VW Golf FSi 1.6 BED 2004 - Multitude of fault codes #
Posted by Pete Mutlow on February 13, 2012, 8:03 pm
Year of Manufacture *: 2004 Engine Size and Code *: 1.6 ltr BED ( Optional ) Scanner Used: ACR4 G2/C Reader V ( Optional) Fault Codes: As Listed
Evening All,
Would appreciate some thoughts on this vehicle.
HISTORY Vehicle was purchased about 3 months ago and now has 83,000 recorded miles. During that time, the vehicle developed a fault and the dealer replaced the NOX sensor. Soon after, a gear box mounting failed which was repaired and then the EML illuminated. A VW Specialist declared that it required a new throttle control motor although it had a multitude of fault codes. Customer wanted a second opinion from me.
SYMPTOMS Vehicle will drop into limp mode when driven at about 3000 rpm and the APC warning light will illuminate in addition to the EML light.
TESTS Scanned all relevant sensors and all ok except for post cat lambda sensor which was reading 0.14v. 4 Gas emissions were all within spec. Vehicle behaved well whilst under test. Vehicle is fitted with NGK plugs and number 2 was inspected and cleaned. Throttle motor plate was carefully cleaned.
FAULT CODES
P2096 Fuel Trim P2138 Throttle Position sensor PO688 Throttle Actuator P2202 Nox Sensor - short to ground P2201 Nox Sensor - Circuit/range performance 16684 Misfire 16686 Misfire cylinder 2 18354 Coolant Fan? 18528 Post Cat Lambda Sensor - too lean 16575 Fuel Pressure sensor
I have cleared down all the codes and will revisit the vehicle later this week to see what codes have materialised. I am not too familiar with the workings of the NOX sensor but I understand it has its own controller somewhere. I have also read that the NOX sensor on these vehicles have been subject to recall and soft-ware update. I am minded to change the NGK plugs for OEM plugs in view of the problems that can be associated with them. Also, I will need to check for earthing points around the gear-box area.
SUMMARY Basically, I am looking for a "heads up" and thoughts on the points raised prior to my next visit. Hopefully, there will not be a multitude of fault codes to consider!
Even as a VW specialist I hate these FSI engines. They're a money pit.
The NOx sensor is a common failure and is generally hard wired to the NOx control unit. There is also a software update which I would of thought the dealer would have applied when changing the sensor. Post cat sensor is part of the NOx sensor.
The rad fan fault code is also common on the mk5's. One of the fans will have stopped working - a new fan will fix it but the remaining fan is perfectly ample. It just runs at full speed more often. Personally I'd ignore this one if the customer will too.
The only faults that will put it into limp are the throttle and fuel pressure so I would be checking the serial data and scoping. I've also replaced engine ECUs on the FSI but they usually give more pronounced faults like failing to start when ever they fancy. Check for wiring breaks near to plugs on the items with faults - seems to be getting more common.
Hi Pete I think you probably have more than 1 problem on this car. But If the car is going into limp mode I would think this is to do with fuel pressure or the throttle codes.
I would scope the throttle body, scope both the position signal wires and the 5v feed and the ground to the sensor while doing a WOT test with just ign on.
Look for drop outs in the position signal as any kind of descrepency will set throttle codes, flash the lights and put the vehicle into limp.
The plastic teeth wear in the throttle body and the throttle flap opening is not smooth.
I posted a similar problem in the fixed and gone section. 'Audi S3 throttle malfunction' with pics of what I mean. My problem was also at 3000rpm.
This might not be your problem but it may not be a bad place to start.
Is that engine code correct I can't seem to find it on autodata when I was looking for the wiring diagram to have a look? or could it be code BAD?
Also Is it the APC or EPC light? I can not seem to find any info on APC light. If you know what it means could you let me know?
Thanks for the info so far. Just to clarify a few points:
1) The NOX sensor was replaced by the car dealer where the customer bought the car....not the main dealer. I suspect no soft-ware update was carried out.
2) EPC warning light which according to UKAT abbreviations is Electronic Power Control or Electronic Pedal Control.
3) I think the engine code is BAG. I will confirm this on the next visit.
I have been trying to copy the info from a poor duplicate Vehicle Test Record sheet. Sorry about that.
Went back to this vehicle today after EML illuminated again plus EPC warning light flashing sporadically. Vehicle has not yet dropped into "limp" mode.
To confirm, the engine code is BAG
LTFT was 8.58%. Don't think that is too high.
Spark plugs changed to OE Bosch
Fault codes present:
P2201 NOX sensor circuit/range performance. Presuming the NOX sensor has already been changed, I am assuming that the soft-ware upgrade has not been carried out.
P2138 Throttle Position sensor. Graphing the sensor found no gliches.
17413 Torgue difference cylinder 2. This is a new code although 16686 (cyl 2 misfire) was present last time. Understand this could be an injector or engine problem. Vehicle runs fine with no discernable misfire.
17443 NOX Signal implausable
18047 Pedal Position Sensor
16500 Coolant Temp Sensor. I understand this to be one of the two sensors which command one of the fans to run.
18354 Coolant fan
So there it hangs. Customer is going to have the software upgrade and see what happens as far as the NOX sensor is concerned. The Accelerator pedal sensor is going to be replaced. He will live with the coolant fan problem and see what materialises on cylinder 2.
Will let you know of any developements.
Thanks for all your interest and advice. Special thanks to James for the info on the motorised throttle body.
on February 13, 2012, 10:56 pm, in reply to "