ICE-31 — Engine Sensors

ASSUMPTION — This lesson covers sensors functionally; exact operating ranges are not given.

In this lesson you will learn:

• The basic sensors and what they measure
• Their roles in control
• The effect of a sensor fault

1. The Sensors’ Role

Sensors are the ECU’s “eyes and ears”: they measure engine state and provide the inputs for control decisions.

FACT — The ECU reads air, fuel, speed, temperature and combustion quality from sensors and manages the actuators accordingly.

2. Basic Sensors

Sensor	Measures
Crank position	Engine speed and crank angle
Cam position	Valve phase (cylinder sync)
MAF / MAP	Air mass flow / manifold pressure
Lambda (O2)	Exhaust oxygen (mixture richness)
Knock	Knock vibration
Coolant temperature	Engine temperature
Accelerator pedal position	Driver torque request

FACT — Crank and cam position sensors are critical for injection/ignition timing synchronization; without them the engine cannot run.

3. Sensor Faults

FACT — On a sensor fault, the ECU typically enters a fallback/limp-home strategy and sets an OBD DTC (ICE-42).

4. Summary

• Sensors are the ECU’s measurement layer.
• Crank/cam position is critical for sync.
• MAF/MAP measure air; lambda measures mixture; knock measures combustion quality.
• On fault, the ECU falls back to a limp strategy.

5. Sources

• Bosch, Gasoline-Engine Management and Diesel-Engine Management

Next Lesson

• ICE-32 — Engine Actuators.