How to Test CPS Sensor (Crankshaft Position Sensor)

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How do I test a CPS sensor?

To test a CPS (Crankshaft Position Sensor), use a multimeter to check for proper resistance or voltage signals between sensor terminals.

Most CPS sensors should read between 200–2,000 ohms, but always confirm with your vehicle’s service manual. You can also test for signal voltage while cranking the engine—look for voltage pulses.

Watch Now: YouTube Video: How to Test Crankshaft Position Sensor with a Multimeter

How to Test a CPS Sensor – Step-by-Step Instructions

Tools You’ll Need:

  • Digital Multimeter
  • Repair Manual or Wiring Diagram
  • Back-probe pins (for non-intrusive testing)
  • Safety Gloves

Method 1: Resistance Test (Sensor Unplugged)

  1. Turn off the ignition
  2. Disconnect the CPS sensor plug
  3. Set multimeter to ohms (Ω)
  4. Place probes on the sensor’s pins
  5. Compare reading to vehicle specs (200–2,000Ω is common)

Method 2: Voltage Test While Cranking

  1. Keep the sensor plugged in
  2. Set multimeter to AC voltage
  3. Back-probe the signal and ground wires
  4. Have someone crank the engine
  5. Look for pulsing voltage on the signal wire

Method 3: Continuity Check

  1. Turn off ignition
  2. Set multimeter to continuity mode
  3. Test between pins for open or short circuits
  4. If no beep or continuity reading, sensor may be bad

Expert Tips

  • Always use manufacturer-specific specs
  • Don’t test sensors near magnets or spark plug wires to avoid false readings
  • If unsure, swap with a known good sensor (if available)

Frequently Asked Questions

How do I test a 3-wire crankshaft position sensor?

  • Step 1: Identify the power, ground, and signal wires
  • Step 2: With the ignition ON (engine off), check voltage on the power wire (~5V)
  • Step 3: Ground should show 0V
  • Step 4: Crank engine and measure the signal wire for pulsing voltage (using AC setting)
  • Tip: Use a back-probing method to avoid wire damage

How do I test a CPS sensor with a multimeter?

  1. Remove the sensor from the vehicle
  2. Set multimeter to resistance (Ω)
  3. Place probes on the terminals
  4. Compare the reading to manufacturer specs
  5. If resistance is too high or reads “OL” (open loop), it’s likely faulty

Can a bad CPS sensor damage my engine?

While it won’t cause physical engine damage, it can lead to misfires, poor combustion, or complete engine shutdown, especially at highway speeds.

What are the symptoms of a bad CPS sensor?

  • Hard starting or no-start condition
  • Engine stalls or misfires
  • Check Engine Light (CEL) may turn on
  • Poor fuel economy and acceleration
  • Rough idle or jerking while driving

How often should CPS sensors be tested?

Only test when symptoms appear or during diagnostics. They’re not regular maintenance items but should be inspected after 100,000+ miles.

What’s the cost to replace a crankshaft sensor?

It typically ranges between $75–$250, including parts and labor, depending on your car model and service provider.

Note: You can easily convert between different energy units with our free online energy conversion calculators. 

Testing a CPS sensor is simple with the right tools and steps. Whether your engine won’t start or runs rough, the crankshaft position sensor is a critical part of the ignition system. Accurate testing can save you costly guesswork and unnecessary repairs.

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