PicoScope 7 Automotive
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Keyless entry carrier signal detector
*At Pico we are always looking to improve our products. The tool used in this guided test may have been superseded and the product above is our latest version used to diagnose the fault documented in this case study.
The purpose of this test is to evaluate the keyless entry and keyless starting system operation using a Keyless entry carrier signal detector.
These known good waveforms have the following characteristics:
Go to the drop-down menu bar at the lower left corner of the Waveform Library window and select Keyless entry antennae.
Keyless entry systems are given many alternative names but they are commonly referred to as smart entry, smart start or Passive Keyless Entry (PKE) systems.
When the vehicle is locked the system uses antennae to periodically output a low frequency (LF) radio wave signal pulse. The pulses will trigger a response in a functioning key if it is within range. If the keyless entry system detects a response from a key it will deactivate the LF radio wave signal pulsations. Multiple antennae will be placed around the vehicle to ensure that the system has good coverage. The detection area formed by the front door antenna and outside luggage antenna is approximately 0.7 to 1.0 m (2.30 to 3.28 ft.) from the outside handle of the front door and rear bumper.
Many systems will extend the intervals between the LF radio wave signal pulses if a key has not been detected within a specified time. For example, the pulse intervals may extend from 250 ms to 750 ms if no key has been detected within a period of 5 days. If there is no activity within 14 days, then the system may be deactivated altogether so as to avoid draining the vehicle battery.
Vehicle entry issues may be remedied by one or more of the following checks and actions:
The Keyless entry carrier signal detector provides a non-intrusive indication of the electrical key antenna and electrical key oscillator activity. However, there may be additional diagnosis methods at your disposal: most manufacturers will utilize self-diagnosis procedures or allow for controller interrogation with a scan tool which can support any errors found with keyless entry and keyless start.
For vehicles without self-diagnosis facilities, or where the relevant scan tool/software cannot gain controller access, the Keyless entry carrier signal detector provides essential information on whether the system is operating as it should or if there are dead zones where a key oscillator is no longer working and the key cannot be detected.
The Keyless entry carrier signal detector can be used to detect keyless start systems: most vehicles equipped with a keyless entry system will also have a keyless start system. Electrical key oscillators are positioned at various points throughout the vehicle to help detect when the key is in the car.
Electrical key oscillators can be pinpointed with the Keyless entry carrier signal detector lead by “sniffing” out the emitted radio waves. As with the electrical key antennas, the closer you are to the source, the greater the output. This process can also be used to check the start/stop button function.
Note that the keyless start/stop system may time out around 30 seconds after a door has been opened. It can only be started again when the door has been closed or opened, or by operating the courtesy light switch.
This help topic is subject to changes without notification. The information within is carefully checked and considered to be correct. This information is an example of our investigations and findings and is not a definitive procedure. Pico Technology accepts no responsibility for inaccuracies. Each vehicle may be different and require unique test settings.
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