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GM's Opel denies understating CO2 emissions, fuel consumption

A reflection of the Opel stall is pictured during the media day at the Frankfurt Motor Show (IAA) in Frankfurt, Germany September 15, 2015. REUTERS/Kai Pfaffenbach

BERLIN (Reuters) - General Motors' Opel division has denied understating carbon dioxide (CO2) emissions and fuel consumption after a German media report said the carmaker's own tests on one of its models had shown strong deviations from official data.

German broadcaster ARD's Monitor documentary said on Thursday fuel consumption and CO2 emissions from Opel's Zafira 1.6 CDTi multi-purpose vehicle had been found to exceed the carmaker's certified data by 15 percent on average.

Three tests of the Zafira conducted by Opel in-house in late October revealed the discrepancies, Monitor said, adding its own tests of a 1.6-litre diesel-powered Zafira conducted at an emissions laboratory in Switzerland had found the model's CO2 emissions exceeded Opel's official data by about 20 percent.

"The CO2 values published by Opel are correct," the carmaker said.

"CO2 and consumption measurements are clearly defined by the law," it said, adding its findings on the CO2 levels of its models were monitored by independent inspectors.

Volkswagen's (VOWG_p.DE) admission to cheating diesel emissions on up to 11 million vehicles and CO2 certification data on about 800,000 cars has drawn attention to a wider pattern of legal test manipulation that stops short of outright cheating.

Germany's environmental lobby group DUH said in October the Zafira 1.6 CDTi had shown excessive emissions of nitrous oxide, a claim that was denied by Opel at the time.

French rival Renault last month said it contested findings by DUH that its Espace minivan released toxic diesel emissions 25 times over legal limits in tests carried out on DUH's behalf by a Swiss university.

VW is bracing for costs of at least 2 billion euros ($2.2 billion) from the CO2 cheating and has said it would foot the bill for extra taxes incurred by drivers as a result.

($1 = 0.9229 euros)

(Reporting by Andreas Cremer; Editing by Mark Potter)