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redraws factory wiring diagrams in color and includes the component, splice and ground locations right in their diagrams. Pricing: - 1 month subscription $19.95 per vehicle 1-year subscription $29.95 per vehicle 4-year subscription $44.95 per vehicle - 1-year $29.95 subscription: additional vehicles $19/95 each 5-year $49.95 subscription: additional vehicles $34.95 each Which one should YOU choose? If you’re tracking down a wiring issue, is the better choice. In most cases, their diagrams are right from the factory manuals. They include wiring diagrams and technical service bulletins. Get the BEST auto repair information and are professional-grade shop manuals-period. Continued corrosion can cause the AIR pump and switching valves to seize, at which point they must be replaced. The water can also corrode and impede the operation of the AIR switching valves. In humid conditions, the compression can cause the humidity in the air to condense against the cold metal pump structure and cause internal corrosion. What goes wrong with an AIR pump and AIR switching valves?Īny time a gas is compressed, it heats up and outside air is no exception. The problem can be a blown fuse, bad relay or an open circuit. If it doesn’t get that results, it sets a P0412 secondary AIR circuit malfunction if it finds one. By grounding the control coil, the PCM expects to see a voltage drop to almost 0. The PCM activates the AIR relay by grounding the control coil in the AIR relay. If it doesn’t see the lean condition, that would indicate a problem with the AIR relay, pump or switching valve and the PCM sets a P0411 secondary air injection system flow (low flow or no flow) malfunction.

The O2 sensor show should a lean condition due to the extra air in the exhaust stream and it must show the lean condition within a certain time frame. At the same time, it commands the switching valve to open and allow the pumped air to enter the exhaust stream. At that point it operates the AIR pump relay to switch power to the pump (electric pump draws high current, so it needs a relay to switch the power). Once the catalytic converter reaches light off temperature, the PCM begins to receive downstream oxygen content signals. The oxygen sensors have internal heaters that bring them up to operating temperature quickly. If the engine temperature is below 195°, the PCM determines the engine is “cold” and commands a rich fuel mixture. Secondary air one-way valve and solenoid How does the secondary air injection system and AIR pump work?ĭuring a cold startup the PCM monitors the engine coolant temperature sensor and upstream and downstream oxygen sensors to detect whether to turn on the AIR pump. In older vehicles the secondary air injection reaction (AIR) pump AIR was belt driven, but many late model That’s where a secondary air injection system comes into play. Once there, the catalytic converter needs extra oxygen to burn off the unburned fuel. The hot exhaust gas is what brings the catalytic converter up to light off temperature. The catalytic converter is responsible for burning off the excess fuel, but first it must reach a “light off” temperature of 400° F to 600° F. Unfortunately, the rich fuel mixture doesn’t burn completely causing some of the unburned fuel to exit with the exhaust and flow into the catalytic converter. It’s used to reduce emissions during cold starts when the engine is running on a rich fuel mixture to overcome the cold quenching effect of cold combustion cylinders.

The flipside is they have done everything correctly and you just haven't done a proper drive cycle yet.Glossary > Secondary air injection system Secondary air injection system What is a secondary air injection systemĪ secondary air injection system is part of a vehicle’s emission system. Hell, print it out and take it with you so they know you know what is going on. Say it still wont run the Secondary air monitor and I've done the drive cycle. In this case it sounds like they looked for and found an issue but did you pay for them to do that is the issue.īasically take it back. If they find another problem it may or may not fall on them since the system was indeed faulted by those things replaced and whether or not you paid for a diagnosis or just told them to replace so/so part. Incomplete diagnosis does happen and it's not either party's fault at times.įor instance, if a car is brought in on a tow-truck for a hole in the radiator, there is no way for a tech to know that your thermostat is not functioning properly until the radiator is fixed first. If they can't get it to pass, they may have misdiagnosed /incompletely diagnosed the issue and need to continue to diagnose the issue if you in-fact paid for diagnosis. You may have to leave it for a bit but if it's really fixed, they should have it back to you quickly. So take it back and have them verify the fix they did by getting it to pass the Secondary air monitor.