Saab 9-5 P0116 P0420

Question

I have the following codes.

P0116*
P0420

Why is there a * next to the first code?

Answer 1

P0116 Engine coolant temperature sensor circuit

P0420 Catalyst system below efficiency

That * depends on you scan tool , As for the code condition , The purpose of the CK ENG LT is to protect the catalytic convertor and the catalytic convertor is to protect the enviroment, The engine PCM needs to to a proper engine coolant temperature this is for fuel control to adjust proper fuel mixture. Without a properly working coolant temperature the fuel control is out of balance and the catalytic can not do its intended job.The PCM will also subsitutue a coolant temperature value to maintain proper fuel control. P0116 can be from a improper coolant thermostat, to a low coolant level to a coolant leak.P0420 can also be the result of a malfunctioning coolant temperature condition