Chapter 6 Emissions control systems
Intake arr
temperature sensor
16.3b Heating the intake air temperature sensor on a 1991 model 16.5 To check the engine coolant temperature sensor, immerse
its sensing tip in a container of water and, as the water heats up,
measure the resistance across the terminals
16.8 To check the throttle position sensor, measure the
16.14 Hook up a voltmeter between terminal 19 (throttle position
resistance between terminals 1 and 4 sensor output voltage) and terminal 24 (ground) of the engine
control unit
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16.15 If the throttle position sensor on a 2.4L model is out of
specification, adjust it by loosening the mounting screws and
rotating the sensor - clockwise rotation increases the output
voltage; counterclockwise decreases it
16.19 On 3.OL models, hook up an ohmmeter between terminals
1 and 2 with a pair of jumper wires
0.4 k-ohms. In other words, as the temperature goes up, the resistance
should go down.
4 If your readings deviate significantly from these figures, replace the
sensor. Don’t forget to plug in the electrical connector.
Engine coolant temperature sensor
Refer to illustration 16.5
5 Unplug the electrical connector from the engine coolant temperature
sensor, remove the sensor from the intake manifold and immerse its tem-
perature sensing tip in a container of water. Place a thermometer in the
water so you can monitor the temperature and hook upan ohmmeter to the
terminals of the sensor. As the water heats up, measure the resistance
across the sensor terminals (see illustration). Compare your measure-
ments with the resistance values listed in this Chapter’s Specifications.
6 If your readings deviate significantly from these figures, replace the
sensor. Be sure to apply thread sealant or Teflon tape to the threads of the
new unit to prevent leaks. Tighten the coolant temperature sensor tothe
torque listed in this Chapter’s Specifications. Plug in the electrical connec-
tor.
Throttle position sensor
Refer to ihstrafions 16.8, 16.14, 16.15, 76.19, 16.20 and 16.21
7 Unplug the electrical connector from the throttle position sensor. -
8 Measure the resistance between terminals 1 and 4 (see illustration)
and compare your measurement with the resistance value listed in this
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