Open Loop (Engine Control Mode)
Open loop is an engine control mode in which fuel is set from stored maps without using oxygen sensor feedback.
What is Open Loop (Engine Control Mode)?
It is used during warm-up before the oxygen sensors are ready. It is also used at full load to protect the engine with a richer mixture. Live data on most scan tools shows whether the system is in open or closed loop. Modern engines enter closed loop within a short time after starting.
How it works
The control unit relies on sensor inputs such as temperature, air flow and load and ignores the oxygen sensor for a while.
Why it matters for your car
An engine stuck in open loop uses more fuel and may fail an emissions test. Faulty coolant temperature or oxygen sensors are common causes.
Other terms
- A/C Compressor
- AdBlue Crystallisation (Urea Deposits)
- Air Quality Sensor
- Anti-roll Bar
- Car Shampoo
- Diode
- Drive-by-wire (Electronic Throttle)
- Duty Cycle
- Gear Whine
- Grand Tourer (GT)
- Ignition Switch
- Kei Car
- Lean Mixture
- Night Vision Assist
- Number Plate Cloning
- Primer (Primer Surfacer)
- Reinforced Tyres (XL, Extra Load)
- Saloon (Sedan)
- Three-Cylinder Engine
- Wastegate