NOTE: All testing procedures are made with engine at normal operating temperature.

Disconnect TPS electrical connector. Close throttle to idle position by applying approximately 18 in. Hg of vacuum to throttle opener. See Figure . Ensure throttle valve is closed.
Insert a .016" (.41 mm) feeler gauge between throttle stop screw and throttle lever. See Figure . Connect ohmmeter between terminals "C" and "D" of TPS. See Fig 1 .
Rotate TPS fully clockwise, then slowly counterclockwise until continuity exists. Hold TPS and tighten TPS screws to 31 INCH lbs. (3.5 N.m).
The TPS resistance can be checked with throttle lever in different positions to ensure correct operation. See THROTTLE POSITION SENSOR (TPS) RESISTANCE table. Once properly adjusted, install electrical connector.

Fig 1: Identifying Throttle Position Sensor Terminals

Courtesy of GENERAL MOTORS CORP.

THROTTLE POSITION SENSOR (TPS) RESISTANCE

Application & Condition

Specification

Between Terminals C & D ⁽¹⁾

0-500 Ohms

Between Terminals C & D ⁽²⁾

No Continuity

Between Terminals A & D

3500-6500 Ohms

Between Terminals B & D

At Idle ⁽³⁾

300-2000 Ohms

At Wide Open Throttle

2000-6500 Ohms

⁽¹⁾	With .012" (.30 mm) feeler gauge installed between stop screw and lever.

⁽²⁾	With .022" (.56 mm) feeler gauge installed between stop screw and lever.

⁽³⁾	To position throttle valve at idle, apply approximately 18 in. Hg vacuum to throttle opener valve.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Throttle Position Sensor (TPS)