Yellow Engine Light - Engine Diagnostics

cosb6 · Unread post by **cosb6** » 15 Feb 2006, 16:08

GRRRRRRR.....

The engine light on the missus car has come on. The manual says something about it being Fuel Injection / Environmental Systems error. Basically it's the little engine light...

Any ideas what this is likely to be, or is it a Citroen Only jobbie....

Regards
Stuart

dnsey · Unread post by **dnsey** » 15 Feb 2006, 16:18

Could be all sorts of things - needs the diagnostics read really.
Were / are there any symptoms? If not, it might just have been a glitch, and the light will go off again eventually.

cosb6 · Unread post by **cosb6** » 15 Feb 2006, 16:27

Hi...

The missus says it came on this morning, on her way out. She drove about 10 miles, and came about about an hour later, and the light came on again after she started the engine.

There is nothing noticable at all, it's just a light is on. I guess it's best not to drive it (the garage can't fit it in for a week)..... but as you say could be anything...

I didn't know if Temp sensors, or Lambda sensors or something like that were favourites to go....

dnsey · Unread post by **dnsey** » 15 Feb 2006, 17:25

Personally, I wouldn't worry too much if it's running OK. I'd give it two or three days and see if it's still on - but you must judge for yourself.
You may well find that it's gone out again by the time it gets to the garage!

jeremy · Unread post by **jeremy** » 15 Feb 2006, 18:02

Sorry - I'm not as good at guessing as some - What car is it, fuel, engine, year, would help a bit.

AndersDK · Unread post by **AndersDK** » 15 Feb 2006, 18:13

No sensors are favourites on such a general fault indication.
The engine fault lamp would light up on anything the ECU detects as a problem - for long enough to be detected.

Could be a very simple problem with air intake filter clogging up - or a MAP sensor having a game with you.
There is no problem still driving the car with this fault lamp. It just indicates that the car needs attention.
If the engine had a serious problem like low oil, or low coolant - you would get the associated red warning lamp.

You assume we all remember clearly what car your missus are driving ?
( I dont

)

cosb6 · Unread post by **cosb6** » 16 Feb 2006, 12:53

Hi...

For not mentioning any details about the car can I have the "Dump post of the week award" then....

Right... the car is a 2001 Y plate Citroen Xsara, 1360cc. It's due a 72k Major Service (inc. Belts), so maybe the service will fix the lights. I know it's not had plugs / air filter for 24k so it's all due.

stevieb · Unread post by **stevieb** » 16 Feb 2006, 20:43

Sounds like air filter might be your problem.

My 406 light comes on and stays on with higher octane fuel in the tank. Regular 95 RON stuff is fine.

I suppose a slightly bunged air filter would richen the mixture disproportionately, maybe more so than the engine management wants to compensate for. I think the high octane in mine has a similar effect. It's just asking too much of the engine management to compensate for the extra bang you're getting.

(And the extra fuel consumption, etc. I know, I know

)

cosb6 · Unread post by **cosb6** » 17 Feb 2006, 08:47

I'll give that a go and let you know how I get on....

Gavin123 · Unread post by **Gavin123** » 17 Feb 2006, 09:24

Hi, I mentioned this before on here, you can reset it using an ELM323 OBD2 ISO Interface with MCU Read DTC/Data Stream. You will find them on eBay, or just search for this seller on eBay easy51688 I think it cost me around £40.00.
My light came on around that mileage and it was the 02 sensor, tried resetting the codes and it went off and has not come back since.

cosb6 · Unread post by **cosb6** » 17 Feb 2006, 11:49

So now the light is on, even if I fix the fault it will not go away? I just remember the old PUG106 I has it went off on it's own when I fixed the problem.....

dnsey · Unread post by **dnsey** » 17 Feb 2006, 13:16

I think that once the fault is removed, the light's reset automatically after a number of restarts of the engine (I can't remember how many).

cosb6 · Unread post by **cosb6** » 06 Mar 2006, 12:56

Hello all...

Just a bit of an update on this. The car has been in the garage having a new bumper fitted (which has taken over 2 weeks), so hasn't been into the dealers yet to have the light investigated.

It's going to have a 72k Service tomorrow, and I'm going to ask them to get the fault codes for the light too. The service should include the hookup to diagnostics, so that should be part of the service... however fixing any fault might not be. It's not running right when cold, like a missfire, so the light may be indicating that. The 72k service is (by the look of the book) as big as it gets, including PLUGS, CAMBELT, ETC... ETC, so it's likely to be in the region of £350 anyway, so I'll see how it goes.

cosb6 · Unread post by **cosb6** » 09 Mar 2006, 08:33

The Problem has been diagnosed as an "upstream O2 Sensor" which I assume is the one in the Manifold before the CAT. Dealer Price for the part alone is £140 ish.... but Euro Parts doesn't list them, and GSF only has them for the older model (single Probe) whereas ours has a Pre and Post CAT sensor.....

Does anyone know if I can get the bit from anywhere other than a dealer?

AndersDK · Unread post by **AndersDK** » 09 Mar 2006, 11:10

I'd say this is way too early for a Lambda probe to fail.
Investigate the wiring & plugs to that probe - you may find your luck there. The sensor will look something like a spark plug screwed into the exhaust.

Note : a Lambda sensor (not a "cat" sensor) is a generic sensor meaning its all the same type no matter model, year & make. Its just the physical layout and the wiring plug that differs.
The connection is also generic : 2 wires for the pre-heater element, 2 wires for the sensing element - thats a 4wire sensor. A 3wire sensor is exactly the same - its just that one wire is common for both heater & sensor - as this would be an earth wire anyway.
Plugs in directly no calibration needed.
Only takes a bit of thinking to make any sensor fit any car.

The reason for 2 Lambda sdensors on latest cars is the ever growing demand for pollution control. The 1.st ("upstream" before the cat) is the usual sensor known since they invaded our engines. The 2.nd ("downstream" after the cat) is sort of a "pilot" sensor sensing if the cat is still working within demands.