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Home >> Pontiac >> 2001 >> Firebird Formula, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 5.7L >> Diagnostic Tests >> DTC P0121: Throttle Position Sensor Circuit Insufficient Activity >> Diagnostic Aids

Diagnostic Aids

A skewed MAP sensor may cause this DTC to set. If TP sensor operates properly and DTC continues to set, check for proper operation of MAP sensor.

PCM 5-volt reference circuits are internally connected within PCM. If DTC is intermittent, performing DTC P1121 may help isolate concern. See DTC P1121: TP SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE .

If problem is intermittent, see INTERMITTENT TROUBLE CODE DETERMINATION  under SELF-DIAGNOSTIC SYSTEM.

Fig 1: Identifying Throttle Body Components
G00035791Courtesy of GENERAL MOTORS CORP.