So we’ve decided to take the bitter pill. We have been dealt a P0411 secondary air injection malfunction. To understand what that means we’ll have to understand what the secondary air injection is and what it is meant to do when operating correctly.

Generic Scan Tool

We’re mostly familiar with the catalytic converter that has necessitated the use of unleaded gas since around 1975. 3-way catalytic converters break down hazardous carbon monoxide to harmless carbon dioxide. They also break down toxic hydrocarbons into carbon dioxide and water while reducing nitrogen oxides to regular nitrogen and oxygen.

For the Cat to do it’s job it has to be hot which can take a while. In order to meet strict emissions standards an air pump has been added to heat the Cat up sooner and reduce harmful emissions quicker. Pump air into the exhaust and it gets hot more quickly. When the Cat reaches 400 to 600 degrees Fahrenheit it begins to clean up the exhaust.

To let you know if the emissions system is working properly a number of self diagnostic regimens have been programmed into the engine management systems. One is a self test of the air injection or secondary air pump.

If that self test fails your check engine light illuminates and a P0411 diagnostic trouble code is stored in your engine management processor. In this case the processor is called DME.  Not a fun as MMI but DME serves it’s purpose.

Some where in there is a dump valve

After checking the VSV for proper operation and confirming the Air Pump actually pumps air, it’s time to dig into the engine to test the valves and clear the Air passages if possible.

Removing a few choice components on the Porsche 911 makes access to the divert-er or “Dump” valve and check valve possible. Porsche uses a vacuum reservoir to help vacuum operated function during low engine vacuum conditions. It is mounted on a fixture which bolts over the air passages we are looking for.

Ahhhh! there it is. The very dangerous and highly elusive Dump valve. I think I’ll make it mad.

 The larger threaded hole is where the check valve attaches to the fixture and the more silver colored smaller threaded hole is for the air line that feeds the right cylinder head.

The check valve will be replaced even though it still passes air. More importantly shop air will be forced through the air passages in an attempt to open them so the Air can reach the exhaust side of the cylinder heads.

Air line to the right side cylinder head

So we’ll blast out the passage ways, reassemble and test the Secondary Air injection. Manually starting the pump we got an acceptable voltage change in the O2 sensors. After two drive cycles the On Board Diagnostics, checked off the Secondary Air Injection as functioning properly. It’s now OK to turn the car back to the customer with the cravate that we can not know how clean the passageways are. They are not likely to improve but are passing enough air at this time to satisfy EPA standards as programmed into DME and monitored by OBD II

The idea behind the “Smart car” was to create a vehicle easy to park and short enough to allow “nose-in” parking. Its length of 98.4 in would equal the width of a regular parking slot, allowing two or three Smarts to park in the space as one normal car.

The project, started by Swiss watch manufacturer Swatch was nicknamed the “Swatchmobile”. The name Smart is an acronym for Swatch Mercedes ART. Intended to use innovative features (such as a hybrid engine) and be affordable for young people.

Origionaly known as the Swatch

Thanks for visiting our Blog Site. We are still under construction. What you may expect in the future is:

1. A regular blog on motor sport, SCCA, Formula 1, WRX and endurance racing. Probably won’t be anything of interest here for NASCAR  and little for CART fans.

2. A tech site highlighting Technical Service Bulletins that effect Mercedes Benz, Toyota, BMW and Volkswagen/Audi car owners.

3. Some excellent technical and performance car videos.

4. Tech tips with photos, how to helps for the folks who love their cars and love to tinker.

If you have and suggestions on possible topics or comments e-mail me Bob Taylor bob@masterautotechllc.com