Code po 491 and po 492

replace the items and then reset the ECM using a scan tool

fix the reported code fault sensors then reset the ECM using a scan tool
turning off lights does not fix problems

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.

code po412 refers to secondary air injection(AIR) solenoid circuit malfunction Cause may include Wiring---AIR solenoid and ECM I would replace the AIR solenoid or check for power to it first.

PLEASE RATE THIS REPLY FOR ACCURACY

Code 491 is for insufficient secondary air injection flow bank one.
There is a device that pumps fresh air into the exhaust system to lower emissions. The sensor that measures air flow is telling the computer the air flow is below standard.
The system would need to be tested.

P0410 - SECONDARY AIR INJECTION (AIR) SYSTEM
P0491 - SECONDARY AIR INJECTION (AIR) SYSTEM INSUFFICIENT FLOW (BANK 1)

Secondary air injection (trademarked as Air Injection Reactor) is a process where fresh air is injected into the exhaust system to allow for a fuller combustion of exhaust gasses.

The possible causes are:
SAIR pump low or now air flow
SAIR bypass solenoid leaking/blocked or stuck open/closed
SAIR diverter valve leaking/blocked or stuck open/closed
SAIR air hose restriction
SAIR vacuum hose restriction or leaking

Check to make sure your air filter isn't dirty - and replace if needed. Otherwise I would suggest having your local trusted auto repair facility diagnose and repair the issue. A scan tool will be needed to properly diagnose the issue.

Both are fuel injection trouble codes. Possible causes are:

• Air pump output is blocked or restricted
• AIR bypass solenoid is leaking or it is restricted
• AIR bypass solenoid is stuck open or stuck closed
• Check valve (one or more) is damaged or leaking
• Electric air injection pump hose(s) leaking

1997 BMW 328I 2.8L Customer Concern: MIL is on with trouble codes P1421 and P1423, for incorrect secondary airflow on both cylinder banks. Tests/Procedures: 1. Perform a functional test of the Air Injection Reaction (AIR) system. Tee a vacuum gauge into the vacuum hose attached to the diverter valve, located on the cylinder head towards the front of the engine.

2. Allow the vehicle to sit over night. Start the engine (cold) while monitoring the amount of vacuum on the gauge at startup. At temperatures from -10 to 40 degrees Celsius, there should be at least 17 inches of vacuum. At the same time, the AIR pump should run and pump a large volume of air into the exhaust. Potential Causes: A.I.R. Pump
Air Pump Relay
Restricted Cylinder Head
Diverter Valve
Tech Tips: These codes are related to a problem detected in the Secondary Air Injection system. Scan tools with BMW software include a feature to command the AIR pump on and off. The pattern failures for these codes are the AIR pumps due to leaks in the diverter valve and moisture or condensation in the AIR pump.

Possible fix but not all items. Just areas to look at:
Confirmed Fix - A.I.R. Pump - A.I.R. Diverter - A.I.R. Pump, Air Injection Reaction Diverter (AIRD) Valve - Air Injection Reaction Diverter (AIRD) Valve - Check Valve, Secondary Air Pump - Diverter Valve Vacuum Lines

this is what the code means
P0492
Secondary Air Injection System (Bank 2)

Code 0492 means: secondary air system-bank 2, maybe the problem is there?