P0123 means the ECU sees TPS 'A' signal voltage above the upper threshold (typically 4.8V of the 5V reference). The computer ignores the throttle input and falls back to limp mode.
Scan your own car in about 60 seconds: see whether P0123 is really what it has, how urgent it is, and what the fix should cost. Free on iPhone and Android, on any ELM327 adapter.
Get Skanyx freeP0123 means the ECU sees TPS 'A' signal voltage above the upper threshold (typically 4.8V of the 5V reference). The computer ignores the throttle input and falls back to limp mode.
P0123 is a electrical-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P0123 and illuminates the check engine light.
If your vehicle has triggered P0123, you may notice one or more of these symptoms:
Here are the most common causes of P0123:
No - address this immediately. You can drive short distances, but most vehicles trigger limp mode with reduced throttle response. Sudden power loss is possible, so get it diagnosed before longer trips.
Follow these steps to pinpoint the root cause of P0123:
Repair costs for P0123 vary depending on the root cause and your vehicle. Here are typical estimates:
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0123 behaves differently depending on your vehicle. Select your car below for model-specific causes, known issues, and adjusted cost estimates:
1.4 TSI (CAXA/CAVD) and 2.0 TDI (CBEA/CJAA) throttle body connectors corrode where the harness routes near the coolant flange. VCDS measuring block 060 typically shows implausible angle-sensor 2 voltage.
5.4L 3V Triton trucks show P0123 with wiper-track wear inside the electronic throttle body.
E46 M54 and E90 N52 often log P0123 when the DK-Motor (throttle actuator) potentiometer starts failing. Genuine throttle bodies run €450-600 for parts alone, aftermarket VDO units around €250.
2AZ-FE and 2GR-FE ETCS-i throttle bodies (22030-28070 / 22030-31010) rarely fail early, but when P0123 appears the internal sensor is usually the culprit. Idle relearn required after cleaning or replacement.
8th/9th gen R18 engines occasionally log P0123 after aftermarket intake installs that disturb the throttle body connector. Honda's idle relearn (throttle body cleaned, KOEO 10 min with A/C off) is required after any TPS work.
These codes are often seen alongside P0123 or indicate related issues:
No. It's a hard electrical fault. The MIL might go out after several drive cycles without the fault recurring, but the underlying wiring or sensor issue almost always comes back within minutes.
Yes. It's a stored powertrain code with the MIL on, which is an automatic fail at any OBD2 inspection.
On older cable-throttle cars (mostly pre-2005) the TPS is a bolt-on €40-80 part. On drive-by-wire systems the sensor is integrated into the throttle body and you replace the whole assembly.
The PCM can't trust the throttle signal, so it ignores the pedal and holds the throttle at a fixed low opening (usually 1200-1500 RPM) to prevent unintended acceleration.
Yes, on nearly all drive-by-wire cars. Most brands need a specific idle/throttle relearn procedure (Toyota, Honda, VW, BMW all have their own). Skipping this leaves rough idle even after a good part is fitted.
A 15 euro Bluetooth adapter and a free phone app read the exact fault code a shop charges 30 to 100 euros to pull. Here is how to do it yourself in 5 minutes.
A failing throttle body shows up as a hunting idle, stalling, hesitation or limp mode. What the part does, the symptoms, the codes, and the repair cost.
Clean a sooty throttle body in under an hour for around 15 euros, handle the idle-relearn question honestly, and verify the fix with OBD2 live data.
A flashing check engine light means the engine is misfiring right now. Pull over and read the code: the fix is usually $80 to $400, the delay costs $1,500 up.
An unfamiliar symbol just lit up and you need to know whether to stop. Read the colour first, then find your symbol in the table: every one carries its verdict.
Your car logged P0123. Skanyx reads it on any standard Bluetooth OBD2 adapter, tells you whether it is safe to keep driving, and breaks down the likely repair so you know the number before a shop quotes you. Free on iPhone and Android, and you do not need to be a mechanic to read it.
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