28 replies to this topic

[wase16ll]

no worries, good luck

[Giffer2]

The cat code is probably the cause - not the cat itself, but one of the sensors is probably gone and its probably the post cat sensor, the values whilst the engine is cold are out, I'd hazard a guess that even when warm it's probably not pulling as well as it could do.

[becksta1234]

thanks , it usually seems to drive fine once engine is warm 

[wase16ll]

would be unusual for a bad oxy sensor preventing car starting from cold, as these sensors dont even come into operation till engine has started and sensors are heated up..
if you or you know someone handy with a voltmeter, easy to test temp sensor..
from memory its a 2 wire sensor....white/brown wire
disconnect sensor...carry out resistence test on sensor.
cold engine should read approx 39000 ohms
hot engine about 2000 ohms

reconnect sensor, volt check with ignition on
brown wire is earth, 0 volts
white is signal wire, cold engine approx 3.5v, hot engine, approx 0.5v.

if as above, sensor itself is ok.

these figures are for 1.25 zetec, think all the fiesta zetecs will be same , but if you have different engine let me know and ill check

[becksta1234]

ok thanks i have a 1.4 fiesta zetec 

[wase16ll]

figures are the same

been thinking about this [dont forget suggestion of checking plug gaps put up earlier]
those 2 codes are a strange combination, not come across this before.....making me think you might have an earth fault somewhere on the engine, its the only thing i can think of that makes sense of those 2 codes..

so if it was me, i'd check those gaps, test the temp sensor, check the earth wires [can look up where they are if your interested]...failing that, it would most likely need a full diagnostic from somebody that knows their way around live data...

[becksta1234]

ok thanks yea if you dont mind 

[wase16ll]

will take a while, but what the hell....im bored

note to self.....

must get a life

[Giffer2]

The speed sensor is a common fault, either the sensor has gone or the ecu needs a firmware update. It's unlikely to be connected and isn't the cause of the fault but is stored as a code.

Isn't the pre-cat O2 sensor a 4 wire heated type on that engine? Either 1 or both sensors are faulty or the engine thinks its at temp before it is which is then kicking the O2 sensor into life which is then making it run lean and cutting out?

[becksta1234]

thanks every1 will have a look into things and see what happens 

[wase16ll]

giffer...thats my first thought, temp sensor is faulty, causing it to struggle starting, oxy code is throwing up as they think engine is warm, therefore fooling ecu that oxy sensors are outside of parameters.
sensors are 4 wire, they are heated so they kick in earlier, but they wont prevent car from starting, which became an issue, takes a few minutes of engine running before they come into play...hence why engine should be warm/hot before emmissions test at mot.
ecu relies far more on temp sensor in first few minutes of starting, in how much fuel/air required to keep her running.
you could have a point re speed sensor, it is a common fault, it could quite possibly be totally unrelated as its possible this code wont trigger the warning light, so may have been there long before problem started. will still remain once this problem is sorted

just in case, related earth points are
battery negative terminal, earth close to battery tray and gearbox bellhousing
earth points also at n/s/f chassis leg, n/s/r near lamp unit, o/s/f under dash just in front of door pillar, o/s/f close to seat belt mounting just behind drivers door.

[becksta1234]

thanks will keep every1 updated on what the problem is 

[becksta1234]

just got my car looked at and sorted out turns out it was just the battery after all the suggestions of what it could be haha but thanks for the advice everyone 

[Giffer2]

The simple fixes are always the best and normally the cheapest!