The campaign will break on the first day of the charge, 17 February, with a heavyweight two-week burst across major 96-, 48- and six-sheet poster sites within the charging zone. It will be supported by radio spots on London stations. Media planning and buying is through MindShare.
The creative work incorporates the congestion scheme's "C" logo, with one execution reading "No charge" and another "Exempt". LPG-powered vehicles are exempt because the fuel is less polluting than petrol or diesel. It is also half the price per litre.
A supporting print campaign will run in motoring titles until April.
The campaign was written and art directed by Peter Sugden and Terry Holben.
Steve Parker, the director of commercial vehicles at Ford of Britain, said: "It's an ideal opportunity to promote the twin benefits of the Transit LPG at a time when public awareness of the congestion charging will be at its peak."