P0223
Throttle/Pedal Position Sensor/Switch B Circuit High InputP0223 is a generic OBD-II powertrain diagnostic trouble code: Throttle/Pedal Position Sensor/Switch B Circuit High Input. It is logged by the engine control unit when the throttle monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0223 means
P0223 is triggered when the PCM detects that the throttle position sensor (TPS) or accelerator pedal position (APP) sensor "B" circuit is producing a voltage signal that is persistently above the manufacturer's maximum calibrated threshold — typically above approximately 4.5 V when the throttle should be at or near the closed position, or sustaining a near-reference-voltage (≈5 V) reading independent of actual throttle movement. In normal operation the B-channel rises from ~0.5 V (closed) to ~4.5 V (wide open); a stuck-high reading suggests the signal wire is shorted to the 5 V reference or power supply, the sensor's internal track has failed high, or there is an ECM input fault.
A stuck-high B-channel is considered a potentially dangerous fault because it could be misread by the PCM as a wide-open-throttle command, which is why the PCM immediately forces a failsafe strategy rather than attempting to control the throttle using the A-channel alone. In most implementations this results in limp mode or a forced idle, and the vehicle will not accelerate normally until the fault is cleared and the channel returns to a plausible range.
P0223 often appears alongside P0220 (generic B-circuit malfunction) or P2135 (TPS A/B correlation fault), and may also be seen with P0122/P0222 if a short to reference simultaneously drags the A-channel low. Systematic voltage testing — rather than immediate sensor replacement — is the most efficient diagnostic path, since a shorted wire is at least as likely as a failed sensor.
Common causes
Most-frequently reported root causes when P0223 is logged.
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1
B-channel signal wire shorted to the 5 V reference supply line within the sensor connector or wiring harness, clamping the signal near reference voltage.
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2
B-channel signal wire shorted to a battery voltage (12 V) line in the harness, driving the signal above the ECM's 5 V window.
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3
Faulty TPS with a failed B-channel internal resistive track that outputs a fixed high voltage regardless of throttle plate position.
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4
Faulty APP sensor with B-channel internal failure holding output near maximum voltage independent of pedal position.
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5
Water ingress or corrosion in the connector bridging the B-channel signal pin to the reference voltage pin.
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6
Damaged connector with bent or touching pins internally shorting signal to reference inside the plug body.
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7
Defective PCM input circuit reading the B-channel voltage higher than actual (rare, diagnose after external wiring and sensor are confirmed good).
Symptoms drivers notice
How to diagnose P0223
A typical diagnostic flow when this code is present.
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1
Connect an OBD-II scan tool and read all stored codes; specifically note whether P0120, P0220, P0222, or P2135 are also present, as these help distinguish a wiring short from a sensor-only fault.
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2
Monitor live B-channel voltage on the scan tool with key on and engine off — if voltage is stuck at or near 5 V across the full pedal range, the fault is active and a short-to-reference is the prime suspect.
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3
Disconnect the TPS/APP sensor connector and re-check B-channel voltage at the harness side with a multimeter; if the voltage remains high with the sensor unplugged, the short is in the wiring harness, not the sensor.
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4
If voltage drops to zero or floating when sensor is unplugged, reconnect and measure the sensor's B-channel output directly — a reading stuck high with the harness electrically clean confirms the sensor itself is faulty.
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5
Inspect the connector body closely for bent, pushed-back, or corroded pins that could be bridging the signal and reference voltage pins; also inspect along the harness length for chafing near hot or sharp surfaces.
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6
Verify the ECM reference voltage supply is within 4.9–5.1 V; an over-voltage supply could push a healthy sensor's B-channel above the threshold.
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7
Replace the TPS or APP sensor once wiring and reference supply are confirmed good, ensuring the replacement is seated correctly and torqued to specification.
Related powertrain codes
- P0120 — Throttle Position Sensor/Switch A Circuit Malfunction
- P0121 — Throttle Position Sensor/Switch A Circuit Range/Performance Problem
- P0122 — Throttle Position Sensor/Switch A Circuit Low Input
- P0123 — Throttle Position Sensor/Switch A Circuit High Input
- P0124 — Throttle Position Sensor/Switch A Circuit Intermittent
- P0220 — Throttle/Pedal Position Sensor/Switch B Circuit Malfunction
Frequently asked questions
Why would a stuck-high sensor reading cause the engine to lose power rather than go to full throttle?
The PCM does not blindly trust a single stuck-high reading as a genuine wide-open-throttle command. It cross-checks the B-channel against the A-channel, the MAP/MAF sensors, and idle logic. When B is stuck high but A indicates a different position and the other air-load data disagrees, the PCM flags a sensor conflict and falls back to a failsafe mode — deliberately limiting power rather than risk acting on a falsely commanded wide-open throttle.
Can P0223 appear without any drivability symptoms?
Rarely. Because the B-channel at maximum voltage is far outside the correlated range with the A-channel, the PCM will almost always activate a reduced-power or limp strategy. A very brief or marginal over-voltage event just above the threshold might store the code as a pending fault without immediate limp mode, but a persistent stuck-high reading virtually always affects drivability noticeably.
How do I tell if the fault is in the wiring or the sensor?
Unplug the sensor connector and measure the B-channel signal voltage at the harness-side pins (not the sensor pins) with a multimeter. If the voltage is still high with the sensor disconnected, the fault is in the wiring — likely a short between the signal wire and the reference or battery supply wire. If the voltage goes to zero or reads correctly, the fault is internal to the sensor and the sensor should be replaced.
Is P0223 more serious than P0222?
Both codes indicate a B-channel out-of-range fault and carry similar severity in terms of PCM response — both typically trigger limp mode. P0223 (stuck high) is sometimes considered marginally more concerning because a shorted-to-reference wire carries a small theoretical risk of the PCM misinterpreting the signal as a throttle command, whereas P0222 (stuck low) more clearly reads as a missing signal. In practice both should be diagnosed and repaired promptly.
Disabling P0223 in software
RaceTune can permanently disable P0223 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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