Error code 17559/P1151 with 1.4 petrol AUA Engine

spw

spw

Member
Hi

I'm looking for help in diagnosing an intermittent issue I've had with my 1.4 petrol A2, flagged by the orange engine light being illuminated.
Initially I was getting the fault once every couple of months, , but more recently it is become much more frequent, to the point now that it is occurring almost every other journey I take.

A scan always gives the same code 17559/P1151 Long Term Fuel Trim Additive Air Bank 1: Range 1: System too lean.

Searching through the forums it seems to be a common problem with the 1.4 petrol engine but there seems to be several possible causes and over the months I have been working through them in an effort to fix the fault. Sadly to no avail.

To date over the past 18 months I have tried the following -

Replacement of the coolant temp sensor and front lambda sensor.
EGR valve cleaned and reset, eventually replaced the EGR valve.
Replacement of the little plastic valve on the EGR breather pipe
Several checks for air leaks.
Cleaning and re-setting the throttle body
Replaced the coil pack, spark plugs and leads
Tried running on super unleaded petrol

It used to be that the light nearly always came on shortly after a journey on the motorway, usually as I left the slip road, which made me think it was EGR related, but after replacing the coil pack, spark plugs and leads the light is now coming on at different times, sometimes directly on start up when the car is still warm.

A few other observations -

On tick over the car idles at around 600-700rpm when warm, just over 1000 from cold, which feels a little low.

More recently I've had a couple of occasions where the engine struggled to fire or took longer to start than normal

When cold, there feels to be a very slight miss-fire at between 1000-2000rpm while under load and when warm there feels to be a similar slight miss-fire at between 3000-4000rpm. This was what prompted me to replace the coil, plugs and leads. The car now revs much better, but there still seems to be the slight lumpy-ness in the revs under load.

Its the 1.4 AUA Engine, reguarly serviced every 6-7K miles

I'm now running out of idea's of what to try next and I welcome any suggestions anyone might have for things to try next.

I did think about replacing the fuel filter in case there's a blockage.

Is there more than one temperature sensor ? I've replaced the green coolant sensor but wondered if there were others on the air or fuel?
I've had a couple of doubts about the accuracy of the outside temp reading on the dash, which sometimes looks to be out by a few degrees.

Thanks in advance
 
<bump>

Can anyone out there more technical than myslef please explain which sensors provide measurments to the ECU to control mixture?

Thanks in advance
 
From Rosstech wiki, if you haven't found this yet:


Possible Causes
Intake System faulty/leaking
Fuel Pressure, Fuel Pressure Regulator and Fuel Pump faulty
Fuel Injectors faulty/leaking
Exhaust System faulty/leaking
Activated-Charcoal Filter/System faulty/leaking
Secondary Air Injection System faulty/leaking
Lambda/Oxygen Sensor(s) before Catalytic Converter faulty
Lambda/Oxygen Sensor(s) after Catalytic Converter faulty


Possible Solutions
Check Intake System for Leaks
Check Fuel Pressure, Fuel Pressure Regulator and Fuel Pump
Check Fuel Injectors
Check Exhaust System for Leaks
Check Activated-Charcoal Filter/System
Check Secondary Air Injection System
Check Lambda/Oxygen Sensor(s) before Catalytic Converter
Check Lambda/Oxygen Sensor(s) after Catalytic Converter

Something that comes to my mind would be checking exhaust manifold for leaks/are bolts tight/caskets ok, so the lambda can read right. As for idle problem, how about the idle sensor is it in the throttle body / can it be tested by plugin on/off. After those I would turn to check fuel delivery "chain" issues.
 
Last edited:
Thanks dadomonster

I've had the garage check for leaks in the intake and exhaust a few times now without anything found.

Both Lambda probes have been checked and working fine.

The throttle body was recently removed, cleaned and reset. This made an improvement in the throttle response but this is when I started to notice the feeling of a slight missfire between 1-2000 revs when cold and 3-4000 when at working temperature. The garage didn't raise any concerns with the idle sensor but worth asking them again.

One thing I've noticed is that the rev counter needle sometimes ocilates slightly at idle. It is as if its either compensating or maybe recalibrating.

I've also noticed that it seems to run better when its a cooler outside. Steady idle, nice smooth power delivery.
 
I would recomend some quality injection cleaner as it sounds as if a certain fuel delivery it isn't squirting correctly- hence it's ruff at a lower rpm cold then higher rpm when hot.
Cheers and good luck. Mike
 
hi

Car was back in the garage a couple of weeks ago where they replaced the fuel filter and ran through some injector cleaner.

Most of the time the car is now runing much better, throttle response seems better. Unfortunalty I'm still getting the 17559/P1151 error code. At first I thought it might be down to the injector cleaner still going through the system so on the first occurance I cleared the code and carried on. A couple of weeks later the light is back on. It came on after a short run at the weekend.\

Another development is I have experienced a cople of occurances of the revs being very eratic at idle. The rev's fluctuate between 600 and 800rpm, to the point the car is about to stall and the ECU seems to adjust something to bring it back. This was with the car at working temperature. In the past giving a little more throttle seemed to clear it but not tonight. restarting the car cleared it for a couple of mins. where it reverted to the eratic idle.

I've had regular accurances of slight fluctuations in the revs at idle, which I think is a common with the AUA engine, but this was much more extreame.

Has any body experienced anything similar of might give me soem pointer to check.


Thanks in advance
 
Hi
Wife's A2 is in garage having some repairs but it went in with a management light showing, garage checked it out and it was running lean. Had the throttle housing cleaning as part of the work-to-be-done and it's now running perfect. Management light has not returned. You may have a couple of problems with your car and this may be one of them.
 
Thanks dicko, I've had the throttle body off for cleaning and that did improve the general running but still get the lean error code, usually after a longer run.
 
The cars going in again tommorow to have the throttle body off, cleaned again and reset.

Last time they had it off they reused the original gasket, which reading other posts might cause complications, so I've asked them to change it this time round.
If I think back, the last time they cleaned I did notice a marked improvement in the response, but it was around then I was noticing what I thought to be slight missing during acceleration.

I'm also not convinced by the tick over, which seems quite low at 6-800rpm, so will ask if there's any option to increase it in the software. When coming off the throttle I've seen the revs drop below this and then bounce back to the low idle, which I'm sure is not right and makes it hard to get it off the line smoothly.

Fingers crossed this sorts it out.
 
I know this was long ago but I wonder if you manage to sort it out as I have the same problem the only difference is that I get the EML and EPC on as soon as I start the engine and I get the same error as yours 17559.
Thanks!
 
What have you done to try and fix it Dimitar? I would suggest start cleaning the throttle body, replace the gasket and reset it with VCDS.
 
There is no leak around the throttle body and it's clean to. Year ago i done a full service off the car + new Front O2 sensor (oem) and spark plugs + cables.
 
In case language is causing misinterpretation, Gustav is referring to cleaning the inside of the Throttle body.
 
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