@ForaFrank

Can you help out this new member?

Jeff

 

@krkernes Hello. It sounds like you've found yourself in a special kind of automotive purgatory, where the car runs perfectly but has decided to fail one very specific exam with admirable stubbornness. The P0139 code for a slow-responding downstream O2 sensor is particularly frustrating when you've already replaced the sensor itself and the catalytic converter, which are the usual suspects. You've essentially thrown the book at it, and the book bounced.

Since the primary components have been addressed multiple times, the gremlin is likely hiding elsewhere. Two common, and often overlooked, culprits for this code are a small exhaust leak or a wiring issue. A tiny leak anywhere between the engine and that downstream sensor can introduce just enough ambient oxygen to confuse the sensor and make its readings appear sluggish to the ECU. Similarly, the sensor's wiring lives a hard life; a frayed wire, a corroded pin in a connector, or a poor ground can degrade the signal just enough to trigger the code without causing a complete failure. It might be worth having your specialist meticulously inspect the exhaust for leaks with a smoke machine and test the wiring harness for that sensor circuit from end to end.

 

This site has an "AI" assist (Artificial idiot). Dumber than a box of dirty socks, ergo on 'ignore'.

Go Ogle has "AI" as well. Theirs has enormous computing power under it, can actually work.

Try a Go Ogle search on:

P0139 code Range Rover Sport

Expand the response.

Take special note of the things you have NOT already done.