S10/T10 P/U 2WD V6-262 4.3L VIN Z TBI (1995)
Throttle Position Sensor: Testing and Inspection
With Vehicle Control Module (VCM)
When Diagnostic Trouble Code (DTC) P0123 or P0122 is set, the VCM will use a default value for throttle position and some engine
performance will return.
A broken Throttle Position (TP) sensor can cause intermittent bursts of fuel from the injector and an unstable idle because the VCM thinks the
throttle is moving.
A scan tool reads throttle position in volts and should read about 0.45 to 0.85 with the throttle closed, ignition "ON" or at idle. Voltage should
increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT).
Scan TP signal while depressing accelerator pedal with engine stopped and ignition "ON." Display should vary from below 0.85 volt (1250 mV)
when throttle was closed, to over 4.5 volts (4500 mV) when throttle is held at wide open throttle position.
TP Sensor Output
This check should be performed when TP sensor attaching parts have been replaced. A Tech 1 can be used to read the TP signal output voltage or
1. Connect digital voltmeter J 39200 from TP sensor connector terminal "B" (BLK wire) to terminal "C" (DK BLU wire) Jumpers for terminal
access can be made using terminals "1214836" and "12014837".
2. With ignition "ON," engine stopped, the TP signal voltage should be less than 1.25 volts if more than 1.25 volts verify free throttle movement.
If still more than 1.25 volts, replace TP sensor.
3. Remove the voltmeter and jumpers, reconnect the TP sensor connector to the sensor.
