PARIS -- French prosecutors are investigating Renault over suspected cheating on vehicle exhaust emissions, a source at the Paris prosecutor's office told Reuters on Friday, sending shares in the automaker lower.
Three judges have been looking into the Renault matter since Jan. 12, the source said. Whether the prosecutor's inquiry is followed by a trial is for the judges to decide. They are focused on the public health implications of Renault's actions, the source told Reuters.
The opening of the judicial probe comes two months after the government passed findings of an investigation by the consumer fraud agency DGCCRF to the prosecutor's office.
Renault said it respected all laws concerning exhaust emissions and added that its vehicles did not have software allowing it to commit fraud in this area.
Renault had explained the NOx-cutting exhaust gas recirculation (EGR) in its top-selling diesel engines had been found to cause serious turbo clogging problems. Engineers responded by programming the EGR to shut down outside a narrow "thermal window" of air intake temperatures, 17-35 degrees Celsius (63-95 degrees Fahrenheit). While passing regulatory tests carried out at room temperature over short periods, the protocol sends NOx emissions sky-high on the road.
Renault shares fell 4 percent on Friday but had clawed back some ground, trading down 2.4 percent by mid-session versus a 0.5 percent rise on the STOXX Europe 600 Automobiles index
The French investigation into exhaust emissions by Renault engines and whether they broke emissions laws was launched in the aftermath of Volkswagen Group's diesel-emissions cheating scandal.
VW this week agreed to pay $4.3 billion in a settlement with U.S. regulators and the U.S. Environmental Protection Agency on Thursday accused Fiat Chrysler of also using software to conceal excess diesel emissions.
Fiat Chrysler CEO Sergio Marchionne rejected the allegations, saying there was no wrongdoing and the company never attempted to create software to cheat emissions rules by detecting when the vehicle was in test mode.