engine management light

[rjg22]

I posted this in the fiesta section but may be more use in this section:

I posted earlier in the week about my engine management light coming on due to a problem with the cat and I was told I needed the codes. I now have the coades and wondered if anyone can help! Codes are:

P0420 Catalyst system efficiency below threshold

P0460 Fuel level sensor circuit malfunction

Can anyone shed a bot more light on the situation?? Its on a 52 plate mk 5 zetec-s if that makes any difference!!

Thanks

[sr-performance]

Hiya mate, i think your cat may need replacing and does your fuel gauge work ok?

steve

www.sr-performance.co.uk

[Grilled]

Could be your lamba sensor?

[sr-performance]

hiya grilled, codes he gave me came up with the above, no probs with lambda which usually pack in first.. :)

steve

www.sr-performance.co.uk

[squaddiefox]

agreed with SR, the cat will need replacing as it has probably broken up. quite pricey aswell for what they are. might be wortyh trying a decat pipe??

[ssauk]

Found these codes and possible cause

PO0420 - Catalytic Converter system, bank 1, effiecency below threshold - Possible cause - Catalytic Converter, Wiring, H02S2

PO0460 - Fuel Tank Level sensor, circuit malfunction - Possible cause - Wiring, Fuel Tank level Sensor, ECM

Hope this is of use.

Daz

[Fanta]

My '02 Fiesta has been suffering with the P0420 code since I bought it in Nov 2010, and I'd like to share what I've learned.

• The engine light (MIL: Malfunction Indicator Lamp) came on in less than a week of buying the car - I disconnected the battery a few times, but the MIL came back on.
  
• I bought a £25 OBD-II scanner that plugs in to my laptop - I was amazed with how many sensors are on the car. A lot a time was wasted with the scanner, I didn't solve the problem, but I learnt a lot about OBD. The handiest feature was being able to reset the MIL without disconnecting the battery.
  
• P0420 basically means the catalytic converter isn't working efficiently - it isn't doing its job in breaking down the emissions.
  

(oxygen sensors)

When researching about P0420, you'll read about additional checks towards other components that could be causing the P0420 - I had both sensors replaced, which made no difference other than put a dent in my wallet. When you think about it, if the sensors were faulty there would be another code saying so!

I was told to buy a genuine Ford sensor, but the one I bought from Eurocarparts was half the price. Comparing the original oxygen sensor to the new NGK, I noticed that they were exactly the same - the original "genuine" Ford sensor even had NGK printed on it.

After this my Fiesta passed its MOT with the MIL on, well I actually turned it off just before the car went in and it came back on after the MOT. They did say that the emissions were high and very close to failing.

(Ford specialist)

I took my car to a so-called Ford specialist and had a chat about the P0420 code - they said when this code is displayed by itself, it puts no other component to blame other than the converter (a very good point to remember).

I didn't get it repaired because it had just passed its MOT and I had a year to see if the converter would sort it self out - perhaps clear itself of any clogged deposits inside the converter.

The quote to replace the apparently faulty converter was about £550 for a genuine Ford converter and then you'd have labour + VAT on top… very expensive!

(Cheap converters)

There are considerably cheaper aftermarket converters available , but they are cheap for a reason and will only last a few years.

I've had experience with this when my 106 's converter fell off the car while driving - I replaced it with a £40 aftermarket converter (instead of Peugeot's £430), then about 5 months later it failed its MOT on emissions. Luckily I had a 2 year warranty on the converter and had it replaced.

For the next year I coved up the MIL on my Fiesta to ignore the P0420 code - I plugged my laptop in occasionally to check the MIL, but it's never turned off.

(Exhaust)

A year had passed and I hadn't made any attempt to fix the P0420 headache, but I thought I may have found a solution when working on my girlfriend's Ka.

Close to the time when I bought my Fiesta, the Ka's emissions was borderline a pass and I instantly thought the converter's on its way out.

The Ka had a very noisy muffler and I could see by its size that it was a cheap aftermarket one, so I replaced the muffler for a genuine one from Ford for £60. When I took the aftermarket one off loads inside lining fell out.

The genuine muffler is so much quieter compared, and a month later it passed its MOT. The emission figures had dropped significantly compared to the previous year.

This got me wondering if my Fiesta was having the same problem - a leaking exhaust can be one of the causes for P0420. The exhaust on the Fiesta is the original from new (10yrs) so it's possible that the muffler has deteriorated.

Replacing the exhaust may stop the code showing, but I have yet to prove it. I spent a lot of time scouring the internet learning and looking for the cause of this code - I did read about checking for exhaust leaks, but didn't think to check the mufflers efficiency (back pressure).

I'll reply when the weather's warmer and I've fitted my new exhaust. I just want people to consider this before forking out loads of cash on a new part that doesn't need replacing.

[Fanta]

• So prior to my MOT I fitted the new genuine back box and centre piece
  
• Reset the MIL and went for a long drive while recording the data
  
• The MIL came back on for the P0420 code
  
• So changing the exhaust did nothing
  

My car had its MOT, I didn't mention the code, the MIL was on but hidden, and it still passed! Nothing was said about the emissions and the figures were good. I don't get it.

