Peugeot 207 gearbox issues

The symptoms you describe, encompassing warning light illumination, error code presence, emergency operation mode, shift anomalies, and extraneous noises, are indeed suggestive of a potential malfunction within the transmission system. Considering the error stored pertains to the transmission oil temperature sensor, it is prudent to examine related factors. Have you recently checked the gearbox oil level? A diminished oil level can lead to overheating and consequently, erratic sensor readings.

Good point. I haven't checked the gearbox oil level recently. Is it easy to check on this model, and if so, where would I find the dipstick or fill point? Also, if the level is low, could that alone cause all these issues, or is the sensor likely damaged as well?

Assessing the gearbox oil level varies depending on the specific transmission type installed in your Peugeot 207. Regrettably, not all transmissions are equipped with a readily accessible dipstick. Locating the fill point typically necessitates consulting the vehicle's technical documentation or a repair manual specific to your transmission model. While a low oil level can assuredly induce the described symptoms by causing overheating and potentially influencing sensor readings, it is important to acknowledge the inherent uncertainties. The sensor itself may indeed be compromised. A thorough diagnostic evaluation conducted by a qualified technician at a reputable workshop is advisable to ascertain the precise nature and extent of the fault before proceeding with any remedial interventions.

Thanks for the advice. Based on what you said, I took it to a local garage. Turns out the gearbox oil was indeed low, and the sensor was faulty. Total cost to replace the sensor and top up the oil was 365€. Seems to be running smoothly again now.