Rupert6

Hi, I’ve had my S2000 since new, with only 12000 miles on the clock, it’s close to mint condition, there has never been a problem with it until now. The ECU brings up an engine warning light on the dash and it goes into limp mode. Local garages as well as the main dealer are not able to fix it, Honda UK have also said there is nothing they can do. I have spoken to firms that deal with ECUs but all the ones I have contacted are unable to do anything with this particular Honda one. I purchased a secondhand unit which I put in the car, no engine light, great! But I am unable to turn off the immobilizer. Can anyone help with advice or a firm that might be able to correct the old or the replacement unit.
Many thanks
Rupert

engifineer

This is odd. ECU's RARELY actually go out. We have a shop in my family and my father said he has probably seen 10 or less ECU's actually be the issue in his career. Most of which were in the early days of cars having ECU's

What was the code that was set? Why did they say they could not help? This just seems odd.

Since you have not driven it you do not know yet if the new ECU fixed anything. A condition has to be set for some amount of time before the light is turned on. So there is a chance it will just come on again once you get it going.

Rupert6

The local garage told me the code was “0042”, they didn’t know if that was ECU or one of four sensors on the exhaust and recommended it went to a main dealer. So I had taken on a low loader to Stratstones Honda, Chesterfield. Initially they said there diagnostic machine wouldn’t talk to the car, two days later they had more success and that the ECU was at fault but they were unable to do anything further. They asked me to take the car away, I tried but the car was not drivable, I returned, they took the car back in, five minutes later I had it back the had somehow cleared the error code, with no engine warning light, it drove perfectly, I returned home. When starting the engine again same problems returned.
I appreciate your thoughts.

engifineer

Well that is an O2 sensor code related to the heater circuit on a heated O2 sensor. Odd that it would go into limp mode from just this code. Makes me wonder if they told you all the codes or just the first one they saw. A code reader is super cheap and worth having around. Would be nice to know what the full list of DTC's are to see where to go next.

If the shop just gave up like that, then better to not go back there. Even if it were the ECU, they should just replace the ECU! Them not being able to communicate with the ECU at some point is concerning, but hard to know if that was error on their part or an issue with the ECU itself.