Ford Focus 1.6 engine management light on

[yellowbentines]

Hi all, hope someone can offer some useful advice.

My sister-in-law has a 2003 1.6 petrol Focus, the engine management light came on and the car is running very lumpy and rough - I recommended a mobile mechanic/diagnostic chap I've used in the past but he's just been and charged her to tell her it could either be a pnp or cpp switch (but he doesn't know where either of them are!), or the ecm - his advice was to just keep driving it until it stops working!

So PH faithful, any advice? I don't know what these switches are but if there's a likelihood it's one problem over any of the others and could be tackled by my modest DIY mechanic skills I'll find out how to replace the part for her and see if it does the job.

[yellowbentines]

Thanks, it was just the one fault code apprently, which is 1709, if that means anything or helps?

ETA which translates as "Park or Neutral Position Switch out of Self-Test Range", but doesn't help me find out where it is or how to replace it - or if indeed that precisely narrows down the problem as he did mention CPP switch and ECM also however only that code came up.

Edited by yellowbentines on Wednesday 27th July 13:00

[yellowbentines]

Hmm, that's what I found on a list of fault codes I found, it sounds like it narrows it down or do you think otherwise? Electrics/electronics isn't my think (as you can't hit them with a big lump hammer )

A bit of further searching suggests that as it's a manual it doesn't have a PNP but instead has a CPP - clutch pedal position switch - they're less than a tenner on ebay so I wonder if it's worth replacing or am I throwing money away here if it is a more generic fault code than the code guide suggests?

[yellowbentines]

Cheers, she had taken it to her normal backstreet mechanic also this morning, but he's strictly an 'oily bits' man, but she said he checked plugs and coil pack and they were fine, not sure if he would've checked for vaccuum leaks.

[yellowbentines]

Baz Tench said:

The Coilpack or the MAF sensor would be the main two areas I would be concentrating on, given the symptoms.

Cleaning the MAF sensor is something within my limited mechanical capabilities, shall try later.

Any other suggestions warmly welcomed

[yellowbentines]

BUMP for the knowledgeable evening crowd!

I've cranked the engine with the plugs out, all are sparking fine so it appears the coil, HT leads and plugs themselves aren't the problem.

Airfilter looks new and I cleaned the filter box out, removed the TPS and it is spotless, the IACV also got removed and looked ok, a little sooty but nothing major I wouldn't say. I didn't have the right torx bit to remove the MAF but will do that tomorrow.

The best way to describe the engine now I've heard it is an erratic idle, it can run fine for 5 seconds then shudders/dies for a second then picks back up again.

Any ideas folks?!

[yellowbentines]

R1 CKY said:

I had a 1999 1.8 Focus that did similar to what you describe, although not noticeable when driving and didn't bring on the EML.

The idle was quite rough and you could see the rev counter moving about.

There was a vacuum hose with a split in it. IIRC it ran from the right hand side of the block, under the coil pack and connected on to something near the throttle body around the back of the block.

I actually still have the new hose in my garage as I taped it up as a temporary fix and couldn't be arsed to change it!

Cheers - how did you find the split, did you use the brake/carb cleaner method where you spray along all hoses until the idle changes, or was it easy enough to spot by eye?

The engine management light has gone off now, but the problem hasn't changed!

[yellowbentines]

Cheers for the help so far.

I've since discovered this 1.6 petrol engine doesn't have a MAF sensor, it has a MAP sensor which is located under the inlet manifold and appears like it can only be removed by firstly removing the alternator - I'm leaving that as a last resort.

On to checking for vacuum leaks - should I be using brake cleaner or carb cleaner (is either better and is either likely to cause any damage if it runs onto/into anything else?), and am I looking to hear the idle return to normal if and when I hit the leak, or should the revs drop or increase?

Thanks again chaps.

[yellowbentines]

Thread update/more advice desired!

I've ran the engine and sprayed carb cleaner everywhere, especially pipe connections and joints - nothing.

The engine is still rough - oddly its fine for the first minute or so after start-up when the choke is on, but once its off the engine "phut phuts", if that makes sense.

Any other ideas chaps, fueling system? I'm at a loss and my sister-in-law can't really afford to put it into a garage right now, I'm determined to get to the bottom of the problem!

ETA the engine management light is back on if that gives any further clue.

Edited by yellowbentines on Saturday 6th August 21:27

[yellowbentines]

Thanks JD, I'll look into the Lambda.

I'd thought about crap fuel, its always run on Esso from the same station, very busy station and I use it myself, never had any bother.

[yellowbentines]

Thread update - I know many of you will be waiting with baited breath

Garage 1, mobile mechanic, Pistonheads and myself all failed to diagnose correctly, garage 2 was tried and after a new water pump, thermostat & housing, fan belt, and all is well again - wish I knew how they diagnosed that for future reference.