capacitor negative to ECU negative does not repair the ECU. I just get solid CEL, no fuel prime or anything, the ECU primed fuel before this.

The question is, where does this solder pad go to? where should I just a wire from the negative side of cap to the ECU?

Which ecu? Wanna show me a pix?

 

[Extreme_events]

Hi
I have a P08 that wont start. No codes,
Cel comes on then goes off as usual and main relay clicks and pump primes as I have a fuel pressure guage. Engine cranks but does not start. Had to borrow a P30 chipped. Any suggestions? Board looks good. Pic attached. Any help will be appreciated ! Thanks

 

[Extreme_events]

UPDATE: changed Q25 and Q26. Car started but idles a bit low and rough. Will do more checks tomorrow. Any ideas in the interim?