Smo_GSR

Hi guys,

I drove home my new V4 STi home yesterday and all was well for a good 40 odd miles until I gave it a bit of right foot to pass someone on the motorway. When I did so I noticed the check engine light came on. I pulled over and did a diagnostic showing Error Code 33.

The car is now in limp mode but otherwise runs without an issue.

Can anybody shed some light on this please?

Thanks!

Splitpin

Is your speedometer still working?

If it isn't then either the speed sensor has failed or (more likely on an imported JDM car) the speed delimiter/converter has broken or one of its connections has gone dodgy.

If the speedometer is still working, is it reading properly/accurately/as you expect?

Smo_GSR

Hello mate, thanks for the reply. My fault for not being more specific, it's my first STi so please forgive my ignorance!

The car is a fresh import and still reading in KM's - the reading is accurate. I pulled out the clocks and it does appear that something has been spliced in, however as I'm new to these cars it could be OE.

Thanks.

Splitpin

Hmmm. So, if we look at what we know here, there aren't too many possible explanations for what you're experiencing:

If your speedometer is working, apparently reliably, the speed sensor in the gearbox is clearly not faulty.

If your ECU is throwing code 33, it clearly *thinks* the sensor is faulty. This points to the fault being in the connection between the speed sensor and the ECU.

I'll ask the obvious question just so's we know: You are 100% sure it's 33, no possibility of miscounting? Will save a lot of time looking up a blind alley if that's a potential explanation.

Assuming it is 33, can you take us some pictures of that thing appears to have been added behind the instrument pack? Also worth pulling the passenger footwell carpet, taking off the cover and having a good look/photo round the ECU loom to check for things that appear to have been grafted on round there as well.

Incidentally, if you're driving along the motorway at what should be around 70mph, what are you seeing on the speedo, 110-115 or so, 70, or something else?

Smo_GSR

Well, at ~4,400rpm (she's in limp mode) in 5th gear SatNav claimed ~90mph with a clock speed of ~150kph so they appear accurate enough. I'm certain it was 33 but I can always recheck. As for the photos I will get some taken.

It's frustraring as going into limp mode is stopping us enjoying the car to it's potential!

Smo_GSR

I think I've found the culprit - I pulled my clocks again today and this is what I found;







It appears to be a JDM delimiter of some kind - could this be the problem?

I did a hard reset on the ECU so was showing no faults then took her for a drive, she slips into limp mode with the CEL showing ocassionally.

Splitpin

Good work. It could be the problem but, without being able to see exactly how it's wired, the fact that it's behind the instrument panel suggests that it is *only* correcting o I highly suspect that it's *only* correcting the speedometer, and not the ECU. Additionally if your speedo needle's working properly without obviously dipping or cutting out as you drive, that suggests everything up there is as it should be.

Although it might be worth pulling all that tape off and checking the joints between the cables are as good as they should be.

May well be that there's another delimiter wired into the ECU loom so well worth pulling the carpet and cover and having a look for something similar down there. If you find one, chances are that's the one causing the problem.

Incidentally when you say the CEL's coming on occasionally since you reset the ECU, what's the fault code being reported? Still 33?

Smo_GSR

The fault code remains as 33, yes. I took apart my passenger footwell today and all seems well (see photograph);



It would appear to me that this is as normal?

I didn't get a chance to pull apart the connections behind the clocks just yet as I need the car this evening - but I will check them at the earliest convenience.

Smo_GSR

Today I managed to fix the problem. As per the image below;



I traced the red wire to a blue and pink one behind the head unit that it had been spliced into. I decided to completely remove the delimiter and reattached the wires the way they should be.

The car now drives perfectly, shows no codes and the CEL stays off.

Happy

weslatore

where is the position of cable on this pictures??? thx