Oxygen (O2) Sensor
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Monitors exhaust oxygen to optimize air-fuel ratio.
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Failure leads to rich/lean mixtures, poor mileage, and emissions issues.
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Common codes: P0130–P0161 (circuit faults, slow response, heater issues).
MAP Sensor (Manifold Absolute Pressure)
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Measures intake pressure to gauge engine load.
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Faults cause incorrect fuel injection and ignition timing.
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Common codes: P0105–P0109 (range/performance/circuit problems).
MAF Sensor (Mass Air Flow)
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Quantifies air entering the engine.
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Dirty or failed units result in hesitation and stalling.
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Common codes: P0100–P0104 (signal low/high input faults).
Throttle Position Sensor (TPS)
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Reports throttle opening to the ECU.
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Issues lead to poor acceleration and transmission shifts.
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Common codes: P0120–P0124 (correlation/voltage errors).
Coolant Temperature (ECT) Sensor
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Tracks engine temp for cold starts and fan operation.
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Bad readings cause hard starting and excess fuel use.
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Common codes: P0115–P0119 (signal faults).
Camshaft Position (CMP) Sensor
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Syncs fuel injection and ignition timing.
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Failure triggers misfires or no-start conditions.
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Common codes: P0340–P0349 (circuit faults).
Knock Sensor
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Detects detonation (knocking) to protect the engine.
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ECU retards timing, reducing power.
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Common codes: P0325–P0334 (circuit/performance issues).
Fuel Pressure Sensor
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Monitors rail pressure for efficient combustion.
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Faults disrupt fuel delivery.
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Common codes: P0087–P0093 (pressure extremes/leaks).
Pro Tip: Sensors may test fine—check wiring, vacuum leaks, or ECU voltage first. Always scan live data, not just codes.
Source: Dr. Mechanics Facebook