SAI Insufficient Flow flow errors driving me mad.

[viceroy1976]

I recently bought a 2013 S6, and since it's been getting colder in the mornings, I've been getting SAI insufficient flow errors on both banks.
Scanning the car shows 2 errors as seen below:

I've read through similar threads, and checked the pipes are properly connected as per those threads, but still getting the error.
I did try trace the pipe further towards the left side of the car, and it seems to lead to a bulbous object. Where the pipe is securely connected, but wobbles a bit (Highlighted by red). My next step is to try seal this better with a bit of tape to test if the errors go away, but I'm curious. Is the bulbous object the SAI pump (Highlighted by orange)?

Address 01: Engine (------CEUC)       Labels:. 06E-907-551-CGW.clb
   Part No SW: 4G0 906 014     HW: 4H0 906 014 
   Component: 4.0l V8TFSI / X62 0012  
   Revision: NCX62---    
   Coding: 0A2500326526010A0000
   Shop #: WSC 55167 002 1048576
   ASAM Dataset: EV_ECM40TFS0114G0906014 001014
   ROD: EV_ECM40TFS0114G0906014.rod
   VCID: 5FCB1B3B46CFB2B284-800A

2 Faults Found:
7656 - Secondary Air Injection System: Bank 2 
          P0492 00 [101] - Insufficient Flow
          Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 89828 km
                    Date: 2019.05.18
                    Time: 09:12:05

                    Engine speed: 934.00 /min
                    Normed load value: 16.5 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 27 �C
                    Intake air temperature: 25 �C
                    Ambient air pressure: 860 mbar
                    Voltage terminal 30: 13.122 V
                    Unlearning counter according OBD: 40
                    AFS dm: 48.6 kg/h
                    Median injection timing: 1.234 ms
                    Engine operating condition: Idling
                    Engine operating condition-Test_Program_Channel 87: 5
                    Brake actuated status-Bits 0-7: 144
                    Tumg: 18.8 �C
                    Psr w: 508.05 hPa
                    Engine torque: 100.5 Nm

7654 - Secondary Air Injection System: Bank 1 
          P0491 00 [101] - Insufficient Flow
          Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 89828 km
                    Date: 2019.05.18
                    Time: 09:12:05

                    Engine speed: 934.00 /min
                    Normed load value: 16.5 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 27 �C
                    Intake air temperature: 25 �C
                    Ambient air pressure: 860 mbar
                    Voltage terminal 30: 13.122 V
                    Unlearning counter according OBD: 40
                    AFS dm: 48.6 kg/h
                    Median injection timing: 1.234 ms
                    Engine operating condition: Idling
                    Engine operating condition-Test_Program_Channel 87: 5
                    Brake actuated status-Bits 0-7: 144
                    Tumg: 18.8 �C
                    Psr w: 508.05 hPa
                    Engine torque: 100.5 Nm

Readiness: 0000 1000

Thanks.

[viceroy1976]

Some googling, and I found a picture of the SAI pump on ECS.
Looks like the highlighted part, so will try get the pipe to seal better with tape, and if that fixes the issue, I'll work on a more permanent solution.

[ApostolSauce]

unplug the air hose and feel if your pump is pumping at cold start for starters

[DocTJ]

keep us updated please

[viceroy1976]

Got out my trusty ol' VCDS last night and did some basic output testing.
Pump runs fine.
Solenoid seems to run fine (I can hear it clicking).
Sensor appears to run fine, as in it picks up changes in flow as the pump starts and stops running.
While the pump is running, I cannot hear any obvious leaks.

I still have to test if the pump runs on cold start. Wanted to check this morning, but totally forgot. Will try remember again tomorrow.

In the meantime, does anyone know what the correct flow should be while the pump is running? Knowing this will help me rule out that the sensor is under reading flow.

[gk1]

I don't know the correct flow but here are some resistance values to check the solenoid valve and motor a bit more if you wanted.

• DISCONNECT: Secondary Air Injection Solenoid Valve 2 - N320- connector
• CHECK: Secondary Air Injection Solenoid Valve 2 - N320- component terminals 1 to 2 for resistance.
• SPECIFIED VALUE: 20 to 35 Ω (at approx. 20°C)

• CHECK: Secondary Air Injection Pump Motor- V101- connector terminal 1 to ground. for resistance
• CHECK: Secondary Air Injection Pump Motor- V101- connector terminal 2 to Secondary Air Injection Pump Relay - J299- terminal 5 for resistance.
• SPECIFIED VALUE: 0.5 Ω ( ± 0.3 Ω )

• REMOVE: Engine Control Module - J623- .Refer to the appropriate repair manual.
• CHECK: Secondary Air Injection Pump Relay- J299- connector terminal 2 to Engine Control Module - J623- connector terminal T91 / 54 for resistance
• SPECIFIED VALUE: 0.5 Ω ( ± 0.3 Ω )

These are the only other values I could find, but not sure if they are what you are looking for.

