Peugeot 407 Automatic Transmission Issue

I'm having trouble with my 2008 Peugeot 407 diesel with 249413 km on the clock. The transmission and check engine lights are on. The automatic transmission is in emergency mode, with strange gear shifts, slippage, and grinding noises. Diagnostics showed an error related to radiator oil pressure. I suspect a problem with the cable or plug connection. Has anyone else had similar issues?

4 comment(s)

I drive a Peugeot 407 and had a similar issue recently. Your symptoms sound familiar. For me, it was a faulty pressure sensor related to the oil cooler. The error codes initially pointed elsewhere, but that was it. Have you checked the sensor and wiring? Inspect the oil cooler for leaks or damage. Also, check the cooling fan is running properly.

Could you share the specific error codes you saw and the diagnostic steps you took to find the faulty pressure sensor? Were there any other symptoms besides what I mentioned?

I can't recall the exact error codes, sorry. It was related to the gearbox oil temperature. I had a local workshop look at it after checking the basics myself. If you're not confident with that level of diagnostics, take it to a workshop. It sounds very similar to what I had.

Following your suggestion and an inspection by a technician, the cable to the pressure sensor on the radiator was indeed defective, as I suspected. The repair, including replacing the cable and diagnostics, cost 95€. The car is now working as expected. Thanks for the help.

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