Diagnostic Trouble Code (Dtc) P0123 Throttle Position (Tp) Sensor Circuit High Input - Isuzu 1999 RODEO Workshop Manual

6E1–138 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
DIAGNOSTIC TROUBLE CODE (DTC) P0123 THROTTLE POSITION (TP) SEN-
Circuit Description
The throttle position (TP) sensor circuit provides a voltage
signal that changes relative to throttle blade angle. The
signal voltage will vary from below 1 volt at closed throttle
to about 4 volts at wide open throttle (WOT).
The TP signal is used by the powertrain control module
(PCM) for fuel control and most of the PCM–controlled
outputs. If the PCM detect a continuous open in the TP
sensor or circuit, then a code P0123 will set. DTC P0123
is a type A code.
Conditions for Setting the DTC
f The ignition is ON.
f Throttle Position sensor signal voltage is greater than
4.78 volts for a total of 0.78 second over a 1.5–second
period.
Action Taken When the DTC Sets
f The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
f The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
f The PCM will use a default throttle position based on
MAP and RPM.
SOR CIRCUIT HIGH INPUT
Conditions for Clearing the MIL/DTC
f The PCM will turn the MIL OFF on the third consecutive
trip cycle during which the diagnostic has been run and
the fault condition is no longer present.
f A history Diagnostic Trouble Code P0123 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.
f Diagnostic Trouble Code P0123 can be cleared by
using the Scan Tool's "Clear Info" function.
Diagnostic Aids
Check for the following conditions:
f Poor connection at PCM – Inspect harness connectors
for backed–out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal–to–wire connection.
f The TP sensor shares a 5 Volt reference with the MAP
sensor and Fuel Pressure sensor.
f The TP sensor share a ground with the MAP and the
Fuel Pressure sensor.
f Damaged harness – Inspect the wiring harness for
damage, shorts to ground, shorts to battery positive
and open circuits. If the harness appears to be OK,
observe the Throttle Position sensor display on the
Tech 2 while moving connectors and wiring harnesses
related to the TP sensor. A change in the display will
indicate the location of the fault.
If these codes are also set, it could indicate a
problem with the 5 Volt reference circuit or
components itself.
D06RX045