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- Jan 26, 2017
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Hi all,
For reference, my car is a 2018 DAZA Sportback with 30k on the clock. Never been mapped or modified.
About a month ago I was stationary for roughly 10 minutes with the car on. There was a small period (around 5 seconds) when the idle felt a bit odd but the car didn't cut out and then idled fine again. When I proceeded to drive off, after going over a steep speed bump at low speed, I got a yellow warning error on the dash reading 'Drive system: fault. Please contact workshop'. The car then proceeded to limit my RPM to a max of 4k. I got to the petrol station, filled up and the warning had gone when I turned the car back on. Even though the warning has gone, the car drives fine but doesn't feel like I'm getting 100% power and is very slow when changing down gears so the issue is clearly still present. At the time I didn't have my OBD scanner so I tried to replicate the issue on my driveway by leaving the car idling for a bit and then driving slowly off but nothing came up. I then went to the same location where it first appeared, sat in the car for about 10 mins, proceeded to drive over the speed bump (it's pretty steep) and lone behold the warning came up again! It read P0087 - Low rail/system pressure.
I took it to a recommended Audi specialist in North London. They found the following faults:
1. Oxygen sensor fault - Bank 1, Senor 2 (had no idea about this one as it never came up when I scanned the car and I never had a check engine light)
2. EVAP Emissions (they said this was related to the o2 sensor issue)
3. Low fuel rail pressure
They recommended I replace both o2 sensors instead of just the faulty one. I asked why as this didn't make much sense to me but apparently having a new o2 sensor and having the paired one being older can cause issues, this can cause the ECU to flag a fault code. If this did happen (I was told it was likely and they've seen this before) they would have to charge me a diagnostic fee again and labor to install the other o2 sensor so I got them done both at the same time. In hindsight, after speaking to an ex Audi tech friend of mine (was on holiday at the time and not responding to messages) I don't think this was necessary and I was probably ok to replace just the faulty sensor.
They also said they thought the o2 sensor was causing the low fuel rail pressure and replacing the o2 sensor should fix that issue too. They cleared the codes, took the car for a drive and said it was all fine. No fault codes appearing (I did mention, the P0087 related error only seems to come up when I have about 30ish miles in the tank and I'm idle for a while then drive off).
The car is still not getting 100% power, feels like it's being limited and the car is still hesitant to change down gears. Even when I come off the throttle, it almost feels like the car is engine braking slightly (I'm guessing this is due to the fuel not being delivered correctly). It seems the low rail pressure issue is still present but it's very difficult to try and get it to appear on the dash. I've read some other threads which look similar (Thread 1) (Thread 2) (Thread 3). Stuck in traffic or idling for long periods of time on lowish fuel and get the same error, looks to be the fuel pump control module on some of the RS3's were fault however these cars were new at the time. Mine is a 2018 model, 30k on the clock. Would the control module suddenly fail now? Also my car isn't stalling or cutting out, it's just limited in power and and sluggish on changing down gears. Changing up is fine.
Apologies, I know I've written a lot, but if you are still reading this, I have a few questions.
1. I understand the fuel filter is not a serviceable item on these RS3s but I've read this could be causing the P0087 issue. Are these located under the rear seats with the low pressure fuel pump? If so, does anyone know the part numbers for this?
2. I'm going to change the fuel pump control module too. I understand this is also under the rear seats. Does anyone know the part number for this too?
3. Is there any other cheaper items I should try replacing myself before sending it to another garage?
4. Does anyone know of any Audi specialists they can recommend around the London area I can send the car to? I don't really want to send it back to the previous Audi specialists as I ended up paying just under £800 to get two oxygen sensors replaced when I probably only needed to do one and I was told a faulty oxygen sensor could also be causing the P0087 code but after doing some research and speaking to another garage, an o2 sensor has nothing to do with low fuel rail pressure and they are not linked.
For reference, my car is a 2018 DAZA Sportback with 30k on the clock. Never been mapped or modified.
About a month ago I was stationary for roughly 10 minutes with the car on. There was a small period (around 5 seconds) when the idle felt a bit odd but the car didn't cut out and then idled fine again. When I proceeded to drive off, after going over a steep speed bump at low speed, I got a yellow warning error on the dash reading 'Drive system: fault. Please contact workshop'. The car then proceeded to limit my RPM to a max of 4k. I got to the petrol station, filled up and the warning had gone when I turned the car back on. Even though the warning has gone, the car drives fine but doesn't feel like I'm getting 100% power and is very slow when changing down gears so the issue is clearly still present. At the time I didn't have my OBD scanner so I tried to replicate the issue on my driveway by leaving the car idling for a bit and then driving slowly off but nothing came up. I then went to the same location where it first appeared, sat in the car for about 10 mins, proceeded to drive over the speed bump (it's pretty steep) and lone behold the warning came up again! It read P0087 - Low rail/system pressure.
I took it to a recommended Audi specialist in North London. They found the following faults:
1. Oxygen sensor fault - Bank 1, Senor 2 (had no idea about this one as it never came up when I scanned the car and I never had a check engine light)
2. EVAP Emissions (they said this was related to the o2 sensor issue)
3. Low fuel rail pressure
They recommended I replace both o2 sensors instead of just the faulty one. I asked why as this didn't make much sense to me but apparently having a new o2 sensor and having the paired one being older can cause issues, this can cause the ECU to flag a fault code. If this did happen (I was told it was likely and they've seen this before) they would have to charge me a diagnostic fee again and labor to install the other o2 sensor so I got them done both at the same time. In hindsight, after speaking to an ex Audi tech friend of mine (was on holiday at the time and not responding to messages) I don't think this was necessary and I was probably ok to replace just the faulty sensor.
They also said they thought the o2 sensor was causing the low fuel rail pressure and replacing the o2 sensor should fix that issue too. They cleared the codes, took the car for a drive and said it was all fine. No fault codes appearing (I did mention, the P0087 related error only seems to come up when I have about 30ish miles in the tank and I'm idle for a while then drive off).
The car is still not getting 100% power, feels like it's being limited and the car is still hesitant to change down gears. Even when I come off the throttle, it almost feels like the car is engine braking slightly (I'm guessing this is due to the fuel not being delivered correctly). It seems the low rail pressure issue is still present but it's very difficult to try and get it to appear on the dash. I've read some other threads which look similar (Thread 1) (Thread 2) (Thread 3). Stuck in traffic or idling for long periods of time on lowish fuel and get the same error, looks to be the fuel pump control module on some of the RS3's were fault however these cars were new at the time. Mine is a 2018 model, 30k on the clock. Would the control module suddenly fail now? Also my car isn't stalling or cutting out, it's just limited in power and and sluggish on changing down gears. Changing up is fine.
Apologies, I know I've written a lot, but if you are still reading this, I have a few questions.
1. I understand the fuel filter is not a serviceable item on these RS3s but I've read this could be causing the P0087 issue. Are these located under the rear seats with the low pressure fuel pump? If so, does anyone know the part numbers for this?
2. I'm going to change the fuel pump control module too. I understand this is also under the rear seats. Does anyone know the part number for this too?
3. Is there any other cheaper items I should try replacing myself before sending it to another garage?
4. Does anyone know of any Audi specialists they can recommend around the London area I can send the car to? I don't really want to send it back to the previous Audi specialists as I ended up paying just under £800 to get two oxygen sensors replaced when I probably only needed to do one and I was told a faulty oxygen sensor could also be causing the P0087 code but after doing some research and speaking to another garage, an o2 sensor has nothing to do with low fuel rail pressure and they are not linked.
