Parts for your 2010 Audi Q5-Temperature sensors

2010 Audi Q5 temperature sensors: what they do and when to service them

Based on technical sources including the Audi ElsaWin workshop manual, the Audi Self-Study Programme for the 2.0 TFSI (SSP 397) and 3.0 V6 TDI (SSP 351), and the Audi/Volkswagen ETKA parts catalogue, the 2010 Audi Q5 is fitted with multiple temperature sensors across the engine, transmission and climate systems. So yes—temperature sensors are absolutely relevant to this model.

On a 2010 Q5, temperature sensors help the car manage fuelling, timing, emissions, cooling and cabin comfort. The engine control unit relies on them to decide how much fuel to add on a cold morning, when to kick the radiator fans in under the bonnet on a hot day, and how to protect the engine under load. Climate control uses them to keep the cabin comfy without you fiddling with the dials all the time.

• Engine coolant temperature (ECT) sensor: core input for warm-up, fan control and gauge behaviour.
• Intake air temperature (IAT) sensor: often integrated with the MAF, trims fuelling and ignition.
• Engine oil temperature sensor: supports protection strategies and (on some variants) driver info.
• Ambient air temperature sensor: feeds HVAC and the outside-temp display.
• Automatic transmission fluid temperature sensor: manages shift quality and protection.
• On TDI variants: exhaust gas temperature (EGT) sensors for turbo and DPF management.

There’s no fixed replacement interval—these sensors are replaced on condition. Common red flags include hard cold starts, high or hunting idle, the gauge reading oddly, radiator fans running constantly, poor fuel economy, or a check engine light with codes like P0115–P0119 for the ECT. A quick scan with a diagnostic tool and comparing live data to actual conditions saves guesswork.

During routine servicing, it’s smart to visually check connectors and wiring for brittleness, corrosion or coolant staining, especially around the ECT’s O-ring and retaining clip. Avoid blasting connectors with a pressure washer. If the IAT lives in the MAF, only clean with proper MAF cleaner—never touch the element. When you’re already in the cooling system (say, doing a thermostat or coolant flush) on a high‑kilometre Q5, many techs proactively replace the ECT because they’re inexpensive and age-sensitive.

Replacing an ECT? Let the engine cool, relieve pressure, catch and reuse/replace coolant as required, fit a new O-ring and clip, then refill with the correct G12/G13 mix and bleed the system. Ambient sensors usually sit behind the front grille/bumper and can be swapped with basic tools. After any replacement, clear codes and confirm normal readings on a scan tool. Sticking with quality OEM-equivalent sensors helps avoid wonky readings that can cause bigger headaches.

Popular questions

Where is the coolant temperature sensor on a 2010 Audi Q5?
On the 2.0 TFSI, the ECT is typically mounted at the coolant outlet/thermostat housing on the side of the cylinder head, under the engine cover and intake plumbing. On the V6 petrol and TDI variants, it’s near the thermostat housing as well. Access varies a bit by engine, but it’s usually reachable with basic hand tools once the cover and some ducting are out of the way.

Do you need to bleed the cooling system after replacing the ECT sensor?
Yes. Any time the cooling circuit is opened, refill with the correct G12/G13 coolant mix, run the heater on hot, and bleed air per the workshop procedure. Watch for stable heater output and normal fan operation, then recheck the level after a short drive once it’s cooled down.

Can a bad temperature sensor cause poor fuel economy or the fans to run constantly?
It can. If the ECT reports the engine as colder or hotter than it really is, the ECU may enrich fuelling or run the radiator fans at full tilt. You might see rich running, rough starts, odd gauge behaviour, and a check engine light. A quick scan and live-data check will confirm.