The throttle body position sensor is designed to send a value to the computer to allow the correct mixture of fuel required on that specific value. The TPS is as a butterfly only it is an electronic butterfly that also sends a signal back to the computer on its position. The TPS will suffer from clogging up as it has fine circuits or holes around the closing points on one side. On the inlet manifold side of the butterfly it may be seen as being very dirty. This must be serviced at least every 50,000kms to ensure a consistent idle.
THINGS TO LOOK FOR
The TPS is a component that should be serviced and an examination will determine its effectiveness. A check inside the TPS will show a butterfly and on the other side of the butterfly if any muck or, blackness has built up around the venturi, this should be cleaned out with a rag and made spotless as this could affect the idle control. The difference between a good idle and a poor idle is a clean TPS.
IS IT EXPENSIVE TO REPAIR?
The TPS rarely goes wrong except for the electronic potentiometer, attached to the TPS throttle, may malfunction or the contacts may fail or it may have a flat spot. These are best calibrated and checked by your local auto electrician. If the prices quoted for the TPS or the throttle positioner switch is a bit expensive, try the wreckers. Remember to keep the receipt as the TPS is another component that could go wrong after it has been fitted.
This article is found in the Virtual mechanic CD Rom
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By Darren Gow-Brown, Melbourne Australia ©2009