P256300, P000B00, P256500, 00458, 03705 Fault Advice

[Dion17]

Hello All,

Currently experiencing the following codes appear on my B8.5 A5 2L TFSI
P256300 - Turbocharger Boost Control Position Sensor Circuit Range/Performance (Passive/Sporadic)
P000B00 - 'B' Camshaft Position Slow Response (Bank 1) (Passive/Sporadic)
P256500 - Turbocharger Boost Control Position Sensor Circuit High (Passive/Sporadic)
00458 - Battery Monitoring Control Module - No signal/communication (Active/Static)
03705 - Voltage Stabilizer - No Signal/Communication (Active/Static)

Any suggestions on the probable cause? Are they linked? Car drives fine for 3-5km before the EPC light comes on. Turning the car off and on takes the light away for another 3-5kms. Note the start/stop feature does not seem to work either. After driving long enough. "Start/Stop System Fault" will appear on the dash.

Any help will be appreciated

 

[pelhamsdetailing]

Looks like your turbo actuator is on its way out. As for P000B00, what engine do you have? If it's a 3.0TDI, that would probably be a swirl flap motor. If it's any other engine, i'm out of my depth there.

 

[Dippy]

When a battery is near the end of its life it can result in unrelated error codes. The fact that you have a battery related code leads me to suggest that you should rule that out first. How old is your battery?

 

[Dion17]

Looks like your turbo actuator is on its way out. As for P000B00, what engine do you have? If it's a 3.0TDI, that would probably be a swirl flap motor. If it's any other engine, i'm out of my depth there.

My engine is a 2.0 TFSI… will try to look into the actuator. Is there any tests todo before taking the knock and getting a new one ?

 

[Dion17]

When a battery is near the end of its life it can result in unrelated error codes. The fact that you have a battery related code leads me to suggest that you should rule that out first. How old is your battery?

I’ve actually just had the battery replaced 2 days ago however had not had the time to get the battery management system reset as I live in a remote area. Could resetting it have a positive effect?

 

[pelhamsdetailing]

I recently learned that coding the new battery into the ECU helps maintain the correct amount of voltage being put back into the battery itself, via the alternator. As a battery gets older and older, a higher charge is put into the battery. Also, having put a new battery in, it could have simply caused the last two fault codes to appear simply from a sudden loss of power. If you have a car scanner of any kind, either via an OBD2 device/dongle and an app/software, then you can clear your ECU's codes and see if they return. If your car does indeed require coding of a new battery, then that can be done via a garage. You'd be paying more for the labour than the effort of plugging in their device and pressing a few buttons.

I take back my mention of a turbo actuator on the engine as I've just realised this car does not have one. It does have a Turbocharger Boost Control Position Sensor, as mentioned in your fault code above, which does exactly what it says on the tin. This seems faulty judging by the two fault codes, which would mean a straight swap of said part. These are plug and play and shouldn't require any learning/adaption done via software. However, software will be required to clear the fault codes you have from your ECU once you've replaced this sensor.

The cam shaft position response could be the result of the boost sensor playing up, but i'm not too familiar with this engine in that I know whether the camshaft is variable or not.

 

[Dippy]

I agree with @Vappy which means that you probably do have a real problem or two if you have a cam adjuster issue as well as boost sensor. I can't quite see how they can be related. Start/stop has many prerequisites to activate so could easily be disabled by a fault which affects emissions and/or efficiency.

 

[46lukasz]

I just solved faults 00458, 03705 in my car. Take a look at my thread:

Fault codes about battery voltage and air quality sensor

Hello, I have 4 fault codes in my 2016 A5 2.0 TDI that keep coming back periodically after clearing. I am scanning using OBDeleven so may not be as accurate as VCDS but here is the information The car is running fine and they don't really affect me but i would like them to not be there...

www.audi-sport.net