hallo, today i made a diagnose to my ford cmax 2009 125ps 1.8L,i used obd2 with forscanthen i have got this

===PCM DTC P0171-E3===
Code: P0171 - System Too Lean Bank 1

Additional Fault Symptom (:03):
 - Signal is Above Maximum Threshold

Status (-E0):
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is On for this DTC

Module: Powertrain Control Module

Diagnostic Trouble Code details

System Too Lean Bank 1

Fuelling adaptation is above the maximum limit.

This DTC may be caused by :

Air leaks at the intake manifold

Low fuel pressure.

===END PCM DTC P0171-E3===

any help please

Have you looked for vacuum leaks around the inlet as it suggests?

19 minutes ago, TomsFocus said:

Have you looked for vacuum leaks around the inlet as it suggests?

thankyou for your replay. no, i didn't looked again but i will do it, in some sites they talked about Maf sensor and O2 sensor but i don't have any idea where is the location of these sensors

1 hour ago, max2019 said:

thankyou for your replay. no, i didn't looked again but i will do it, in some sites they talked about Maf sensor and O2 sensor but i don't have any idea where is the location of these sensors

The O2 sensor is in the exhaust manifold.  That is telling us the mixture is lean.  But I don't think the sensor is faulty from that code.

This engine doesn't have a MAF sensor fitted.

On 11/7/2025 at 6:55 PM, TomsFocus said:

The O2 sensor is in the exhaust manifold.  That is telling us the mixture is lean.  But I don't think the sensor is faulty from that code.

This engine doesn't have a MAF sensor fitted.

hallo, thankyou for your answer, my car doesn't have a MAF sensor fitted? this means has a MAP sensor i think. what could be the fault of that code?

6 minutes ago, max2019 said:

what could be the fault of that code?

A vacuum leak around the inlet.

29 minutes ago, TomsFocus said:

A vacuum leak around the inlet.

i already looked to the hoses around the inlet , i tkink they fit gut.yes of course the hoses that i can see 

53 minutes ago, max2019 said:

s has a MAP sensor i think. what could be the fault of that code?

If your MAP Sensor was faulty there would be a different code.

8 minutes ago, Tizer said:

If your MAP Sensor was faulty there would be a different code.

thankyou for your answer. what can be the problem?

hello everyone, my car drives with petrol/gas , i used the smoke machine to detect any leak,then it leaks as you see in the pic.can anyone tell me what is the name of this thing under the hoses ?sorry that i uploaded many pictures 

 

8 minutes ago, max2019 said:

hello everyone, my car drives with petrol/gas , i used the smoke machine to detect any leak,then it leaks as you see in the pic.can anyone tell me what is the name of this thing under the hoses ?sorry that i uploaded many pictures 

 

That is the EGR valve.  They are known for cracking as they get older.

Ford EGR Valve ST150 Fiesta, Focus, 2.0 Duratec - 5204549 / 1S7G-9D475-AK | eBay UK

23 minutes ago, TomsFocus said:

That is the EGR valve.  They are known for cracking as they get older.

Ford EGR Valve ST150 Fiesta, Focus, 2.0 Duratec - 5204549 / 1S7G-9D475-AK | eBay UK

thank you for your quick response 👍

i would like to replace this part.i don't have any idea if has something to do with the gas system

24 minutes ago, max2019 said:

thank you for your quick response 👍

i would like to replace this part.i don't have any idea if has something to do with the gas system

Not part of the gas or petrol system.  It is part of the air intake system.  It does also have a coolant pipe to keep it water-cooled, so need to expect a bit of coolant loss if changing it yourself.

57 minutes ago, TomsFocus said:

Not part of the gas or petrol system.  It is part of the air intake system.  It does also have a coolant pipe to keep it water-cooled, so need to expect a bit of coolant loss if changing it yourself.

can i replace it? what do you think about these hoses that are over the valve?

4 minutes ago, max2019 said:

can i replace it? what do you think about these hoses that are over the valve?

I don't know what your skill set is.  The valve can definitely be replaced.  But I can't guarantee that you would be able to replace it yourself.  The job is quite easy on petrol-only cars.  But the LPG on yours might make it more difficult.

The pipes right on top of the valve are for petrol and vacuum.  The gas pipes are slightly further over but may still need to be moved.  They should all be possible to remove from clips and push away without disconnecting or opening the pipes at all.   If you're concerned about touching the fuel system, I would recommend asking for a garage/workshop quote to replace.  If it's cheap enough, just let them do it.

25 minutes ago, TomsFocus said:

I don't know what your skill set is.  The valve can definitely be replaced.  But I can't guarantee that you would be able to replace it yourself.  The job is quite easy on petrol-only cars.  But the LPG on yours might make it more difficult.

The pipes right on top of the valve are for petrol and vacuum.  The gas pipes are slightly further over but may still need to be moved.  They should all be possible to remove from clips and push away without disconnecting or opening the pipes at all.   If you're concerned about touching the fuel system, I would recommend asking for a garage/workshop quote to replace.  If it's cheap enough, just let them do it.

i went to the mechanic yesterday.i mean the day before  he told me he can't work on the car because it has this gas system installed. i must to look for a garage for gas system

i really appreciate the help you gave me and your kindness🥰