ACCELERATOR CALIBRATION

I have found that the acceleration of my 2019 4WD 1,5dci Renault Duster is about 35% slower than specified. While searching on the internet for possible causes of the reduced power output, I found a procedure for recalibrating the throttle pedal, and was very surprised to find this did indeed cure the problem!

The procedure takes less than a minute and restores power output to the specified level but is, unfortunately, not permanent. Recalibration is again required after a few days.

The problem was reported to the agents during a recent service; however, the matter remains unresolved. No warning lights come on. The car is still under warranty. Can you advise on the best course of action? JOHN HOLTZHAUSEN

Via email

Before responding, it might be appropriate to clarify to readers that on modern vehicles, the accelerator no longer physically opens the throttle via a cable. The accelerator is connected to a position sensor and its position – the driver’s wish – is just one of many inputs into the engine management system, which controls fuel flow. The position sensor sometimes features different maps to provide different levels of response: the eco mode on some vehicles and the desensitised throttle in “crawl” mode on some 4x4s are examples.

In this case, it’s clear the problem is occurring somewhere between the input from the accelerator position sensor to the management system and then to the throttle valve actuator. With a repetitive problem – which is responding to a recalibration – it is probably necessary to request the dealer to carry out a proper plug-in diagnosis, preferably when the engine feels down on power

– tech editor.