PARIS/MILAN, Feb 7 (Reuters) - Fiat Chrysler vehicles were allowed to skip key tests for illegal engine software during Italy's main emissions-cheating investigation in the wake of the Volkswagen scandal, according to the transport ministry's own report.
The report, presented to a European parliamentary committee in October but never officially published, will be seized upon by environmental groups pressing MEPs to vote on Thursday for tougher EU oversight of vehicle testing by national authorities.
"It's imperative that we break this cosy relationship between national testing authorities and their domestic carmakers," said Julia Poliscanova, a vehicle emissions specialist at Brussels-based campaign group Transport & Environment. "This problem is at the heart of Dieselgate."
The Italian report may raise questions for Fiat Chrysler (FCA) as it faces a U.S. criminal investigation for alleged emissions manipulation and German accusations that it, like VW , used "defeat devices" to confound nitrogen oxide (NOx) tests.
FCA on Monday became the third carmaker after VW and Renault to be referred to French prosecutors over the scandal. The Italian-American company denies breaking any laws, a spokesman reiterated, declining further comment.
The ministry findings, which have been circulated by some Italian opposition politicians and examined by Reuters, include complete sets of data for eight diesel cars made by BMW, Ford, Mercedes-Benz, Volkswagen and GM's Opel.
But for three of the seven FCA models also investigated - a Jeep Cherokee 2.0, Alfa Romeo Giulietta 1.6 and Lancia Ypsilon 1.3 - results are missing from an on-road measurement phase and a reversed version of the EU's standard "NEDC" lab test.
All seven FCA models also lack data for an "Artemis" test that adjusts the EU lab regime to reflect urban driving styles. The three skipped protocols are typically used to help unmask defeat devices by preventing them from detecting the test.
No explanation for the missing FCA results was offered in the document. But transport ministry spokeswoman Luisa Gabbi told Reuters a "new definitive version" had been drafted to include more data for FCA models following further tests, and would be published in coming weeks.
Following VW's exposure in 2015 for U.S. diesel test-cheating, several European countries launched their own investigative test programmes.
Their results revealed on-road NOx emissions as high as 15 times the regulatory limits, as well as the widespread use of defeat devices that reduce exhaust treatment in some conditions.
Carmakers including Renault, GM and Fiat have broadly invoked an EU legal loophole that allows such software only when it is necessary for safety or engine protection. All deny breaking the law.
In German and French testing, a Jeep Cherokee 2.0 litre similar to the model overlooked by Italian engineers emitted between 5.3 and 9.9 times the legal NOx limit under modified EU test cycles conducted in the lab or on the road.
Independent road testing of a Fiat 500L with the same 1.6-litre engine as the omitted Alfa Giulietta measured NOx levels more than 5.6 times the statutory 180 miligrammes per kilometre for Euro 5 engines, according to UK-based Emissions Analytics.
According to the Italian report, the FCA models were all analysed in Fiat's own labs under the supervision of ministry officials, while all other models were tested at an independent Istituto Motori facility.
The draft regulation before MEPs would bolster EU supervision of government testing authorities to address perceived conflicts of interest when they inspect and certify the cars of their own national manufacturing champions.
Brussels would get powers to carry out vehicle spot-checks and allow national authorities to peer-review one another's decisions. Under current rules, a vehicle certification is valid EU-wide but can be revoked only by the country that issued it.
Lawmakers on the European Parliament's internal market committee are expected to approve the draft with only minor amendments on Thursday, setting the stage for a plenary vote.
The European Commission, which drew up the proposals last year, is mediating in a related dispute after Germany accused Italian regulators of failing to act on evidence that FCA models including the Fiat 500X use banned defeat devices.
A spokeswoman for the EU executive declined to comment on the Italian diesel report but emphasized the need for change.
"Member states have so far wanted to keep exclusive responsibility," Lucia Caudet said. "But this system has failed." (Additional reporting by Alissa de Carbonnel in Brussels and Stefano Rebaudo and Agnieszka Flak in Milan; Writing by Laurence Frost; editing by Susan Thomas)