Engine Management Light has come on

[Martin6]

Hey guys, 

Leaving work the other night, I noticed that my orange engine warning light had come on. The car was still driving fine however and I was able to get home with no problems. I did some searching on the internet and found out how to view the error codes on the cars computer, and it displayed E197 and E200 which are issues relating to the speedo/odometer I believe. I took the car out for another drive today and the light is still on, however I noticed no problems with the speedometer or the millage counter etc- it seemed accurate. I then repeated the method to find the DTC error codes, but this time it said "none" and didn't list the two I had previously. 

I'm wondering whether I should take it to a garage (can't really afford to get any repairs done at the moment as on a student budget!), or whether to somehow just clear the engine warning light, since the car is working fine and it now displays no error codes. Any advice would be great! :)

Car is a ford fiesta style climate from 2005, had it's MOT in August and went through all fine. 

[isetta]

you need a OBD code reader which can read the codes and clear the light. I use the 'modified' type which has an extra switch for more functions on Ford cars. Mine connects to my laptop using USB cable and then I use free software on the laptop. 

This seller has been recomended many a time on this forum

https://tunnelrat-electronics.fwscart.com/

Every ford owner should have one.  A garage will charge more to read and clear codes then it costs to buy one

[Martin6]

18 hours ago, isetta said:

you need a OBD code reader which can read the codes and clear the light. I use the 'modified' type which has an extra switch for more functions on Ford cars. Mine connects to my laptop using USB cable and then I use free software on the laptop. 

This seller has been recomended many a time on this forum

https://tunnelrat-electronics.fwscart.com/

Every ford owner should have one.  A garage will charge more to read and clear codes then it costs to buy one

Thanks for this 🙂 This is exactly what I did- I bought an OBD code reader from amazon which arrived today and have just scanned the car. The only code that came up was P0030 which is the H02S bank 1 sensor 1 heater circuit. I have also cleared the code and the engine management light has gone off. 

I'm not sure what to do now really, would I be safe in just leaving it for now and using the car as normal since no error is showing now? Or will the engine blow up if I don't get it looked at? 😂

[isetta]

I don't think there is a danger of damaging anything with the code you have.

I would drive it and check the codes again in a couple of days even if the light does not  come on. not all codes activate the light. The annoying think about reading the codes is that it does not show a date. So if you read the codes and find eg. 3 codes you do not know if they all appeared at same time or some are old. So you need to clear all, drive and see what reappears. I know it's not quite the same as yours as you had one code.

Your code relates to the heating circuit in the oxygen sensor in the exhaust. This sensor affects exhaust emmisions, if the heater in the sensor does not work then the sensor won't work so effectively when the engine is cold. It's not a big deal to the longevity of your engine. 

I would have thought this code would come back. It's does not sound like one which would be a one off and never reoccur.  I do not know if it is common for the heater in the sensor to fail. Might be dodgy connector on the wires to the sensor,

[Martin6]

Just an update on this, the next time I attempted to drive the car (about a week later), I wasn't able to start it. It was making a weird noise from the front too and just wouldn't start properly. Eventually after holding the key for a very long time and repeated attempts I did get it started and it seems to start with no problem now. I'm just wondering what could have caused this and is it related to the engine warning. The warning light has now also come back on but the car seems to drive ok. 

I'm thinking I'm going to have to take her in to the garage! 😞

[JohnF]

We have an X reg  Focus 1.6 Zetec auto estate 134,000m and a few months ago the EML light came on occasionally for no obvious reason, easily cleared by disconnecting the battery for a few minutes.  The only time it had done it before was when it suddenly started misfiring owing to  coil pack failure at 125,000m.  The cambelt (inspected regularly), HT leads, all sensors and air filter (brushed clean every 20,000m or so) are all original and plugs less than 50k old.  The engine also occasionally died after idling when coasting down a long hill.   Searching for possible reasons I came across loads of technical coding suggestions (I haven't got a code machine) for replacing O2 sensor,  mass air flow sensor etc....but the suggestion that made most sense was a USA u-tube video describing dirt/carbon build up on the large butterfly valve in the throttle body. This is precisely designed to not quite close, so the engine can breathe at idle.  So I pulled off the wide rubber intake hose, and cleaned the sooty edges of the white plastic disc with a bit of rag wrapped round a length of thin clothes hanger wire soaked in petrol.  (It says 'do not clean' inside!  - apparently the circular flap valve is coated with a special substance).   After several hundred more miles, the  EML has stayed off and it no longer occasionally dies when coasting down long hills.   So before you waste money needlessly replacing sensors, I suggest going back to basics and try this first!   Hope this helps...

Edited November 26, 2018 by JohnF
left out 'Focus'