Possible causes

– Low engine coolant level
– Faulty Thermostat
– Leakage from sealing portion of thermostat
– Engine coolant temperature sensor

Tech notes

If no coolant leaks are present, replacing the thermostat usually takes care of the problem.

When is the code detected?

The P1126 Code is detected when the engine coolant temperature does not reach to specified temperature even though the engine has run long enough.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1126 2000 INFINITI G20 Description

Engine coolant temperature has not risen enough to open the thermostat even though the engine has run long enough. This is due to a leak in the seal or the thermostat open stuck.