Daimler, Volkswagen and BMW are a three-way battle to offer incentives to get aging vehicles off German roads and prevent a crackdown on scandal-tainted diesel fuel.

Bloomberg said VW and Audi are the most generous with as much as EUR10,000 (US$11,800) off some models, according to company statements Tuesday. Daimler’s Mercedes-Benz luxury marque is offering a EUR2,000 incentive Europe-wide on new diesel or plug-in hybrids while its Smart city car unit will pay EUR1,000 to buyers of an electric model. Customers can trade in cars from any maker that meet now-outdated Euro 1 to Euro 4 emissions standards.

Bloomberg noted the incentives are among pledges made by the automakers at a meeting last week with German political leaders. The manufacturers agreed to update pollution control software on as many as 5.3m diesel cars meeting Euro 5 and Euro 6 regulations, a project estimated to cost EUR500m industry-wide and to take trade-ins of older models that can’t be upgraded.

Volkswagen, Daimler, and BMW agreed last week to diesel vehicle software upgrades.

BMW last week offered up to EUR2000 to those who switch from an older diesel car to an electric model while VW now will add a further EUR1,000 to EUR2,380 on top of trade-in rebates if customers purchase a vehicle powered by batteries, hybrid electric-combustion drive or natural gas. Audi will also offer extra cash to buyers of a plug-in hybrid or electric E-tron auto.

VW’s sales chief Juergen Stackmann declined to tell Bloomberg how much the incentives will cost, beyond saying they’ll involve a “substantial million-euro amount”.

Daimler estimated that about 300,000 of its diesel cars with Euro 4 engines are on the road across Europe. If all customers returned to the manufacturer to replace those cars, that could cost the automaker some EUR600m, Bloomberg said.

According to Bloomberg, Frankfurter Allgemeine Zeitung reported on Tuesday Porsche was looking at whether to stop offering diesel versions of its cars starting with the next generation Cayenne SUV which it will unveil later this month.

A decision hasn’t been made yet, a Porsche spokesman told Bloomberg.