Turn the ignition off
Locate the throttle position sensor
Inspect the sensor connector and wiring for damage
Set a digital multimeter to measure voltage
Back-probe the sensor signal wire and ground wire
Turn the ignition key to ON without starting the engine
Check the reference voltage at the sensor
Check the ground circuit for continuity
Measure the signal voltage at closed throttle
Slowly open the throttle by hand
Watch for a smooth, steady voltage increase
Check for dead spots, drops, or jumps in voltage
Compare readings to the manufacturer specifications
Test sensor resistance if specified by the service manual
Wiggle the wiring harness while monitoring readings
Replace the sensor if readings are out of specification
Clear any trouble codes after repair
Recheck sensor operation after installation