1.2 12V engine light and bad performance

[Minim]

Hello

Like the topic states I got a engine light and bad performance on my newly bought polo 2003 1.2 12V. I'm not used to this car/engine but it also needs 5-6seconds cranking to start and to me that feels long. It also seem to hit a rev limiter at 3000rpm prolly due to limp mode. The workshop that sold it to me replaced the camshaft position sensor but it didn't help. I have cleared the fault memory and these codes are the ones left at the moment. I measured the camshaft sensor connector with ignition on and read 5.00V on pin 1-2 and 2-3 (0V on 1-3).

Is there a quick way of checking engine timing or does the whole cover need to come off?

Engine module
2 Faults Found:
16726 - Camshaft Position Sensor (G40) P0342 - 35-00 - Signal too Low
17851 - Potentiometer for EGR (G212) P1443 - 35-00 - Signal too Low
Readiness: 1110 0101

ABS modul
1 Fault Found: 01314 - Engine Control Module 013 - Check DTC Memory

[Minim]

Not sure how to edit post so I'll just make a new one. Today I opened here up and checked that the marks on the crank sprocket lined up with the dot at the other sprocket and then the camshafts was lined up from what I could eyeball on the other side of the engine. I didn't have locking tools so it was just done with eyes to measure but it didn't look like it was off at all.

any other suggestions to where I should look?

[RUM4MO]

If you are not getting any replies on this forum, maybe search further, ie on the Skoda or SEAT forums? http://www.briskoda.net http://www.seatcupra.net Both the Fabia and Ibiza used these engines. I'm lucky as I have not had a car with that engine, sorry!

Edit:- editing your postings, I could be wrong as far as this forum is concerned, but some forums stop you being able to edit a posting after a certain amount of time.

Another Edit:- what I wrote about editing on this forum is not true for this forum, a posting from a week ago is still allowing me to edit it - for editing, select the "pencil" graphic, make the changes then submit.

[Minim]

Ok thanks for the suggestion I found out that it's prolly down to a electrical problem since I now keep getting back a map sensor open or short to ground error and when I do a readout with ignition on and motor off I read 850mbar. I'm not sure how accurate the map sensor of the polo but on my bmw my map sensor reads athmospheric pressure 1000-ish mbar in the same state. Guess I have something pulling down signal levels or a bad earth connection somewhere. Does anyone have schematics for this one?

Lucky to not have had this engine? Is it a problematic one? I really bought this car only because it was almost given away to me and because I have a BMW M5 with 5L V10 that I don't like to ride on the winter and I just wanted some economic car to do boring non-inspiring driving in After buying it it really surprised me with beeing kinda fun to ride in it's own way. Sure it has no power and handling isn't exactly sharp but it has it's charm

[RUM4MO]

Yes I think that that motor had some annoying problems, but I understand why you might not want to use the M5 in winter! My car is an Audi S4, but it sleeps in my garage most of the time as I am looking after my daughter's 2009 SEAT Ibiza 1.4 (85PS) SC, so use that except when there is ice or snow, then I use my wife's new VW Polo 1.2TSI 110PS with winter wheels/tyres on! If the weather is really terrible in winter I might just take the S4 out with its winter wheels/tyres on, but then I would have to try to clean it, not easy in low temperatures!

Maybe take the MAP sensor and wash it carefully using just brake cleaning fluid - do not spray directly into the MAP sensor, do this about 10 times! Normally the EGR valve on these petrol engines keeps clean, unlike derv engine ones. I hope that you get/find better answers in the other two forums - or Google.

[Minim]

Is the MAP sensore the same as the MAF sensor on these engines (MAP=instake pressure, MAF=Airflow)? The EGR valve is brand new but still throwing errors and the same goes for the camshaft sensor. This is why I'm leaning towards a eletrical error but I don't have much experience with VAG.