$82 P0492
Examination secondary air system, reduced secondary air mass. Bank 2
Min 0.102
Max 1.999

$83 System testing, reducing secondary air mass, switching phase. Bank 2
Min 0.703
Max 1.999

$84 System testing, leak detection behind valve (diagnosis result FAIL). Bank 2
Min (1.367 -11.523 kPa)
Max 32.767 kPa

Also it gives the malfunction criteria and threshold values: (If that helps)

• blockage: relative AIR pressure measured with AIR pressure sensor vs. modeled <0.10 [-]
• leakage: relative AIR pressure measured with AIR pressure sensor vs. modeled <0.10 [-]
• and relative AIR pressure measured <= 3.00 kPa
• or blockage: relative AIR pressure measured with AIR pressure sensor vs. modeled <0.45 [-]
• leakage: relative AIR pressure measured with AIR pressure sensor vs. modeled <0.45 [-]
• and relative AIR pressure measured <=3.00 kPa
• or blockage: relative AIR pressure measured with AIR pressure sensor vs. modeled while valve bank 2 commanded closed < 0.70[-]
• leakage: relative AIR pressure measured with AIR pressure sensor vs. modeled while valve bank 2 commanded closed < 0.70[-]
• and relative AIR pressure measured <=3.00 kPa
• or average pressure difference between absolute value and filtered value while valve bank 2 commanded closed < 0.14- 1.22 kPa
• and relative AIR pressure measured <=3.00 kPa

Hope that helps.

[viceroy1976]

I don't know the correct flow but here are some resistance values to check the solenoid valve and motor a bit more if you wanted.

• DISCONNECT: Secondary Air Injection Solenoid Valve 2 - N320- connector
• CHECK: Secondary Air Injection Solenoid Valve 2 - N320- component terminals 1 to 2 for resistance.
• SPECIFIED VALUE: 20 to 35 Ω (at approx. 20°C)

• CHECK: Secondary Air Injection Pump Motor- V101- connector terminal 1 to ground. for resistance
• CHECK: Secondary Air Injection Pump Motor- V101- connector terminal 2 to Secondary Air Injection Pump Relay - J299- terminal 5 for resistance.
• SPECIFIED VALUE: 0.5 Ω ( ± 0.3 Ω )

• REMOVE: Engine Control Module - J623- .Refer to the appropriate repair manual.
• CHECK: Secondary Air Injection Pump Relay- J299- connector terminal 2 to Engine Control Module - J623- connector terminal T91 / 54 for resistance
• SPECIFIED VALUE: 0.5 Ω ( ± 0.3 Ω )

These are the only other values I could find, but not sure if they are what you are looking for.

$82 P0492
Examination secondary air system, reduced secondary air mass. Bank 2
Min 0.102
Max 1.999

$83 System testing, reducing secondary air mass, switching phase. Bank 2
Min 0.703
Max 1.999

$84 System testing, leak detection behind valve (diagnosis result FAIL). Bank 2
Min (1.367 -11.523 kPa)
Max 32.767 kPa

Also it gives the malfunction criteria and threshold values: (If that helps)

• blockage: relative AIR pressure measured with AIR pressure sensor vs. modeled <0.10 [-]
• leakage: relative AIR pressure measured with AIR pressure sensor vs. modeled <0.10 [-]
• and relative AIR pressure measured <= 3.00 kPa
• or blockage: relative AIR pressure measured with AIR pressure sensor vs. modeled <0.45 [-]
• leakage: relative AIR pressure measured with AIR pressure sensor vs. modeled <0.45 [-]
• and relative AIR pressure measured <=3.00 kPa
• or blockage: relative AIR pressure measured with AIR pressure sensor vs. modeled while valve bank 2 commanded closed < 0.70[-]
• leakage: relative AIR pressure measured with AIR pressure sensor vs. modeled while valve bank 2 commanded closed < 0.70[-]
• and relative AIR pressure measured <=3.00 kPa
• or average pressure difference between absolute value and filtered value while valve bank 2 commanded closed < 0.14- 1.22 kPa
• and relative AIR pressure measured <=3.00 kPa

Hope that helps.

Thanks very much for this. I'm sure if I need to start digging deeper into this issue, these values will be very helpful.

[viceroy1976]

I was just poking around in the engine bay again, and I noticed that the pipe leading to the round bulbous object next to the coolant reservoir is quite loose.
To my knowledge (mostly gained from this document), this is a vacuum reservoir, and I would guess should be sealed in order to maintain a vacuum.
So a loose pipe, would not allow vacuum, and the combi valves would not be able to operate, and why I'm getting issue.
Another thing to test tomorrow.

[viceroy1976]

Issue is resolved.
Vacuum pipe into the vacuum reservoir was loose. Automotive silicone to reseal it and no more errors.

Sent from my MI 8 using Tapatalk

[gk1]

Issue is resolved.
Vacuum pipe into the vacuum reservoir was loose. Automotive silicone to reseal it and no more errors.

Sent from my MI 8 using Tapatalk

Nice. Glad you found it and posted the fix. Thanks.

[15 Phantom S6]

Issue is resolved.
Vacuum pipe into the vacuum reservoir was loose. Automotive silicone to reseal it and no more errors.

Sent from my MI 8 using Tapatalk

Any idea why or how it came loose to begin with? Any pics of your fix?

[viceroy1976]

Any idea why or how it came loose to begin with? Any pics of your fix?

My resevoir is missing the inner pipe completely. Guessing it was broken off at some point in the past and the vacuum line was just glued in place with some kind of glue.

The fix is temporary while I wait for a replacement resevoir.

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