DTC P0121 - Throttle Position (TP) Sensor System Performance

WARNING: This page is about a different car, the 1996 Suzuki Sidekick. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If DTCs P0121, P0122 and P0123 are set together, diagnose P0122 and P0123 first.

Start engine and allow to reach normal operating temperature. Turn engine off, leaving ignition on. Using a voltmeter, measure voltage between ground and PCM harness connector "B", terminal No. 17. With throttle fully closed, reading should be .35-.65 volt. With throttle fully open, reading should be 3.5-4.5 volts. Ensure voltage varies with throttle position. If reading is not as specified, adjust TP sensor. See ADJUSTMENTS - 1.8L article. If adjustment cannot be obtained, replace TP sensor. Retest system.