Hi, New to the forum with a bit a problem.

My wife came home last weekend with an engine warning light on the dash of her 07 fiesta, i did the dash diagnostic thing and it came up with an error about the battery dropping below 10V, I had a new battery to put on it as it was struggling with the cold mornings so i fit the battery and did a google search and the forums said to check the rest of the fault codes with an ODB2 reader so i got myself a reader and checked the codes out last night which came up with a fault on the HO2S Heater Control Circuit B1S1 all the advice said to reset the code and see if it comes back on after a test drive so i reset the code and went to fire up but it wont start. Dash lights up, fuel pump kicks in turns over but wont fire. The Engine warning light is still on but there are no fault codes.

Any Advice would be great.

 

Pete

Hi is it petrol or diesel.   I don't really have any helpful comments to make. One comment I would make that is not that helpful at the moment is in future do not try to fix more than one thing at a time. If you do one thing at a time and check all is fine after each thing you do then if there is a problem it is easier to know where it went wrong. I don't really know why either of the things you did ( change battery and use fault code reader to read/clear codes) would cause this problem

HI, Its a Petrol. Just so you know i didnt try fix more than 1 thing at a time. I replaced the battery and the warning light was still on so thats when i got the code reader to check what else it could be.

did the engine start after replacing the battery before connecting fault code reader?

Just one thought, you say you had a battery ready to put on it, how long was that stored for before you fitted it? Was it charged up when you bought it? If it wasnt charged before you bought it or you've had it sitting around for a few weeks it might be fairly flat by now.

 

for the fact the engine is turning over means the battery has enough juice. You need to check and see if you have fuel and a spark. 

Dont know if it helps but in my mk6, once before i changed the battery but it wouldnt start as for some reason when i replaced the battery the fuel cut out went on. Dont know if its the same on the 09 but mine was behind the glovebox where the fuses are, but up and left from the fuses was a yellow button. 

Other than that, have you tried jumping it with leads then give it a good run for half hour or something sitting on the drive? Might be worth a go

Thanks for your suggestions, It tuned out the engine had flooded so i just removed the plugs and dried them out and it fired up 1st time. Warning light went out and took for  short test drive and all seemed well however when the wife came back from work in it the light came on again untill the car was warm then it went off again so im going to replace the sensor and see what happens.