Trajet Charge Air Temperature Sensor Issue

The symptoms you describe strongly suggest a fault within the charge air system. The error code stored in the ECU will provide valuable insight. The reduced power and whistling/hissing noise are classic indicators of a charge air leak, often stemming from a faulty sensor connection. However, the sensor itself might not be the culprit. Consider the system as a chain; a weak link anywhere affects the whole. Before replacing the sensor, meticulously inspect the cable and plug connection. Are there any signs of damage, corrosion, or loose connections? A faulty connection can mimic a defective sensor. Is the temperature gauge behaving erratically? Does it fluctuate wildly or remain fixed at an implausible value? This behaviour would further implicate the sensor circuit.

I checked the temperature gauge, and I don't see any wild fluctuations. It seems relatively stable. You mentioned inspecting the cable and plug connection. Could you elaborate on how to best perform this inspection? What exactly should I be looking for?

Given the stable temperature gauge reading, the sensor itself is less likely to be defective. The inspection of the cable and plug connection necessitates meticulous scrutiny. Firstly, visually examine the cable for any signs of physical damage – cuts, abrasions, or exposure of the internal wires. Then, focus on the plug connection. Disconnect the plug and inspect the pins for corrosion or bending. Use a contact cleaner to remove any accumulated debris or oxidation. Ensure a secure and tight fit when reconnecting the plug. If, after this meticulous inspection and cleaning, the problem persists, it might be prudent to consult a qualified technician. The error memory should be read to confirm the origin of the error. Continuing to drive the vehicle with a charge air system fault could potentially lead to further engine damage. Based on your description, I would recommend a visit to a workshop.

Following your advice, I took my Trajet to a local workshop. As you suspected, the issue was indeed with the cable or plug connection of the charge air temperature sensor. The mechanic cleaned the contacts and secured the connection. The check engine light is now off, the engine power is back to normal, and the whistling noise has disappeared! The repair cost was 95€.