P0228
Throttle/Petal Position Sensor/Switch C Circuit Low Input
Powertrain Speed/Idle Control Throttle Control Sensor 🟡 Moderate — Fix within a week
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What This Actually Means
In plain language — no jargon

The throttle pedal position sensor is sending a voltage signal that's too low to the engine computer, like a dimmer switch stuck at the bottom position. The ECU can't properly read how far you're pressing the gas pedal.

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Symptoms You May Notice
3 known symptoms for this code
Check Engine Light illuminated
Engine hesitation or poor acceleration response
Limp mode or reduced engine power
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors the analog voltage output from the throttle position sensor (TPS) or electronic pedal sensor as it ranges from idle to full throttle. The sensor voltage should increase proportionally as the pedal is pressed; when voltage stays abnormally low, the ECU logs a fault. This low-voltage condition prevents proper fuel delivery and ignition timing adjustments.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
TPS Voltage 0.5V to 4.5V (idle to WOT) Below 0.2V or stuck low
Voltage Transition Smooth, linear increase with pedal movement No change or erratic low readings
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Electrical connectors and wiring harness
Inspect and clean the throttle sensor connector and wiring for corrosion, loose pins, or damaged insulation.
2
Throttle Position Sensor (TPS) or Pedal Position Sensor
Replace the sensor if voltage remains low after connector inspection and cleaning.
3
ECU or PCM reprogramming/replacement
If voltage reads normal but fault persists, the ECU may need reprogramming or replacement.