Volkswagen says 11 million vehicles worldwide are affected by the scandal that has erupted over its rigging of US car emissions tests.
The boss of Volkswagen's US business, Michael Horn, has admitted it "totally screwed up" in using software to rig emissions tests.
Last Friday, the US Environmental Protection Agency (EPA) said VW diesel cars had much higher emissions than tests had suggested and that software in several diesel cars could deceive regulators.
Here is selection of your views on Volkswagen's emissions-rigging scandal.
@SaratogaSprngs tweets that Volkswagen made the right move in admitting their mistake:
I am absolutely disgusted with this. I purchased my VW Golf due to the fantastic low emissions it was "claimed" to produce. Now I'm worrying that my car could be recalled. It's clear that VW would have happily carried on with this lie to its customers. The reason I chose such a car was because VW was a well-known respectable company but this could not be further from the truth. I want to know as soon as possible if my car has been affected and if so what are the actions from this point on. Oliver Ealey, Oxfordshire, UK
I purchased a VW Golf BlueMotion because low emissions are important to me. With hindsight it appears that the stats for the vehicle really were too good to be true. My confidence in the claims made by vehicle manufacturers is seriously diminished. I hope there will be more vigorous testing and greater transparency in future. I will also consider switching from a diesel to a hybrid. Robin Cole, Surrey, UK
@MihirBajoria tweets his disappointment in Volkswagen:
I drive a VW company car. One of my decisions when choosing it was the CO2 emissions figure. Simply because the higher it is the more tax I pay. What are VW and/or the UK government going to do if as a result of this apparent fraud by VW it means the official CO2 figures are reviewed and are higher than previously stated, meaning I have to pay more tax? David Turnbull, Edinburgh, Scotland
In July I took delivery of a new diesel Polo and my decision was based on the fact that the advertised fuel consumption / CO2 emissions were 75% of that of my 10-year-old diesel Polo. I was extremely disappointed to discover that there is actually little difference between fuel consumption in both vehicles. Had I known this, I would not have replaced the old one because it is in good condition. I have been a lifelong VW loyalist. Deeply disappointed. Eric de la Harpe, Oxfordshire, UK
Bob Smith in Scotland messaged on WhatsApp to say he chose Volkswagen to do his bit for the environment:
I purchased a VW SportWagen in 2009. My primary interests were in the durability, mileage and cleanliness of the clean diesel engine. I'm worried that any fix will affect these and make the car into the slow, problem prone VW diesel Rabbit of the 1970s. Byron Johnson, Texas, USA
At present we have a 2010 petrol Golf and a 2012 diesel Golf. I am extremely disappointed with this behaviour. We have had five VWs in the family. Pending on VW's resolve, we may never purchase another. We are already contemplating switching manufacturers. We purchased under a promise but we've been bold faced lied to. That sucks. What else are they lying about? Roy Greyeyes, Ottawa, Canada
@philinhongkong tweets being environmentally-friendly was not uppermost in his mind when he made his Volkswagen purchase:
We have five Volkswagens in the household, two of which are diesel. They have provided safe, frugal, and reliable transport for my family. As cars to live with they are light years ahead of Vauxhalls and Fords which we used to run. As a loyal Volkswagen customer I am, as you'd expect very, very, very disappointed. The brains, the resources, and innovation of this company alone could not allow this to happen, but it did. However, if any organisation can turn it round from this debacle it will be this one. Chandrin Katuwawala, Bedfordshire, UK
This afternoon we are seeing a VW dealer to close the deal for Passat which we viewed last week. We based the decision on how economical and environmentally friendly the car was. I don't know where it leaves us. Do we still go ahead or wait, in which case we will lose the special deal offered. It is a dilemma! Amirali Kanji, Hampshire, UK
Compiled by Andree Massiah