Your throttle has a backup sensor, and the data shows it
P0123, P0222 and P0122 cover paired throttle and pedal position sensors, and they show up together about half the time — evidence of a design built for redundancy, not a coincidence.
Modern throttle bodies and accelerator pedals do not carry one position sensor each. They carry two, reading in opposite directions, specifically so the engine computer can catch one of them lying. P0123, P0222 and P0122 are what that design looks like when it shows up as a fault, and our data shows the redundancy clearly.
What the codes actually mean
A throttle position sensor or accelerator pedal position sensor is usually built as a pair — two independent signals from the same physical position, one rising as the other falls, so the ECU can cross-check them against each other every fraction of a second. P0123 is throttle position sensor A reading high. P0222 is throttle position sensor B reading low. P0122 is throttle position sensor A reading low. Each one on its own describes an out-of-range voltage on one channel of that pair.
What the telemetry says
Nearly half of P0123 scans also carry P0222 — the two halves of the same sensor pair failing together at a rate that says shared cause, not coincidence. Run it from P0222's side and the pattern holds even more strongly: P0222 carries P0123 at 53.18% and P0122 at 45.93%. Two sensors reading independent circuits do not both go out of range unless something upstream of both of them — a shared 5-volt reference supply, a shared ground, or a connector carrying both signal wires — is the actual point of failure. P0113 and P0108, unrelated sensor circuits covered in a separate post on this blog, turn up here too at a lower rate, which is consistent with a wider connector or grounding issue on the same harness section rather than anything specific to the throttle.
Why this one is worth treating carefully
Unlike most of the codes on this blog, this cluster is genuinely severity-high. The throttle position sensor pair is what tells the engine computer where the throttle plate actually is — and on a drive-by-wire system, where there is no mechanical cable connecting the pedal to the throttle at all, the ECU depends on this signal to know what the driver is asking for.
Limp mode is not a malfunction — it is a safety response
When the two throttle sensor signals disagree by more than the ECU's threshold, most systems respond by cutting power delivery to a fixed, low idle-like speed — commonly called limp mode — rather than trusting a throttle position it cannot verify. That is deliberate: the alternative is letting the car act on a signal it cannot cross-check, on a system with no mechanical fallback.
If you feel the car suddenly lose power and refuse to accelerate normally, do not fight it or assume something has broken further. Get off the road when it is safe to do so and have it scanned — you are looking at exactly this fault, and the car has already done the safe thing on its own.
The pedal position sensor pair, covered by the same underlying design, carries the same consequence from the other end: if the ECU cannot trust what the pedal is telling it, it cannot safely command full throttle either.
What to do next
Check the connector at the throttle body first — a loose or corroded pin here can put both signal channels out of range at once, which matches the co-occurrence pattern better than two independent sensor failures would. If the connector looks clean, check the 5-volt reference and ground wires feeding the sensor pair for continuity and for a short to each other; a sensor pair sharing a reference voltage will show correlated faults exactly like these if that shared wire is the problem. Only test the sensors themselves — usually a simple resistance-versus-position check — once the wiring and connector have been ruled out.
Can you keep driving?
If the car is currently in limp mode, treat it as a "get it looked at now" situation rather than something to defer — you have reduced power and a throttle response the car itself does not fully trust. If the code is present but the car is driving normally, it is worth booking the check soon rather than immediately; an intermittent connection like this tends to get less intermittent over time, and you want to find it in a driveway rather than on a highway on-ramp.
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Related codes
Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.