[RUM4MO]

The new EGR valve really needs to be to be "introduced" to that engine by running basic settings so that the potentiometer voltages can be stored for fully open and fully closed, though I would expect these valves should not vary much between ne EGR valves.

MAF, tends to be a hot wire anemometer device, these engines use a throttle body with a potentiometer to give positional feedback and for air volume, maybe, they use a pressure sensor, MAP located in the inlet manifold, whereas a MAF tends to be located further away in the inlet air trunking. I'm guessing that using MAP and calibrated throttle body is better than the old way of measuring the air flow.

I'd guess that you can take the MAP sensor off easily as it will be secured by one or two screws and its O-ring seal, which stays on the MAP sensor is re-useable. Probably find the MAP sensor on the RHS of the inlet manifold. These were modified at some point as when I temporarily swopped the one on my wife's old Polo with a 1.4 16V BBY engine for a used one bought via ebay, the original one was a newer version of what I fitted. I'm not too sure about the 1.2 engine, but where the pipe from the EGR valve connected to the throttle body, there was a blockage caused by the hot exhaust gasses coming into contact with the oil being fed into the engine via the crankcase ventilation system.

[Minim]

Ok I found the wiring diagrams for my car and it seems that the G212, G71 and the G40 share a common 5V supply line and a commong ground point. Since those 3x have an error I'm pretty sure the problem is somewhere in the supply chain and not in the sensor themself. It could ofcourse be a sensor failing and pulling down 5V to ground causing a error. I'm 500km away from the car at work but this weekend I will do some more measurements.

Edit: on a second look on the schematics I notice that the ground point is not common as the G212 don't have grounding and the G62 (collant temperature) seems to give a good reading and that have the same common ground as G71 and G40 sensors. So then I'm down to a error in one of the 3x components, a broken 5V supply or a ECU 5V supply fault. I can't wait to get my hands on the car to do some measurements

[Minim]

If anyone else stumble upon this thread. The problem was the 5volt supply lead that was almost off in the engine wiring harness where it exits the heat shield of the cables down at the gearbox. Fixed that and went for a test drive now with no error codes.

[Calrob98]

Hello, I have the exact same problem! Can you help me find out what 5v wires I should be checking?

[Minim]

sorry for the late reply. Check this wiring diagram.



and a photo of my cable.

[RUM4MO]

Oh, that is very nasty looking!

Edit:- same type of pattern/wear on the blue and brown leads, is that being caused by the protective trunking crushing that bundle of wire?

[Minim]

I think it's caused by wires that are bonded to hard togheter and vibrations. I did loosen it up a bit so they don't work on eachother when the engine moves.

Didn't have any troubles after I did this fix. Well.. it only starts on the second attempt (no matter how long i try on the first) but I think this is due to engine timing. I have a new chain kit lying here so I'll swap that when I get time to see if it works out better.

[LorenFdez]

I think it's caused by wires that are bonded to hard togheter and vibrations. I did loosen it up a bit so they don't work on eachother when the engine moves.

Didn't have any troubles after I did this fix. Well.. it only starts on the second attempt (no matter how long i try on the first) but I think this is due to engine timing. I have a new chain kit lying here so I'll swap that when I get time to see if it works out better.

Hello, I´m new here. I have got the same problem. My error says:
"1 Fault Found:
17851 - Potentiometer for EGR (G212): Signal too Low
P1443 - 35-10 - - - Intermittent1"
The EGR is new, so there´s not the problem.
I have made a few measurements. I see that in the whole potenciometer there are 5 Volts, but these aren´t constant, so I think there´s a problem with the wire as it happens to you. First thing I want to do is to find the D141 conection to see if there are 5 CONSTANT volts there, but I dont know how to find it. Anybody knows where is it?
Thank you

[RUM4MO]

Did you "align" that new EGR solenoid valve assembly to your car by using "basic settings" so that the car's engine's ECU knows the position that the EGR solenoid valve is current at?