PicoScope 7 Automotive
Available for Windows, Mac, and Linux, the next evolution of our diagnostic scope software is now available.
Multimeter Probes
Back-pinning Probe Set
Flexible Back-pinning Probe
Large Dolphin/Gator Clips
*At Pico we are always looking to improve our products. The tools used in this guided test may have been superseded and the products above are our latest versions used to diagnose the fault documented in this case study.
The purpose of this test is to investigate the operation of the idle and full throttle position switches.
View connection guidance notes.
These known good waveforms have the following characteristics:
Channel A indicates the operation of the (normally closed) idle position switch.
Channel B indicates the operation of the (normally open) full-throttle position switch.
There is no drop-out, noise, or hashing in either output signal.
The throttle position switch signals the movement and position of the throttle valve to the Engine Control Module (ECM). The switch unit is installed at the throttle housing and attached to the throttle butterfly spindle.
Throttle position switches can be configured in different ways, so it will be necessary to check manufacturer specifications for terminal and switching data. However, the general principles of operation are similar.
Inside the unit there are two sets of contacts, with each having an open or a closed state. This allows it to signal three possible throttle position states, such as:
The throttle position switch is usually a three-wire device with a 5 volts supply (12 volts on some very early systems). A typical pin configuration might be (Hella manufactured switch):
Throttle position switch faults can be both electrical and mechanical:
A faulty throttle valve switch can cause:
Selection of component related Diagnostic Trouble Codes (DTCs):
P0068
P0120
P0121
P0122
P0123
P0124
P0220
P0221
P0222
P0223
P0224
P0225
P0226
P0227
P0228
P0229
P0510
View more
GT028
Disclaimer
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.
We know that our PicoScope users are clever and creative and we’d love to receive your ideas for improvement on this test. Click the Add comment button to leave your feedback.