If the defect described above is determined in conjunction with various error codes associated with the lambda sensors upstream and downstream of the catalytic converter, the cause could be the ingress of moisture into the engine wiring harness. The resulting corrosion on the plug connections can trigger the various error entries. A critical point which is generally diagnosed as the cause is the plug connection on the thermostat.
As part of the fault diagnostic process on these vehicle models, the wiring harness should be checked; if necessary, replace the thermostat and the associated connector.
Repair note
The problem has been detected by the vehicle manufacturer and prevented by a technical change in production effective from model year 2011.
Please observe the vehicle manufacturer's repair and maintenance instructions in this regard.
This defect may also occur in other models from this manufacturer with the same engine.
Important safety notice
The following technical information and tips for practical use have been set up by HELLA in order to offer professional support to automotive workshops in their daily work. The information available here on this website is only to be used by appropriately trained specialist staff.
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