4th Gen H23A EGR code 12 and 4WS issues

**gumbs** · 02-08-2013 08:14 AM

I just bought a cheap 4th gen as a car to help a mate learn to drive (and as temporary wheels for my missus because she crashed hers) and within 30 minutes of leaving the guys place it started spitting fault codes at me.

I read the codes out and I'm getting code 12 from the check engine light and I initially got code 29 from the 4WS and then 74 after resetting it.

74 is handbreak on, and the handbreak light doesn't work so I'm hoping I just misread the code the first time and its just a loose connection on the handbreak switch. But if anyone else has other suggestions I'm all ears.

The EGR code is obviously less fun, it only comes up if you start the car warm (you can drive it from cold for an hour and it won't show up) but if you start the car warm it comes on at pretty much 5 minutes on the dot. The cruise control isn't working either so I'm thinking its probably a vacuum leak. I haven't been able to really find a "how to" guide on fault checking the EGR so this is my plan of attack, again if anyone has any suggestions or if I'm doing something stupid let me know.

1. Pull vacuum line upstream of EGR and suck on valve at idle to check if EGR is operating, car should stall.

2. Check that EGR vac lines are hooked up as per

3. Attach vac gauge inline with EGR bring revs to 3k manual excite EGR solenoid check vac on EGR line. Record number.
4. Move vac gauge to start of vac system bring revs upto 3k, record vac number.
5. Block vac hose downstream of gauge and rev to 3k again, record vac number.
6. If all 3 are similar I have a dead EGR sensor.
7. If the first two are significantly lower than the third I have a vac leak and should start working my way down the vac system until I find it.

Anything horribly wrong with that idea? The solenoid should be fine on 12v? Does anyone understand how the EGR vac solenoids work? Are they analogue or digital controlled with PWM? Google leads me to believe that they are digital and PWM controlled (which makes more sense as its more reliable) but I'm a little worried I may fry my solenoid with 14v direct from the battery.

**vtecprelly** · 02-08-2013 09:02 AM

Have you checked the EGR valve itself? they get ALOT of build up on them. Ive had one fail on me. swapped it out and it was all good from there. 4WS is never fun... Ive pulled the code for mine and it said the computer was failing. changed the computer and it worked fine for like a day. then same code

**gumbs** · 02-08-2013 10:02 AM

I haven't tried the EGR valve it self but the first test should tell me if its working or not. The last owner has removed it before and put the thing back on with some sort of blue sealant instead of a gasket

. So I'm hoping he's cleaned it, but if I can't find a vacuum leak I'll try cleaning it.

**vtecprelly** · 02-08-2013 02:14 PM

oh gawd why. good luck man!

**gumbs** · 03-08-2013 11:15 AM

So no vac leaks. The car stalls when manually applying vac to the EGR (as expected). The car also stalls when I manually activate the solenoid from the battery.

So that leaves me with 3 things.
The solenoid is only half working and is sticking when its partially opened using a PWM signal.
The sensors broken.
The EGR is blocked and isn't opening properly.

My next step is to take the EGR off clean it and any ports etc and then try and manually operate it with vacuum and see what signals it gives. I miss my 80s cars....