Sensors and engine management
The engine control module reads sensors and controls fuel, spark, timing, and idle. A crankshaft sensor tells it engine speed and position, and a camshaft sensor tells it which stroke each cylinder is on. A mass air flow or manifold pressure sensor tells it how much air is coming in. Temperature, oil pressure, knock, throttle position, and oxygen sensors fill in the rest. Many other modules on the vehicle, such as the transmission and body controllers, use sensors of their own.
Common parts
| Ref | Part group |
|---|---|
| SE-01 | Engine and powertrain control modules |
| SE-02 | Crankshaft and camshaft position sensors |
| SE-03 | Mass air flow and manifold absolute pressure sensors |
| SE-04 | Coolant and intake air temperature sensors |
| SE-05 | Throttle position sensors and accelerator pedal sensors |
| SE-06 | Knock sensors |
| SE-07 | Oil pressure and oil level sensors and sending units |
| SE-08 | Variable valve timing solenoids |
| SE-09 | Vehicle speed sensors |
Finding the right fit
Sensors that look alike often have different connectors, resistance ranges, or tip lengths. Match the engine, and for position sensors also the location, such as intake or exhaust camshaft, or bank one or bank two. Control modules usually need programming to the vehicle’s VIN, and some need security setup with dealer-level tools. Buying a used module from another vehicle may not work without that step.
Symptom to part
| What you notice | Usually points at | Check first |
|---|---|---|
| Stalls when hot, restarts when cool | Crankshaft position sensor | Watch the RPM reading while cranking |
| Hesitation, poor economy | Dirty or failing air flow sensor | Inspect for debris; check the intake for leaks after the sensor |
| Temperature gauge reads wrong | Coolant temperature sensor or its wiring | Compare the scan tool reading with the actual engine temperature |
| Code names a circuit, not a part | Wiring, connector, or ground | Check the connector and the circuit before buying the sensor |
Before you order
Start with the year, make, model, and engine, then narrow it down with the trim, drive type, and any option the part depends on. The VIN is the most reliable way to do that, because many parts catalogs and dealer counters decode it to the exact build. If the old part is in hand, its original-equipment number is the best cross-reference. Aftermarket brands publish their own numbers and usually list the original number they replace. Two listings that both say they fit can still differ, so compare the photos, connectors, mounting points, and the notes in the listing. The find the right part guide covers this step, and the all makes reference lists each maker’s official parts catalog.
Once you know the part number, compare the same number across stores. Look past the first price at the core charge, shipping, the return window, and what the warranty covers and who honors it. A remanufactured part, a new aftermarket part, and an original-equipment part can each be the right choice, but they are not the same purchase. The compare prices and warranties guide walks through what to read. Prices on PartIndex carry the date they were recorded, so confirm the current price and fitment with the retailer before you buy.
Disconnect the battery before you unplug a control module. Static electricity can damage modules, so touch bare metal on the body before you handle one. Do not probe connectors with tools that can spread the terminals.