DH2 - Check For Stuck Throttle Plate

Diagnostic Trouble Code (DTC) 121 indicates the Throttle Position (TP) sensor's rotational setting may be out of Self-Test range.

Possible causes:

- Binding throttle linkage.

- TP sensor may not be seated properly (tightened down).

- Damaged TP sensor.

- Damaged Powertrain Control Module (PCM).

- Visually inspect throttle body and throttle linkage for binding or sticking.

- Verify the throttle linkage is at mechanical/closed throttle. Check for: binding throttle linkage, speed control linkage, vacuum line/electrical harness interference, etc.

- Does throttle move freely and return to closed throttle position?

Yes -- Go to DH3. DH3 - Attempt to Generate DTC 122

No -- Service as necessary. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)