What does the “delta pressure method” mean?
a. Change the inflation pressure
b. Activate the sensor so it broadcasts the pressure to the scan tool
c. Inflating the tire to the specified pressure
d. Using a handheld tester to read the pressure as reported by the sensor
The correct answer and explanation is:
Correct Answer: b. Activate the sensor so it broadcasts the pressure to the scan tool
Explanation:
The “delta pressure method” refers to a technique used in tire pressure monitoring systems (TPMS) diagnostics and sensor activation. In this method, a sensor in the tire is stimulated or triggered to broadcast its pressure data to a scan tool, enabling the technician to read and analyze the information. This process ensures that the TPMS sensor is functioning correctly and transmitting accurate data.
Key Aspects of the Delta Pressure Method:
- Activation of the Sensor:
- The TPMS sensor must be activated to send a signal. This can be done by applying specific methods, such as using a TPMS scan tool or inflating or deflating the tire to create a significant change in pressure. The term “delta” signifies a change, emphasizing the role of pressure variation in triggering the sensor.
- Pressure Change to Stimulate Broadcast:
- Sensors typically remain in a dormant state to conserve battery life. A noticeable change in tire pressure (e.g., increasing or decreasing by a few psi) causes the sensor to wake up and transmit its data. This change is used diagnostically to ensure the sensor’s ability to detect pressure fluctuations and relay accurate information.
- Reading Data with a Scan Tool:
- Once activated, the sensor transmits pressure data to a compatible scan tool, which displays real-time tire pressure readings. This process helps identify issues such as incorrect pressure, sensor malfunctions, or calibration problems.
- Common Use Cases:
- The delta pressure method is particularly useful for diagnosing TPMS-related problems, validating sensor accuracy, and confirming system functionality after repairs or tire replacements.
In summary, the delta pressure method involves triggering the TPMS sensor to broadcast its data by inducing a pressure change, allowing technicians to verify sensor performance using a scan tool.