VW OBD II Revisited: Good Vehicle Service History Helps Determine Causes of Repeat Failures
After 10-plus years of dealing with OBD II, it should be apparent that we are on a learning curve that probably has no end. Almost daily we have a VAG model come into the shop with a check engine light on, or a “state OBD II failure” form. Although we have the latest scanner software
Exhaust & Emissions: Converters & O2 Sensors
What’s the most important emissions control device on a vehicle today? The catalytic converter, because it cleans up any exhaust pollutants that exit the engine. It’s a hot job (literally) with operating temperatures running between 600 to 1,000
Tech Tip: Water Pumps – Why They Fail and When to Replace Them
If you’ve wondered how much work a water pump must do, remember that only about 30 percent of the heat energy produced by combustion results in mechanical energy. That estimate, of course, is a mathematical comparison between the heat value of the gasoline going into the engine, and the heat value of the mechanical energy coming out of the engine. The remainder of combustion heat must then be dissipated into the atmosphere through the exhaust, lubrication and cooling systems.
Exhaust Parts
Too Much Weight
Diagnostic Solutions: Air Flow Sensors…Understanding Their Function & Potential Problems
Most of us remember the “good old days” when an engine’s air/fuel (a/f) ratio was controlled by a mechanically operated carburetor. Due to the inherent design limitations of mechanical systems, however, carburetors don’t respond efficiently to changes in barometric pressure, temperature and humidity. In the quest for improved fuel economy and reduced exhaust emissions, import
Replacing Oxygen Sensor: Saving the Environment and Your Customer’s Catalytic Converter
The oxygen (O2) sensor is the master switch in the fuel control feedback loop. The sensor monitors the amount of unburned oxygen in the exhaust and produces a voltage signal that varies from about 0.1 volts (lean) to 0.9 volts (rich). The computer uses the O2 sensor’s signal to constantly fine tune and flip-flop the
Marketing Mufflers: Muffler Replacements Are a Fast, Easy Way to Improve Your Shop’s Bottom Line
Have muffler inspections become a low-priority undercar service in your shop? With the introduction of stainless-steel exhaust systems into the import market, it’s easy to forget that muffler and related exhaust parts sales are still a lucrative service that can enhance any profit and loss statement. Muffler replacements can be profitable at any skill or
OBD II Diagnostics: Checking into Mode $06
In this scan tool diagnostics article, we take a look at Mode $06 functions which govern non-continuous monitors (EVAP, catalyst, EGR, etc.)
Monitoring Emission Efficiency With O2 Sensors
As modern OBD II technology marches on, it’s clear that the zirconia-based oxygen sensor now is being sold more as a basic repair part than as a preventive maintenance part, and it changes the way we diagnose and sell oxygen sensors. To illustrate the difference, let’s remember that an oxygen sensor replacement used to be
Muffler Technology: A Look Inside
Is a muffler nothing more than a steel can with some baffles and tubes inside? That’s how most mufflers look, but there’s a lot more to muffler science than meets the eye. A muffler’s job is to muffle sound. That’s why we call them mufflers. In England they’re called silencers. Regardless of the name, they
Checking into Mode $06
Mode 06 is the actual system test data that OBD II looks at when it decides to set a pending code or a current fault code. If the test data is within the limits established by the vehicle manufacturer, the item gets a PASS and no codes are set. But if a value is out of range, OBD II flags it with a FAIL and keeps an eye on the component until the system monitor has run at least twice. Then, if the problem is still there, a DTC is set and the MIL light comes on.