P0128 Jaguar -

Question

Re:Jaguar XJ8 3.2l 2001.

Does this code affect or bias air fuel ratio control through the ECU in any way, i.e. hold it in start up fuel rich mode with resultant higher exhaust gas emissions?

Answer 1

P0128 Coolant thermostat malfunction

Yes this code affect the air - fuel ratio, when the engine is cold it needs more fuel , as the engine warms up it needs less, this will result in rich running condition and higher exhaust emission.