Powertrain, generic · Vehicle speed, idle control and auxiliary inputs
P050C Cold Start Engine Coolant Temperature Performance
Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo
P050C is documented only on Bosch ME9 in the Saab 9-3 V6 2.8 turbo: a cold-start plausibility check of the coolant temperature sensor. After a long stop coolant and intake air must read about the same; the code sets if coolant is more than 10 °C below or 15 °C above intake air, once per trip with the warning lamp. A wrong coolant reading distorts cold-start enrichment and can run the fan on a cold engine. The common reading 'coolant warms up too slowly' does not fit – that is P0125/P0128. GM, Ford and FCA do not use P050C.
Likely causes
Coolant temperature sensor drifting, wrong characteristic
Contact resistance or corrosion at the coolant or intake air sensor connector
Intake air temperature sensor reading wrong
Auxiliary heater or block heater not recognised, very short stop
Symptoms
- Check engine light on
- Rough running after a cold start
- Radiator fan runs with a cold engine
Repair estimate
DifficultyEasyDIY possible
Parts and labour€30–180
Time0.3–1.5 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
engine coolant temperature sensorintake air temperature sensorengine control module
Related codes
References: saabwisonline.com, saabwisonline.com, law.cornell.edu.