Investigating P0120 in Your 2024 Audi Q5
When the EPC (Electronic Power Control) light illuminates alongside the check engine light in your 2024 Q5, our investigation points to a throttle position sensor circuit malfunction. This second-generation Q5 runs the EA888 2.0T engine on Audi's MLB Evo platform, where the throttle body is a fully integrated electronic unit with the TPS built directly into the assembly. P0120 means the ECU is receiving erratic or out-of-range signals from this sensor circuit.
Symptoms You're Likely Noticing
- EPC warning light on the dashboard (amber)
- Check engine light illuminated
- Limp mode — engine limits power to protect drivetrain
- Rough or unstable idle
- Hesitation or surging during acceleration
- Engine may stall at low speeds or stops
Common Causes (Ranked by Likelihood)
1. Carbon Buildup on Throttle Body
The direct-injection EA888 is prone to carbon deposits on the throttle plate and bore. This buildup interferes with the throttle position readings, causing the ECU to flag P0120. A thorough cleaning often resolves the issue on low-mileage 2024 models.
2. Throttle Body Assembly Failure
The Bosch electronic throttle body on the Q5 integrates the TPS, motor, and throttle plate into one unit. Internal motor or sensor failure requires full throttle body replacement. On a 2024 model, this should be covered under warranty.
3. Wiring Harness or Connector Issue
Corroded pins, chafed wires, or a loose connector at the throttle body can produce intermittent P0120 codes. The Q5 engine bay can trap moisture, accelerating connector corrosion.
4. ECU Communication Error
A software glitch or CAN bus communication fault between the throttle body and ECU can trigger P0120. Audi may have a software update or TSB addressing this on 2024 models.
5. Accelerator Pedal Position (APP) Sensor
Though less common, a failing APP sensor sends conflicting signals that the ECU interprets as a throttle position circuit fault.
Diagnostic Steps
- Scan with VCDS or OBD-II for freeze frame data and companion codes
- Inspect throttle body connector for corrosion or damage
- Check throttle body for carbon buildup — clean if present
- Monitor live TPS voltage data (should sweep smoothly 0.5V–4.5V)
- Test wiring continuity between throttle body and ECU
Repair Costs
- Throttle body cleaning: $150–$300
- Throttle body replacement (Bosch OEM): $500–$900
- Wiring repair: $150–$350
- ECU software update: $150–$250
- APP sensor replacement: $200–$400
Can I Drive With P0120?
This is a safety-critical code. Your Q5 will likely enter limp mode, severely limiting power and speed. Do not attempt highway driving in limp mode. Have it towed or drive cautiously to the nearest Audi dealer — your 2024 Q5 is under the 4-year/50,000-mile warranty.
DIY vs Professional
For a 2024 Q5 still under warranty, take it to the Audi dealer. The repair will likely be covered at no cost. Attempting DIY work could void warranty coverage. If out of warranty, throttle body cleaning is feasible for experienced DIYers, but replacement and software calibration require VCDS or ODIS dealer tools.
Frequently Asked Questions
What does P0120 mean on an Audi Q5?
P0120 indicates the throttle position sensor circuit is sending abnormal signals to the engine control unit. On the Q5, the TPS is integrated into the electronic throttle body and cannot be replaced separately.
Is P0120 dangerous to drive with?
Yes. Throttle control is safety-critical. The vehicle will typically enter limp mode, limiting speed. Get it diagnosed immediately — do not ignore this code.
How much does it cost to fix P0120 on an Audi Q5?
Most repairs range from $150 for a throttle body cleaning to $900 for a full throttle body replacement. Your 2024 model should be covered under Audi's factory warranty.
Will a P0120 code clear itself?
It may temporarily clear if caused by an intermittent wiring issue, but it will return. The underlying cause must be addressed — this is not a code to ignore.