I give up, but these are my last thoughts on the matter. The only way I can monitor the catalysts performance is by viewing the oxygen sensors on a graph, this way I can compare my previous readings and see if there's any change, if there isn't then I can assume the catalytic converter is fine and will pass.

This graph is showing 30sec. The left half is at idle and right is 2500rpm. The red line is the oxygen sensor before the cat and green is after. Red line is fine, but the green should be a steady horizontal line. The green line following the red indicates the cat isn't working correctly.

The previous MOT test said the emissions were high, but this could've been because it was a frosty cold day and they didn't let the engine warm up enough - the cat works properly when it's really hot. It also didn't help that I took the heat shield off, this would obviously help keep the cat hotter. I've put the heat shield back on now.

I didn’t mention that I tried a product called 'Cataclean' last year, this was after an MOT. I didn't record the data, but it did something because the MIL went out and stayed off... until I refuelled. It does something to lower the emissions, but only lasts with the tank of fuel that it’s in with - good I guess if you know your emissions are high.

It seems that the parameters for the oxygen sensors are too sensitive - it's warning me that the cat isn't working properly. I'd rather the garage told me when the cat was failing rather than the car, and it’s annoying that the MIL is always on because I'm not sure if it's effecting the cars performance.

The reason the MIL turned off on motorways was probably because the cat reached a more efficient operating temperature than it usually does.

I've come across a garage called 'Pumaspeed' who say they can change the parameters of this sensor to stop it coming on, costs about £70. It's mainly done for sports exhausts where the rear oxygen sensor can't be connected, and if it's not connected then the MIL will always be on.

For me, the key thing to remember is - if the engine wasn't functioning properly there'd be a code, and if a sensor wasn't working there'd be another code. I only have one code and it points to the cat, and there probably is something wrong with it, but it works well enough for me to leave it alone until an MOT test says otherwise.

I'll probably consider having the parameters changed, so I can see the MIL if something else went wrong.

I found these two websites interesting to read, which helped me decide that the converter is probably less efficient than it used to be -

http://www.batauto.c...les/catfailure/

http://www.autoshop1...m/forms/h64.pdf

It doesn't help that I don't have any history for my car, but I can only assume that something has happened for the converter to deteriorate.

Remember that I'm no expert in this matter, some of my technical talk might be incorrect and the scan tool I use probably isn't as sophisticated as what professionals use.

[btmaldon]

Had a P0420 come up on the wifes SportKA about a month ago. I erased the code with my scanner, took the car for a good blast and it hasn't come back since. It must have just been a blip.

[Fanta]

To stop the MIL coming on I tried a "Mil Eliminator", which I bought from pumaspeed.co.uk. This only worked for a few miles because it's designed for de-cat exhaust systems where the emissions are higher.

So my second and cheapest option was an "O2 spacer" bought for £7 on eBay. I put it on about three months ago and the MIL hasn't come on once. All it does is pulls the sensor from out the exhaust so it's not in direct flow, which means it gives a weaker/false reading.

Unless the Cat' got worse since last year, it should pass the MOT fine.

I spoke to pumaspeed about having the parameters changed on the ECU and that would've cost a few hundred.

[soapy67]

Hiya mate, i think your cat may need replacing and does your fuel gauge work ok?

steve

www.sr-performance.co.uk

how do I post a querie on the site from an ipad

[soapy67]

how do I post a querie on the site from an ipad

changed the fuel filter today on the 1.6tdci mk2 focus because just driving along and it cuts out all the dash lights stay on but when I turn the key nothing I leve it for 5 mins put the key in the door lock then unlock and it starts again and away it goes till it happens again anybody help it's not the fuel filter pleaaaaaaseeeee help anybody

[MikeyPaine]

^ probably a cluster fault

[shaunytee1600]

Understanding lands/02 sensors

Power is nothing without control .

[MikeyPaine]

That code is for the pre cat sensor right? So if the pre cat sensor is faulty. It stands to reason that it isn't the cat. Is wager the sensor is only picking up and sending a voltage when revs are massively changed. Change the pre cat lambda sensor.

Blue blooded

[Splodge]

Hi, new to the forum. Have spent many hours trying to find an answer but no joy so I'm hoping someone here can help?

Sorry, to jump in on this topic but I can't seem to start a new one yet.

Anyways, message i light flashed red on my 2009 Focus 1.6TDCi Zetec for about a minute whilst driving. There were no messages at the time and none in the message memory when I checked later. It may have occurred shortly after I restarted too quickly from a stall. No other warning lights. Just a glitch or something to be taken more seriously? Thanks.

[jeebowhite]

have you checked for error codes?

[Splodge]

By doing the dash trick? No, I shall though. Thanks

[jeebowhite]

That's one way your best bet is having an error code reader. Check my signature for 'got an error on your car for more details'

[micky21]

got the engine warning light just come up on my 2009 titanium feels juddery when driving any ideas why

[Goodkat]

Get your codes read Mickey, that'll be best

Sent via the 'Clacks'

GNU STP