Fault code P044F is called “Secondary Air Injection System Switching Valve “A” Circuit High” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P044F
Error code P044F refers to the emission system. The AIR pump directs air into the exhaust to reduce emissions. It takes in outside air and pumps it through two one-way check valves into each exhaust outlet group.
The error indicates a high signal level in the “A” switching circuit of the secondary air injection system, which is installed on some vehicles. The purpose of the system is to force atmospheric air into the exhaust system during cold starts.
This helps to burn unburned or partially burned hydrocarbon molecules in the exhaust gas stream. Which results from incomplete combustion during cold starts when the engine is running on a highly enriched fuel-air mixture.
Secondary air systems usually consist of a high-power air pump in the form of a turbine, a relay to control the pump motor on and off. As well as a solenoid and a check valve to control the air flow. In addition, there are various tubes and ducts corresponding to the application.
During sudden acceleration, the air pump is switched off to prevent back exhaust. For self-testing, the AIR system will be activated by the PCM and fresh air will be routed to the exhaust system.
The oxygen sensors perceive this fresh air as a poor mixture condition. A short term fuel adjustment should then occur to compensate for the lean state.
The PCM expects this to occur within a few seconds during the self-test. If it does not see a short-term increase in fuel correction, the PCM interprets this as a fault in the AIR system, and writes code P044F to memory.
Symptoms of vehicle malfunctions
The main signal that an error P044F has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be stored as a fault).
- On some European vehicles, the contamination control light will illuminate.
- Noise from air pump due to mechanical wear or presence of foreign objects in it.
- The engine does not accelerate well.
- The engine may run on too enriched mixture, if an excessive amount of air enters the exhaust manifold.
- Sometimes there may be no symptoms, despite a stored fault code.
The severity of this code is not high, but the car is unlikely to pass an emissions test. Since when the error P044F appears, the toxic emissions will increase.
Factors that can cause this error code
The error code P044F can mean that one or more of the following problems have occurred:
- Pump check valves have failed.
- Secondary air pump relay is faulty.
- Problem with control solenoid.
- Rupture or leak in hoses or ducts.
- Fouling in hoses, ducts, or other components.
- Moisture in pump and motor.
- Broken or interrupted power supply to pump motor due to bad connections or damaged wiring.
- Blown secondary air pump fuse.
- Sometimes faulty PCM is the cause.
How to fix or reset OBD-2 code P044F
Some suggested steps for troubleshooting and fix the error code P044F:
- Connect the OBD-II scanner to the vehicle’s diagnostic connector and read all stored data and error codes.
- Before proceeding with diagnosis code P044F, clear any other errors that may be present.
- Visually inspect the electrical wires and connectors related to the secondary air pump.
- If necessary, repair or replace any shorted, broken, damaged, or corroded components.
- Check the secondary air pump relay.
- Test the secondary air pump resistance.
Diagnose and repair of problems
Code P044F is set when there is no outside air to burn off the excess hydrocarbons in the exhaust system during cold start. This causes the voltage on the front oxygen sensor not to drop to the set level.
The diagnostic procedure requires the engine to be cold, ideally with the vehicle idling for at least 10-12 hours. After that, you must connect the diagnostic tool and start the engine.
The voltage on the front oxygen sensor should drop below 0.125 volts after about 5-10 seconds. The fault in the secondary air system will be confirmed if the voltage does not drop to this value.
If the voltage does not drop to 0.125 volts, but you can hear the air pump running, check all hoses, air lines, valves and solenoids for leaks. Also remember to check all hoses, ducts and valves for obstructions such as carbon buildup or other blockages.
If the air pump won’t turn on, check all relevant fuses, relays, wiring, and pump motor for continuity. If necessary, replace or repair failed components.
When all checks have been completed but the P044F malfunction persists, it may be necessary to remove the exhaust manifold or cylinder head. To gain access to the system ports in order to clean the fouling.
On which vehicles does this problem occur most frequently
Fault code P044F can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Jeep
- Mercedes-Benz
- Nissan
- Toyota
Fault code P044F can sometimes be found with other errors. The most common are the following: P0410, P0411, P0412, P0413, P0414, P0415, P0416, P0417, P0418, P0419, P041F, P0491, P0492.
