OBD-II trouble code
P0226: Throttle/Pedal Position Sensor/Switch 'C' Circuit Range/Performance
The third throttle or accelerator position signal is electrically valid but does not agree with the other position sensors. Nothing is shorted or open — the number is simply wrong relative to what the rest of the system is reporting.
Quick facts
- System
- Powertrain
- Category
- Throttle / Idle
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $0 – $700
- DIY difficulty
- Intermediate DIY
What does P0226 mean?
Range/performance is the most misunderstood phrase in the OBD-II vocabulary, and understanding it correctly is most of the diagnosis on this code. A circuit code — P0225, P0227, P0228 — means the module could not get a usable signal: too low, too high, or invalid. P0226 means the opposite. The module received a perfectly usable signal. It sits inside its normal voltage window. It responds to the pedal. Every static electrical test on it will pass. It is simply not consistent with what the other position sensors are reporting at that moment.
That is possible because the module never trusts a single throttle signal. On a drive-by-wire vehicle it reads several redundant position channels and continuously checks them against each other and against what the throttle actuator was commanded to do. When the 'C' channel says one thing and the rest of the system says another, the module cannot know which one is lying — it only knows they disagree — so it sets P0226 and takes the safe route.
The practical consequence is that a meter alone will not solve this code. You need to see the sensors moving together. Graphing the 'C' signal against the other position channels while sweeping the pedal slowly through full travel is the single most useful test available, because it shows exactly where the disagreement lives: a channel that reads correctly at rest and drifts apart at wide-open throttle is a different fault from one that is offset by a constant amount everywhere, which is different again from one that tracks perfectly until it hits a dead spot at one specific angle.
Those three patterns map onto real causes. A constant offset across the whole sweep usually means a shifted reference — a high-resistance ground raising the entire signal range, or a 5-volt supply that is out of specification. A progressive divergence usually means a worn sensor element whose slope no longer matches. A localized glitch usually means a worn track or a marginal internal connection at one point in the sensor's travel. And on platforms where 'C' is a throttle-body sensor, carbon buildup restricting the plate's movement produces a genuine mechanical disagreement between what was commanded and what the sensor sees — a case where the sensor is telling the truth and the throttle body is the problem.
One other cause deserves early attention because it costs nothing to rule out: a stale learned value. If the vehicle recently had a throttle body, a pedal assembly, or a battery replaced, or a module reflashed, the stored calibration may simply be out of date, and the relearn procedure may resolve the code with no parts at all.
With the redundancy check failing, the module reduces power, caps RPM, and disables cruise control, usually storing a fail-safe code from the P2104 through P2110 group alongside this one.
Common causes
- Worn 'C' position sensor whose output no longer tracks the other channels across the sweep
- High-resistance sensor ground shifting the entire signal range by a constant offset
- Out-of-specification 5-volt reference supply from the control module
- Carbon buildup in the throttle body restricting plate movement, where 'C' is a throttle-body sensor
- Binding or worn throttle plate, shaft, or return mechanism
- Sticking or worn accelerator pedal pivot preventing smooth, repeatable travel
- Stale learned values after a throttle body, pedal, battery, or module replacement with no relearn performed
- Corroded connector or a spread terminal adding resistance to the signal path
- Chafed wiring adding resistance without fully opening the circuit
- Low system voltage from a weak battery or failing alternator skewing all sensor readings
- Vacuum leak or induction restriction making commanded and actual airflow disagree
- Rarely, control module calibration or software fault
Symptoms
- Check engine light is on
- Reduced engine power warning on the dash
- Hesitation, surging, or an inconsistent feel from one pedal press to the next
- Rough or unstable idle, or an idle slow to settle after lifting off
- Poor throttle response, especially at part throttle
- Cruise control disabled or dropping out
- Reduced fuel economy
- Companion codes such as P0225, P2135, P2138, or a P2104-P2110 fail-safe code
Diagnostic steps
- 1.Confirm in service data which physical sensor your manufacturer designates 'C' before doing anything else. The letter assignment varies by platform and guessing leads to replacing the wrong part.
- 2.Scan every module and record all stored and pending codes with freeze frame data. Note the RPM, load, and throttle angle at which the code set — a range/performance code that only sets at a particular operating point is a strong clue.
- 3.Ask what changed just before the light appeared. A recent throttle body, pedal, battery, or module job makes a stale learned value the likely cause and the relearn the likely fix.
- 4.Test the battery and charging system. Low voltage and excessive ripple shift sensor reference values and produce correlation faults on healthy sensors.
- 5.Graph the 'C' signal against the other position channels while sweeping the pedal slowly through full travel and releasing it. This is the central test for this code — the shape of the disagreement identifies the fault.
- 6.Classify what you see. A constant offset across the whole sweep points at ground or reference. A progressive divergence points at a worn sensor. A momentary dropout at one repeatable angle points at a worn track inside the sensor.
- 7.Perform a loaded voltage-drop test on the sensor ground. This is the most common cause of a constant-offset pattern and an unloaded resistance check will not reveal it.
- 8.Verify the 5-volt reference at the sensor connector with the key on, measured against a known-good chassis ground.
- 9.If 'C' is a throttle-body sensor, remove the intake duct and inspect the bore and plate for carbon. Check that the plate moves freely and closes fully with no binding.
- 10.Compare commanded throttle position against actual throttle position in live data. A persistent gap between the two points at a mechanical restriction rather than an electrical fault.
- 11.Inspect the connector for corrosion, moisture, and spread terminals, then wiggle-test the harness with live data displayed.
- 12.If everything tests good, run the relearn procedure; if the code returns, replace the affected pedal assembly or throttle body and relearn again.
Repair cost
$0 – $700
The low end is genuinely zero on this code — running a relearn procedure or reseating a connector resolves a real share of range/performance faults with no parts at all, particularly when the code appeared right after other work. Diagnosis typically runs $75-$150, and expect the higher end of that because this code requires graphing live data rather than a single measurement. Throttle body cleaning is roughly $80-$200. Wiring or ground repair lands around $100-$350. An accelerator pedal assembly is $150-$400 installed, a throttle body $250-$700 installed. A relearn is required on most platforms after either part.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with throttle body cleaning preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.