+10% load = PCV error, Knock sensor bank 1&2, Secondary Air Injection System Bank 1&2

[96Racing]

Howdy, any wisdom about root cause of my mystery problem that is growing in # of error codes?

My 2017 Audi SQ5 (B8) has just over 63k miles on the clock.

Accelerating with more than 10% throttle caused immediate CEL -> To begin with I only received PCV valve error, then random misfire came shortly after.

At that point I pulled compressor to inspect, noticed intercooler leak with coolant residue in the intake -> did a major service to replace:
PCV assembly + the TSB about the little boot on the vacuum line next to it.
Also replaced both intercoolers, cleaned intake from coolant residue buildup, 6 new spark plugs, new water pump, new belt and new pulley/tensioner.

No more misfires after that, but the PCV error keeps coming back under acceleration more than 10% throttle, then it started adding intermittent knock sensor errors, and yesterday I now also got Secondary Air Injection System error codes as well.

Carefully inspected the plastic pipes under the compressor, they looked good, but those pipes are known to fail, so certainly keeping them in mind.

*** Found out today that the PCV error comes in separate from the other errors and doesn't trigger CEL light on dash ***


Exec summary:
PCV error + Knock sensor 2 + Secondary Air Injection System: Bank 1 & 2:


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Error Code Summary
20136 - PCV Valve Malfunction - P052E 00 [01101101] - Confirmed - Tested Since Memory Clear

9542 - Knock Sensor 2 (G66) - P0332 00 [11101100] - Signal too Low

9544 - Knock Sensor 2 (G66) - P0331 00 [01100000] - Implausible Signal

17619 - Secondary Air Injection System: Bank 1 - P0491 00 [01100000] - Insufficient Flow

17620 - Secondary Air Injection System: Bank 2 - P0492 00 [01100000] - Insufficient Flow


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Full VAG-COM details:

5 Faults Found:
17619 - Secondary Air Injection System: Bank 1
P0491 00 [01100000] - Insufficient Flow
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 102214 km
Date: 2024.10.12
Time: 12:25:11

Engine RPM: 1866.00 /min
Normed load value: 14.1 %
Vehicle speed: 16 km/h
Coolant temperature: 19 °C
Intake air temperature: 23 °C
Ambient air pressure: 830 mbar
Voltage terminal 30: 12.593 V
Unlearning counter according OBD: 37
Engine speed: actual: 1856 /min
MAF_ENVD: 217.88235 mg/stroke
Coolant temperature (unfiltered): 19.50 °C
Engine: operating status: PL
Battery voltage: 12.593750 V
STATE_LS_ENVD[1]: 2

17620 - Secondary Air Injection System: Bank 2
P0492 00 [01100000] - Insufficient Flow
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 102214 km
Date: 2024.10.12
Time: 12:25:11

Engine RPM: 1866.00 /min
Normed load value: 14.1 %
Vehicle speed: 16 km/h
Coolant temperature: 19 °C
Intake air temperature: 23 °C
Ambient air pressure: 830 mbar
Voltage terminal 30: 12.593 V
Unlearning counter according OBD: 37
Engine speed: actual: 1856 /min
MAF_ENVD: 217.88235 mg/stroke
Coolant temperature (unfiltered): 19.50 °C
Engine: operating status: PL
Battery voltage: 12.593750 V
STATE_LS_ENVD[1]: 2

20136 - PCV Valve Malfunction
P052E 00 [01101101] - -
Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 2
Mileage: 101988 km
Date: 2024.10.07
Time: 09:20:08

Engine RPM: 705.00 /min
Normed load value: 12.2 %
Vehicle speed: 0 km/h
Coolant temperature: 94 °C
Intake air temperature: 35 °C
Ambient air pressure: 830 mbar
Voltage terminal 30: 14.319 V
Unlearning counter according OBD: 40
Engine speed: actual: 704 /min
MAF_ENVD: 163.41176 mg/stroke
Coolant temperature (unfiltered): 94.50 °C
Engine: operating status: IS
Engine load: 13.281250 %
Vehicle speed: actual: 0 km/h

9542 - Knock Sensor 2 (G66)
P0332 00 [11101100] - Signal too Low
MIL ON - Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 4
Mileage: 102083 km
Date: 2024.10.09
Time: 09:24:44

Engine RPM: 2879.00 /min
Normed load value: 73.3 %
Vehicle speed: 39 km/h
Coolant temperature: 94 °C
Intake air temperature: 36 °C
Ambient air pressure: 840 mbar
Voltage terminal 30: 12.695 V
Unlearning counter according OBD: 40
Engine speed: actual: 2880 /min
MAF_ENVD: 234.22352 mg/stroke
Coolant temperature (unfiltered): 95.25 °C
Engine: operating status: PL
Engine load: 15.625000 %
Vehicle speed: actual: 57 km/h

9544 - Knock Sensor 2 (G66)
P0331 00 [01100000] - Implausible Signal
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 8
Mileage: 102066 km
Date: 2024.10.09
Time: 09:01:20

Engine RPM: 2419.00 /min
Normed load value: 58.8 %
Vehicle speed: 61 km/h
Coolant temperature: 94 °C
Intake air temperature: 39 °C
Ambient air pressure: 840 mbar
Voltage terminal 30: 14.015 V
Unlearning counter according OBD: 37
Engine speed: actual: 2880 /min
MAF_ENVD: 512.02352 mg/stroke
Coolant temperature (unfiltered): 96.75 °C
Engine: operating status: PL
Engine load: 35.156250 %
Vehicle speed: actual: 73 km/h

Readiness: 0000 0100

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[Discipulus]

Any chance one of the plastic pipes under the supercharger cracked? Or the Y-pipe that goes from the PCV to each valve cover?

Sent from my Pixel 7 Pro using Audizine Forum mobile app

[96Racing]

[QUOTE=Discipulus;15110843]Any chance one of the plastic pipes under the supercharger cracked? Or the Y-pipe that goes from the PCV to each valve cover?


Carefully inspected the plastic pipes, they looked good, but those pipes are known to fail so keeping them in mind.

Found out today that the PCV error comes in separate from the other errors and doesn't trigger CEL light on dash.

[LowKeyLoki]

For the knock sensor code, did you have to remove your knock sensor when you replaced the PCv? They are torque sensitive and if they aren’t torqued back properly will def cause knock codes, that or it’s not plugged in all the way or damage to the wiring.

[NikolaZ]

I am having exactly the same issues: PCV and Knock Sensor 2. I really hope that the cores of the supercharger won't be busted. The error for the pcv comes from the breather tube with the valve.

I will leave the car on monday inthe shop and see what will be the verdict.

[NikolaZ]

Update, yep one of the cores is cracked, will have to change them after new year…

Can confirm that the missfires are still there even with changed sensor, bolt and tensioned properly.

I will not drive the car until new year. Will see how much will be the supercharger cores and I might just swap supercharger with another one if it is cheaper

[Discipulus]

Update, yep one of the cores is cracked, will have to change them after new year…

Can confirm that the missfires are still there even with changed sensor, bolt and tensioned properly.

I will not drive the car until new year. Will see how much will be the supercharger cores and I might just swap supercharger with another one if it is cheaper

Sooooo gonna go with a ported blower? You gotta pull the old one off and remove the cores anyway...

[NikolaZ]

Nah, there is one guy in my home town running on his 3rd engine and he saved my ass yesterday, the fuel lines thread was worn and couldn’t tighten it. That guy brought fuel lines to the mechanic. So he has 2 chargers sitting around and if they are cheaper well I might just get one off of his hands 😄