Transmission Valve Body Replacement Tips
2002-2010 Jeep Liberty Alignment Service
Proper Alignment is Critical to ADAS Operation
How Do You Test Brake Fluid? (VIDEO)
Transmission Valve Body Replacement Tips
2002-2010 Jeep Liberty Alignment Service
Proper Alignment is Critical to ADAS Operation
How Do You Test Brake Fluid? (VIDEO)
Sponsored By NGK Spark Plugs
Transmission Fluid Technology: Your Guide to Understanding New Grades and Specifications
As automatic transmission technology has evolved, so have the fluids inside. With more than 20 current OE transmission fluid specifications, it can be confusing to choose the correct fluid for the transmission and customer.
In this 60-minute webinar, our presenters will discuss how to select the correct transmission fluid for today’s diverse population of automatic transmissions. The experts will also cover how to optimize your shop’s inventory to cover the broadest range of vehicles.
Speakers Mark Thorsen, Transtar Account Manager, Lubrication Technologies Mike Quigley, Director of Product Development, Lubrication Technologies Andrew Markel, Director of Content, ShopOwner
Brake & Front End serves repair shops conducting a high volume of undercar repairs by providing application-specific technical information and solutions to address emerging trends in the undercar repair segment. By subscribing, you’ll receive the ShopOwner digital edition magazine (12 times/year) featuring articles from Brake & Front End and the Brake & Front End eNewsletter (twice weekly). Access to digital editions, contests, news, and more are ready for you today!
Brake & Front End serves repair shops conducting a high volume of undercar repairs by providing application-specific technical information and solutions to address emerging trends in the undercar repair segment. By subscribing, you’ll receive the ShopOwner digital edition magazine (12 times/year) featuring articles from Brake & Front End and the Brake & Front End eNewsletter (twice weekly). Access to digital editions, contests, news, and more are ready for you today!
ByBrake and Front End Staff on Jan 31, 2022
Fuel systems can have many possible issues to diagnose. This video is sponsored by AP Emissions.
Don’t settle for “almost” - it matters where the engine is manufactured or remanufactured. Sponsored by ACDelco.
GM transmissions and transfer cases are unique to each individual vehicle. This video is sponsored by ACDelco.
Don’t settle for “almost” - it matters where the engine is manufactured or remanufactured. Sponsored by ACDelco.
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How can you diagnose what you can’t see? We’ll break it down for you!
TPMS and keyless entry can be difficult to understand because these systems rely on transmitting, receiving and decoding radio waves, but these signals are invisible. You can see wires connecting modules and components and observe them with a meter or scope but seeing radio signals takes intelligent tools.
Radio waves are a type of electromagnetic radiation that have artificially organized patterns of waves that transmit information. Still confused? Think of a TPMS sensor; it transmits a very low power signal that goes in all directions. The wave is absorbed and reflected off the vehicle and environment. The antenna on the vehicle — which could be on the windshield, in the wheel well or other locations — receives part of the wave.
TPMS sensor signals are low power and low frequency with the majority of sensors transmitting at 315 MHz or 413 MHz. Keyless entry fobs also operate at this frequency. The transmitters in TPMS sensors are low signal devices subject to FCC Part 15 and are Class C devices. The signals are unencrypted, but the signal is so minimal that it cannot be read by anyone more than 100 feet away.
The other thing to remember is that similar frequencies in the same area can interfere with each other. In the 315-413 MHz range are a lot of consumer products, like home alarm systems and home automation products like smart light bulbs. In some cases, electronic devices such as phone chargers can emit unintended electromagnetic radiation.
If a TPMS sensor transmitted all the time, that sensor will not last very long. Most TPMS sensors will transmit when movement is detected through a simple accelerometer inside. If the wheel stops moving, the sensor will stop broadcasting after a programmed amount of time. But once it is triggered, the sensor transmits on a predetermined interval set by the manufacturer. A sensor will immediately send a signal if it detects a sudden loss in pressure. A sensor never receives radio signals during normal operation. The only time a sensor receives a signal is when a TPMS tool activates the sensor by emitting an electromagnetic pulse at a specific frequency.
There are some models that can send a signal to indicate reduced battery voltage if it goes beyond a specified limit, but not all sensors send such a signal, and this information is often inconsistent. For instance, cold temperatures can cause a temporary voltage reduction that only corrects itself once the tires warm up. The only proven way to know how much battery life remains is to fully use the sensor to depletion.
The TPMS system will not turn the light on if a single transmission is not received. It takes multiple missed signals. The system knows that a missed or garbled transmission might be an external issue like a sensor on another vehicle transmitting at the same time or interference from the sensor being behind a brake caliper. It is like a misfire monitor; it only sets a code if the problem reaches a specific threshold.
How do you measure, observe and confirm a sensor or vehicle component is transmitting? The first strategy is to look for a result in the scan tool data PIDs. If you are having issues with a key fob or TPMS sensor, look at the data. It might be a command to unlock the doors that is seen in the BCM or keyless entry module.
If you are looking to measure the strength of a signal it requires specialized tools. Many TPMS tools include a feature to measure signals from key fobs and smart keys. These tools can also ping TPMS sensors and force them to transmit. This is a great feature if you are dealing with a random sensor.
The other type of radio signals you might have to deal with are carrier waves used by the keyless entry system. These radios waves range between 125 to 140 kHz. The waves are modulated to send information between the keys and antennas around the vehicle. These are for smart keys that can remain in the driver’s pocket. The antennas around the vehicle will send out these carrier waves along with the keys. These frequencies are used for very short distances to share security information. The antennas are located in the doors, tailgate and center console.
To test these antennas and keys, you will need a special probe for your scope. This probe can detect the carrier wave using a scope that has a fast sample rate. You will not be able to decode the information, but this probe can be very helpful when diagnosing a no start or condition where the owner can’t open a door.
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