Testing the TPS

From: Bob Tom (tigers@bserv.com)
Date: Thu Oct 28 1999 - 07:48:20 EDT


To test the Throttle Position Sensor, you will need a scan tool
to check the sensor voltage. Make sure the truck is in Park.
As engine speed surges the TPS volts will increase by .2 to .3
volts without a change in throttle position. If this is the case,
replace the TPS switch.

ASIDE. The rpm surge is a common 'no fault' driveability problem
associated with a fault TPS. At idle, engine speed will increase
about 400 rpm for no apparent reason at normal operating temp.
Surging may also occur under normal driving conditions where
speed will increase and then slow down without changing throttle
position.

Other malfunctioning sensors (MAP and O2) may also give similar
symptoms. I haven't come across a way of testing these other
sensors but, if I do, I'll post. BTW, I did come across something
that said that "average" life for O2 sensors is about 60,000 mi.



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