DeVille V8-4.9L VIN B (1995)
Throttle Position Sensor: Adjustments
Throttle Position (TP) Sensor Adjustment
Due to tolerances in the throttle body, TP sensor adjustment is sometimes required.
The TP sensor adjustment procedure should be performed when:
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The TP sensor is replaced.
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The throttle body is replaced.
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The minimum idle speed adjustment has been performed.
To perform TP sensor adjustment:
1. Remove air cleaner upper housing.
2. Disable the generator by grounding the green harness connector plug adjacent to the generator.
3. Start engine, enter diagnostics and select PCM override PS03 "ISC Actuator."
4. Press the "COOLER" button on the CCP to retract the ISC Actuator. This action will disengage the NC compressor and command EGR "OFF."
The Climate Control Center display will change from "50 to 00." The ISC Actuator will slowly retract (about 20 seconds) to a fully retracted
position. Verify that the throttle lever is resting on the minimum idle speed screw. With ISC Actuator plunger fully retracted, disconnect ISC
harness.
5. Select PCM data PD0l, "TP Sensor," while still in PCM override PS03. Note the throttle position (in degrees) displayed on PCM parameter PD01.
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0.5° TO +0.5°
No TP sensor adjustment required. Reconnect ISC Actuator harness and disconnect grounding wire at generator.
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TP Sensor -10.0° to +0.6° or TP Sensor +0.6° to +90.0°. TP sensor adjustment required.
6. With the engine "OFF" and the ignition "ON," reenter diagnostics and select PCM override PS03 "ISC Actuator." Press the "COOLER" button to
retract the ISC Actuator to the minimum air setting.
7. Using a T-25 "L-Shape" Torx wrench, loosen the TP sensor screws just enough to permit the sensor to be rotated. Open the throttle slightly and
allow the throttle lever to snap shut against the minimum air screw. Adjust the TP sensor so the parameter display is 0°. Tighten the TP sensor
mounting screws with the sensor in the adjusted position. Recheck the parameter to he sure the TP sensor parameter is -0.5° to +0.5°.
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Do not use excessive force (don't pound or pry) to adjust the TP sensor or damage to the TP sensor or throttle shaft binding may occur. The TP
sensor mounting screws must be loosened to perform the adjustment.
8. Install air cleaner upper housing.
