Fuel Pressure fault p1025
Thread Starter
Racer
Joined: Aug 2021
Posts: 323
Likes: 49
From: New Haven CT
Fuel Pressure fault p1025
My Macan is a 2015 Macan S.
I'm getting a p1025 fault code which activates the check engine light. I cleared it a couple of weeks ago, but it's back again. The fault has something to do with fuel pressure. The car drives perfectly, idles perfectly, and has plenty of power. So, there are no symptoms associated with the fault other than the check engine light. Coincidentally, the fault first appeared the day after my water pump developed a giant leak that resulted in steam filling the engine bay. I'm not sure how that could be related to fuel pressure sensing, though.
I have read about people replacing the high pressure fuel pumps on top of the engine and also the fuel pump in the gas tank. I'd rather not throw parts at the problem. Maybe I could test the fuel pressure, but not sure what else I could do. Hopefully some people here can provide some advice. Thanks.
I'm getting a p1025 fault code which activates the check engine light. I cleared it a couple of weeks ago, but it's back again. The fault has something to do with fuel pressure. The car drives perfectly, idles perfectly, and has plenty of power. So, there are no symptoms associated with the fault other than the check engine light. Coincidentally, the fault first appeared the day after my water pump developed a giant leak that resulted in steam filling the engine bay. I'm not sure how that could be related to fuel pressure sensing, though.
I have read about people replacing the high pressure fuel pumps on top of the engine and also the fuel pump in the gas tank. I'd rather not throw parts at the problem. Maybe I could test the fuel pressure, but not sure what else I could do. Hopefully some people here can provide some advice. Thanks.
Thread Starter
Racer
Joined: Aug 2021
Posts: 323
Likes: 49
From: New Haven CT
The code came back yesterday. So, it came back after about a week and 200 miles.
My icarsoft scan tool gave me some live data while idling in the driveway. I'm not if these fuel values point to anything awry.
Long Term Fuel Trim B1 11.7%
Long Term Fuel Trim B2 9.4%
Short Term Fuel Trim B1-S2 99.2%
Short Term Fuel Trim B2-S2 99.2%
Fuel Rail Pressure 1740psi
Thanks for your help.
My icarsoft scan tool gave me some live data while idling in the driveway. I'm not if these fuel values point to anything awry.
Long Term Fuel Trim B1 11.7%
Long Term Fuel Trim B2 9.4%
Short Term Fuel Trim B1-S2 99.2%
Short Term Fuel Trim B2-S2 99.2%
Fuel Rail Pressure 1740psi
Thanks for your help.
Burning Brakes
Joined: Dec 2021
Posts: 899
Likes: 526
I would measure the pressure on the Low Pressure input hose to the High Pressure Fuel Pump.
If low, check the Low Pressure Fuel Pump, or the Control / Drive Module for the Low Pressure Pump, or a clogged low pressure fuel filter/screen.
If the Low Pressure pressure is within specs, see if the output of the Low Pressure Sensor (Live Data values) agrees with the gauge measurement of the above step. If not, replace the Low Fuel Pressure Sensor.
If the above is OK, try replacing the High Pressure Fuel Sensor.
If the problem persists, replace the High Pressure Fuel Pumps.
From the Workshop Manual:
P1025
Diagnostic information DME (DFI) control unit
Fuel high pressure adaptation
INFORMATION
Faults in the fuel highpressure injection system area are frequently caused by defects in the
predelivery circuit (fuel low pressure).
Therefore, the predelivery circuit must be checked first in case of problems in the area of the
fuel highpressure injection system.
Diagnostic conditions
Engine speed 450 .... 4,000 rpm
Engine temperature 10 ... +100 °C (14 … 212 °F)
Driving with different operating conditions
Possible fault causes
Predelivery quantity or pressure in the fuel lowpressure circuit too low
Fuel highpressure adaptation required (See K 2)
Fuel highpressure pump faulty
INFORMATION 2
The old values must be deleted prior to a new adaptation of the fuel highpressure ranges.
The fuel highpressure adaptation values can be deleted using >PIWIS Tester II< as follows:
>DME< A >Maintenance/repairs< A >Delete adaptation values
If low, check the Low Pressure Fuel Pump, or the Control / Drive Module for the Low Pressure Pump, or a clogged low pressure fuel filter/screen.
If the Low Pressure pressure is within specs, see if the output of the Low Pressure Sensor (Live Data values) agrees with the gauge measurement of the above step. If not, replace the Low Fuel Pressure Sensor.
If the above is OK, try replacing the High Pressure Fuel Sensor.
If the problem persists, replace the High Pressure Fuel Pumps.
From the Workshop Manual:
P1025
Diagnostic information DME (DFI) control unit
Fuel high pressure adaptation
INFORMATION
Faults in the fuel highpressure injection system area are frequently caused by defects in the
predelivery circuit (fuel low pressure).
Therefore, the predelivery circuit must be checked first in case of problems in the area of the
fuel highpressure injection system.
Diagnostic conditions
Engine speed 450 .... 4,000 rpm
Engine temperature 10 ... +100 °C (14 … 212 °F)
Driving with different operating conditions
Possible fault causes
Predelivery quantity or pressure in the fuel lowpressure circuit too low
Fuel highpressure adaptation required (See K 2)
Fuel highpressure pump faulty
INFORMATION 2
The old values must be deleted prior to a new adaptation of the fuel highpressure ranges.
The fuel highpressure adaptation values can be deleted using >PIWIS Tester II< as follows:
>DME< A >Maintenance/repairs< A >Delete adaptation values
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2nd Gear
Joined: Sep 2025
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@secondchris Did you get this resolved? If so what was the culprit? I'm experiencing the same thing with my macan.
Thread Starter
Racer
Joined: Aug 2021
Posts: 323
Likes: 49
From: New Haven CT
Unfortunately, I haven't resolved the fault. The car drives perfectly and I don't have time or money to spend on the car right now. I am managing the fault by clearing the code every 1-2 weeks with my scantool. I have done this about 20 times so far, so I guess it is a "real" fault. Maybe I need to do a readaptation or something but I don't think I have the tool to do that.
2nd Gear
Joined: Sep 2025
Posts: 2
Likes: 0
Ok thank you for the followup. I cleared it yesterday, so we will see when it comes back. My buddy has a tablet that can do a readaption, so if that works, I'll update. Otherwise I'll try cleaning the sensors and see if that helps.
1st Gear
Joined: Jan 2026
Posts: 1
Likes: 0
Any updates ?
Trying to figure out this thing for me too here. Weather or temperature doesn’t not seem to influence fault occurring or at least I know how to trigger it. Low load around 80-100kmh on 7th gear. Did some research on cam timing.. values looks the same on a good working engine. First Gff part cause could be the timing chain or timing.. engine was out and disassembled in 2021. Car is not under warranty (fuel pumps on other vehicule with CPO coverage (low and high) was already replaced and issue came back ) so still did not the find the root of the problem
Thread Starter
Racer
Joined: Aug 2021
Posts: 323
Likes: 49
From: New Haven CT
I don't have any updates and have not been able to resolve the code. I'm currently not using the vehicle, so it's not something I'm concerned about, but I will be putting it back on the road sometime in the future.
Intermediate
Joined: Jan 2024
Posts: 25
Likes: 2
From: Columbus, OH