0491 SECONDARY AIR SYSTEM (BANK 1) FAULT CODE 2001 AUDI A8L

codes p 0410, 0411, 0412 all refer to the secondary air injection system--malfunction, incorrect flow detected and circuit malfunction ===causes are --wiring--sir valve---air solenoid--ECM--air pump, air hose/s--ECM
code p 0491 refers to secondary air injection bank 1 --malfunction or insufficient flow=== causes are the same with a mechanical fault added
so to analyze -- the most common cause is air hoses, followed by valve or solenoid of the air injection system followed by ECM which be as little as a bad pin connection in the wiring

P1421 Secondary Air System Bank 1 P1422 Secondary Air System Bank 2

Read more at: http://www.obd-codes.com/trouble_codes/bmw/
Copyright © OBD-Codes.com

here is what i found on p1416.



P1416 Chevrolet
P1416 Chevrolet - Secondary Air Injection System Bank 2
Possible causes
- Faulty Secondary Air Injection (AIR) pump
- Secondary Air Injection check valve bank 2
- Secondary Air Injection (AIR) pump electrical circuit fault
- Blocked Secondary Air Injection (AIR) system

When is the code detected?

The P1416 code is set when no O2 sensor voltage change is detected by the Engine Control Module (ECM).


Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)


P1416 Chevrolet Description
An Secondary Air Injection (AIR) pump is used on this vehicle to lower tail pipe emissions on start-up. The PCM supplies a ground to the AIR pump relay, which energizes the AIR pump. The Powertrain Control Module (PCM) monitors the HO2S voltages to diagnose the AIR system. During the AIR test the PCM activates the AIR pump during closed loop operation. When the AIR is activated, the PCM monitors the HO2S voltages and short term fuel trim values for both banks of the engine. If the AIR system is operating properly, the HO2S voltages should go low and the short term fuel trim should go high.

P0491 Secondary Air Injection System (Bank 1)
P0492 Secondary Air Injection System (Bank 2)
Good luck for you!
OBD2 code reader

CODE P1128 LONG TERM FUEL TRIM ADD BANK 1 SYSTEM TOO LEAN CONDITIONS.SOUND LIKE YOU HAVE WEAK FUEL PRESSURE.FUEL PRESSURE SHOULD BE WITH NEW FUEL FILTER 36 PSI FOR THE ENGINE CODE AMU. AND FOR ENGINE CODE AEB 50 - 58 FAULTY MAF SENSOR.CLEAN FUEL INJECTORS THEY COULD BE CLOGGED CAUSE LEAN FUEL CONDITIONS,FAULTY SECONDARY AIR INJECTION SYSTEM COMBINATION VALVE STUCK OPEN OR SECONDARY AIR INJECTION SYSTEM HAS A ELECTRICAL SHORT OR ECM CONTROL FAULT.CHECK FOR INTAKE MANIFOLD VACUUM LEAKS. CHECK ALL VACUUM HOSES ON THE INTAKE.

Firing order for 2003 (B6) Audi S4 4,2l V8 engine is: 1 - 5 - 4 - 8 - 6 - 3 - 7 - 2
Cylinder no.# 1 is first one from right front side of the car, and cylinder no.# 4 is the fourth one (front to rear) on the right bank of cylinder block. See picture below:

2001 Audi A6
EOBD code: P0420
Fault location: Catalytic converter system, bank 1 - efficiency below threshold
Probable cause: Catalytic converter, wiring, heated oxygen sensor 2 (downstream)

EOBD code: P0430
Fault location: Catalytic converter system, bank 2 - efficiency below threshold
Probable cause: Catalytic converter, wiring, heated oxygen sensor 2 (downstream)

P1411 - secondary air injection system flow too low Bank 2.
P1423 - secondary air injection system flow too low Bank 1.
Check vacuum hoses to combi valves ,
most common split air injection pump which is riveted with aluminum rivets,ck rivets if they coming out ,pump doesn't build enough pressure.
In this case take pump out and put bolts instead of rivets all around pump case.Repl. all rivets not only broken one.Bolts sold at HomeDepot , just find a needed size.

Sounds like you have a broken boost line. So check and feel around and see if you feel air seeping out a hose. Your not getting enough air into the system

change the air fow senser.