DTC P0121: Throttle Position Sensor Circuit Range/Performance Problem: Condition

DTC is set when difference between actual throttle opening value (detected by Throttle Position (TP) sensor) and throttle opening value calculated by Powertrain Control Module (PCM) is more then predetermined, with engine at normal operating temperature and correct speed, and without intake manifold pressure variation (constant throttle). Throttle opening is calculated by PCM from engine speed and intake manifold pressure. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are:

• TP sensor malfunction.
• High resistance in TP sensor circuit.
• PCM malfunction.