Technical Check engine and drive mode disabled

[mrbug63]

I have a 2016 500x 2.4 . Have a code P 0126 and P0128 . Thermostat to replace ? And act intermittently shuts off on start up . RePlaced battery , after a while chk engine comes on + drive modes disabled. Then sometimes no start , no electronics . Disconnect negative cable then reconnect and I can restart the car . ?????? Any ideas ????

 

[daugaard47]

Having same issues. Did you ever find out what was going on?

 

[s130]

P0125	Insufficient Coolant Temperature for Closed Loop Fuel Control; ECT Excessive Time to Closed Loop Fuel Control
P0126	Insufficient Coolant Temperature for Stable Operation
P0128	Coolant Thermostat Malfunction

The above codes suggest a value / range error as opposed to a sensor failure. The following ones suggest a fault temperature sensor.

P0115	Engine Coolant Temperature Circuit Malfunction
P0116	Engine Coolant Temperature Circuit Range/Performance Problem
P0117	Engine Coolant Temperature Circuit Low Input
P0118	Engine Coolant Temperature Circuit High Input
P0119	Engine Coolant Temperature Circuit Intermittent

So to me this *possibly* suggests that the car thinks it is not running in the correct temperature range. Now this could be down to a thermostat issue, other flow blockage, poor water pump, clogged up radiator with dead flies, leaves, dirt, etc.

However the "sometimes no electrics", "no start", etc. suggests a possible wider fault like a poor earth connection possibly to the engine block.

I would start by checking the coolant system temperatures and flows. This can be basically done by monitoring the top and bottom radiator hoses. From cold one (usually top) will gradually get hotter and hotter. The other will get warm and then will suddenly get hot as the thermostat opens. Then you leave and wait to check the cooling fan cuts in. Getting a temperature read would be a bonus.

See these links:

https://www.obd-codes.com/p0126

https://www.obd-codes.com/p0128