Sensor And Module Repairs

Sensor Repairs Aren't That Complicated

Hendersonville Muffler and Brakes started repairing cars and trucks here in Hendersonville, Tennessee many years ago. By the time we had moved to this location cars and trucks were already using sensors of different types all over, (Mercedes Benz, Volkswagen and several other European manufaturers were using sensors and modules in 1967). There were pressure sensors, temperature sensors, oxygen sensors, reference sensors, wheel speed sensors, camshaft position sensors, crankshaft position sensors, transmission speed sensors and transmission pressure sensors and switches. There are other sensors in the car as well but the point is that most of these sensors have been in use for more than 40 years. When we hear mechanics talking about how complicated the new cars are we sort of laugh. Most of this technology is at least 40 years old! If your mechanic hasn't learned how to diagnose and repair sensor problems yet they probably never will.

Sensor Diagnosis Is More Complex But Easier

I don't pretend to tell you that cars and trucks have not become more complex. Automotive computer systems have changed and evolved over time and newer cars use more sensors than they used to. The original engine management systems on controlled engine management functions and were called ECM. later transmission modules were added and called TCM. Most modern cars use what is called a PCM which controls the engine, transmission, air conditioner, heater, and works with the other modules in the vehicle. Sensors and modules are used in different ways as many sensors now report to several control units. For instance wheel speed sensors report the speed of the wheels to the PCM and this information is used for the ABS system as well as for the Traction Control System and the transmission computer. The transmission speed sensor reports to the PCM to determine engine loads. The transmission speed sensor also reports the speed of the transmission to the transmission computer to determine shift speeds and the traction control computer module to be compared with the wheel speed sensors and determine if the wheels are losing traction.

In about 1985 cars started using on board diagnostic systems. The systems really didn't diagnose the car but they monitored sensors and reported when either the sensor or the item the sensor controlled malfunctioned. Tools to read this data from the computer became known as scanners. We have owned a lot of different scanners since they were introduced. Today we have the latest scan tools and we can communicate with the automotive computers and see live data. By watching the sensors work on the scanner we can determine whether the sensor is functioning correctly. In 1985 it became a law that all cars and trucks sold in the United States supply data to a scan tool to make them easier to diagnose. in 1996 all cars needed to have the same plug for diagnosis and the system was renamed OBDII. Troubles that were detected by the on board automotive computers were called trouble codes.

Good Tools Need Good Technicians To Run Them

A good automotive scanner in the hands of a qualified technician is a great tool to diagnose sensors, the components that they operate, and the wiring that connects the sensors to the PCM and the wiring that connetcts the PCM to the output devices. The invention of scanners made diagnosing cars easier but many or our clients who had their trouble codes read at the local auto parts store and then bought the part the auto parts store clerk recommended have discovered that a person reading an automotive scanner might not be an automotive technician. Just because the scanner says there is a problem with a sensor does not mean that sensor is bad. Scanners, lab scopes, and electrical multimeters are great tools that we use every day. These tools make it easier to diagnose the more complex computer systems and the various sensors that feed information to them. But in the end if you want to have your car or truck running correctly you should seek a qualified technician like the one's at Hendersonville Muffler and Brakes in Hendersonville, Tennessee.