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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
P0491 - Secondary Air Injection System Insufficient Flow Bank 1
Possible causes Intake leak Damaged AIR system components Faulty AIR Solenoid Valve Faulty AIR system relay
Possible symptoms Engine Light ON (or Service Engine Soon Warning Light) P0491
Description An air pump is used on the vehicle to lower tail pipe emissions on start-up. The Powertrain Control Module (PCM) grounds the Air pump relay control circuit which energizes the Air pump. The PCM also grounds the Air combination valve vacuum control solenoid circuit, which energizes the Air vacuum control solenoid. Vacuum is then applied to both Air combination valve diaphragms which opens the shut off valves. The PCM enables both circuits simultaneously when Air system operations is desired. When the AIR system is active, then Air pump forces fresh air into the exhaust stream in order to accelerate catalyst operation. The AIR combination valves replace the conventional check valves. When the AIR system is inactive the shut off valves prevent air flow in either direction.
P0491 - Secondary Air Injection System Insufficient Flow Bank 1 Possible causes - Intake leak - Damaged AIR system components - Faulty AIR Solenoid Valve - Faulty AIR system relay
p1423 refers to secondary air injection system --insufficient flow detected causes hose connections---air valve--air pump p1421 refers to secondary air injection system bank 2 insufficient flow detected. causes-- hose connections---air valve---air pump.
A code P0411 means that there is insufficient flow in your secondary air injection system, this is totally separate from the egr (exhaust gas recirculation) system. Has the vehicle been re-scanned? You should also know that if an egr valve is stuck open, the vehicle would be almost un-driveable, as it would create a huge vacuum leak. If the same code is coming up, I would take a very close look at the hoses going to and from the injection pump. Check for any kinks or damage.
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.
P0174 - Fuel Injection System Too Lean Bank 2
Possible causes
- Intake air leaks - Front Heated oxygen sensor may be faulty - Injectors may be faulty - Exhaust gas leaks - Incorrect fuel pressure - Lack of fuel - Mass air flow sensor may be faulty - Incorrect PCV hose connection
Possible solution
Dirty air filter of faulty air flow sensor are common causes of the problem.
P0171 - Fuel Injection System Too Lean Bank 1
Possible causes
- Intake air leaks - Front Heated oxygen sensor may be faulty - Injectors may be faulty - Exhaust gas leaks - Incorrect fuel pressure - Lack of fuel - Mass air flow sensor may be faulty - Incorrect PCV hose connection
Possible solution
Dirty air filter of faulty air flow sensor are common causes of the problem.
P0401- Exhaust Gas Recirculation Flow Insufficient Dectected
Possible causes
- Harness or connectors (EGR volume control valve circuit is open or shorted.) - EGR volume control valve stuck closed - EGR volume control solenoid valve - Dead (Weak) battery - EGR passage clogged - Exhaust gas leaks
Possible solution
- Clean EGR Valve - Repair EGR harness or connector - Replaced EGR volume control solenoid valve - Replaced EGR volume control valve Code P0171- Fuel Injection System Too Lean Bank 1
Possible causes
- Intake air leaks - Front Heated oxygen sensor may be faulty - Injectors may be faulty - Exhaust gas leaks - Incorrect fuel pressure - Lack of fuel - Mass air flow sensor may be faulty - Incorrect PCV hose connection
Possible solution
Dirty air filter of faulty air flow sensor are common causes of the problem
P0174- Fuel Injection System Too Lean Bank 2
Possible causes
- Intake air leaks - Front Heated oxygen sensor may be faulty - Injectors may be faulty - Exhaust gas leaks - Incorrect fuel pressure - Lack of fuel - Mass air flow sensor may be faulty - Incorrect PCV hose connection
Possible solution
Dirty air filter of faulty air flow sensor are common causes of the problem.
Air injection check valve
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