Throttle Position Sensor (Tps) - Jeep Cherokee 1988 Quick Start Manual

include Park/Neutral switch (automatic transmission only), air
conditioning clutch, and Sync Pulse switch. When A/C or Park/Neutral
switches supply ECU with an "on" signal, module signals ISS motor to
change idle speed to a specific RPM.
With A/C on and throttle blade above a specific angle, ECU
de-energizes A/C relay, preventing A/C clutch from engaging until
throttle blade angle is reduced.
Sync pulse switch, located within distributor, generates a
signal to ECU, helping to properly synchronize sequential fuel
injection opening with intake valve opening.
ADJUSTMENTS
NOTE: Idle speed and air/fuel mixture are controlled by ECU and
are non-adjustable. On-car adjustment procedures for other
components should not be necessary during normal vehicle
operation or maintenance. Adjustments of components should
only be required when a faulty component is replaced with a
new one.

THROTTLE POSITION SENSOR (TPS)

1) Turn ignition on. Check throttle position sensor input
voltage. Connect voltmeter negative lead to terminal "B" (M/T), or
terminal "D" (A/T) of sensor connector. Connect voltmeter positive
lead to terminal "A" (M/T and A/T) of sensor connector.
NOTE: On (A/T) models, connector terminals are identified by
letters molded into back of connector. On all models, do not
disconnect TPS harness connector. Insert voltmeter test
leads through back of wire harness connector. On some
models, it may be necessary to remove throttle body from
intake manifold to gain access to sensor wire harness.
2) Move and close throttle plate completely (M/T and A/T).
Ensure throttle linkage contacts stop. Note voltmeter reading. Input
voltage at terminals "B" and "A" (M/T), or terminals "A" and "D"
(A/T) should be 5 volts.
3) Return throttle plate to closed throttle position (M/T
and A/T). Check sensor output voltage. To do so, disconnect voltmeter
positive lead from terminal "A" and connect it to terminal "C" (M/T),
or terminal "B" (A/T).
4) Maintain throttle plate in closed position (M/T and A/T).
Ensure throttle linkage contacts stop. Note voltmeter reading. Output
voltage should be .8 volt (M/T), or 4.2 volts (A/T).
5) If output voltage is incorrect, loosen bottom sensor
retaining screw and pivot sensor in adjustment slot for a coarse
adjustment. Loosen top sensor retaining screw for fine adjustments.
Tighten screws after adjustment.
TESTING & TROUBLE SHOOTING
PRELIMINARY CHECKS & PRECAUTIONS
Subsystem Checks
The following systems and components must be in good
condition and operating properly before assuming a fuel injection
system malfunction.
* Air filter.
* All support systems and wiring.