Renault said on Tuesday it planned a software upgrade to cut nitrogen oxide (NOx) pollution from its diesel engines, which have come under fire for their relatively high emissions in the wake of the Volkswagen test-rigging scandal.<br />Following VW's exposure last September for using software "defeat devices" to cheat U.S. regulatory tests, the French carmaker has drawn public and investor scrutiny over its own emissions performance.<br />As of Monday's market close, Renault shares had fallen 14 percent since the Jan. 14 disclosure that investigators raided its offices this month over suspicions of emissions fraud - since roundly denied by company and government officials.<br />At 1236 GMT, the stock was up 1.8 percent at 75.50 euros.
