P0400 error code - NOT the EGR - removed and cleaned it all

[etaf]

I have a 93 Saab 150 BHP Engine and the engine light often stays on only intermittently when starting and the code is the gas recirculating error P0400 - I have a code reader , which also will read the engine running

I have removed and cleaned out the EGR valve (square onto the engine and ellipse onto the pipe ) and it was very full of carbon - so cleaned that OUT
I also made sure the valve was cleaned and used WD40 to make sure it open and closed freely

I also removed the solenoid and cleaned that with card cleaner and with WD40 - so the pin clicked in and out

fitted new gaskets

however the light still stays on - BUT ONLY when starting ( engine light never comes on while running ) and maybe only after 10 or more starts - if you dont wait for the check to finish it will come on more frequently
when the light is on it run fine, infact since cleaning out its running much better.

I have used the car and it runs fine on motorways at 70mph and also I tried using the revs 4500 in gears to see how it performed and its was great - also had someone follow me and no issue with smoke from the exhaust

resetting the code - it will now work for the next few days (about 10 starts)

the car runs really well
NO smoke out the exhaust
revs upto 4500 with no issues
pulls really well
been on a comple of 100 mile trips and it runs great

I have been on another forum when this first started , and advised that it maybe the ECU , which is under the front wheel panel
OR
It may be a sensor on the manigold

I have in the past had a steering lock warning come up - that has happened twice in the last 2 years 10,000 miles.

any advice welcome, as i do not have the funds to put in a garage and would like to get resolved myself if possible.
And certainly could not afford a new ECU - which i suspect would be in 4 figures

As MOT due in Sept , i don't want the light to come on when they start the car and fail

The Code reader I have will also provide some live information with the engine running

thanks

[fastcars_hardy]

It might be the wiring. I have had a few brake just behind the plug but this is rare. To be honest I would try a new egr. Do youhave any other codes. The eengine light is not a mot fail

[etaf]

Thanks for the reply ,

I meant to update the forum,

I ended up cleaning the Throttle Body, all the sensors
and eventually replaced the EGR valve and its now working all ok

I saw a MOT list and that from 2012 the engine light was now included in the MOT , not that it matters as its fixed now

Thanks again