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Mazda
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2003
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Protege5 Automatic
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Repair and Diagnosis
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Engine Controls - Self-Diagnostics
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Diagnostic Tests
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DTC P0121: Throttle Position Sensor Circuit - Range/Performance Problem
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Possible Causes
Possible Causes
MAF sensor malfunction.
PCM malfunction.
Poor connection in Throttle Position (TP) sensor signal circuit.
TP sensor malfunction.
Voltage drops in reference voltage supply or ground circuits.