Parts for your 2018 Audi Q5-Temperature sensors

2018 Audi Q5 temperature sensors: what they do and when to replace them

Temperature sensors are absolutely used on the 2018 Audi Q5. Audi factory literature and technical sources—such as the Audi Q5 (FY) Self‑Study Programme for the model launch, the EA888 Gen 3 engine Self‑Study Programme, the official ELSA/erWin repair information, and ETKA parts listings—show multiple temperature sensors fitted for engine management, transmission, and climate control. They’re fundamental to how the car starts, drives and keeps its cool in Aussie and Kiwi conditions.

On this Q5, the line‑up typically includes:

• Engine coolant temperature (ECT) sensor
• Intake air temperature (IAT) sensor (often combined with the MAF/charge system)
• Ambient/outside air temperature sensor (front bumper area)
• Evaporator and refrigerant temperature/pressure sensors for the air‑con
• Exhaust gas temperature (EGT) sensors on TDI models
• Transmission fluid temperature sensing within the mechatronics (auto)

What do they actually do? In short, they feed live data to the engine and transmission computers and the HVAC controller so the Q5 can adjust fuelling, ignition, turbo strategies, fan speed, air‑con performance and emissions. Cold starts, hot‑day traffic, mountain descents—these sensors let the car adapt on the fly and protect itself from overheating.

When a temperature sensor plays up, the tell‑tales can be sneaky: slow or rich cold starts, high idle, lousy fuel economy, fans roaring, air‑con cutting out, or an outside temperature reading that’s clearly off. The dash might throw a check‑engine light with codes such as P0116/P0118 (ECT), P0113 (IAT), P0071/P0073 (ambient), or EGT‑related faults on TDI variants.

Replacement and maintenance are straightforward but best done properly. These sensors aren’t a scheduled service item—inspect and test them during routine servicing. A scan tool can compare live values to reality (e.g., coolant temp vs. a cold engine, ambient vs. workshop temperature). Keep connectors clean, wiring secure and away from hot or moving parts. For replacements, use quality OE‑spec parts, fit new O‑rings/seals, and avoid thread tape unless the repair manual specifies it. If the ECT is removed, capture and top up coolant and bleed the system per the repair guide. Clear fault codes and road‑test to confirm stable readings.

A note on locations: on the 2.0 TFSI, the coolant temp sensor is typically integrated near the thermostat/coolant housing, the ambient sensor sits behind the front grille or bumper, HVAC sensors hide in the airbox/evaporator area. TDI models add EGT sensors near the turbo/DPF. Always check by VIN/engine code against Audi’s repair info.

Look after the temperature sensors, and the Q5 will return the favour with smooth manners, better economy and solid reliability across long kilometres.

Popular questions about 2018 Audi Q5 temperature sensors

Where is the engine coolant temperature sensor on a 2018 Audi Q5?
On most 2.0 TFSI models it’s mounted at or near the thermostat/coolant housing on the engine, while TDI variants commonly place it at a coolant flange by the cylinder head. Depending on engine code and market, the exact spot varies slightly. The best approach is to confirm location via the Audi repair manual for the specific VIN before ordering parts or pulling anything apart.

Can a dodgy ambient temperature sensor affect the air‑con?
Yes. The HVAC controller uses the outside temp to decide compressor engagement, fan speed and demist strategy. If the reading is way off, the system can disable cooling, cycle strangely, or blow warmer air than expected. Fixing a misreporting ambient sensor usually restores normal air‑con behaviour without deeper HVAC work.

Do temperature sensors need routine replacement?
There’s no fixed interval. Audi treats them as “as‑needed” items. During regular servicing, compare live data to actual conditions and inspect wiring and plugs, especially in high‑heat zones (near the turbo/exhaust) and the front bumper where road grime collects. Replace only when readings are out of whack, faults are stored, or physical damage is found.