Gm Chevrolet Crankshaft Position Sensor P0335 Resistance Test with Multimeter

When your GM or Chevrolet sets a P0335 trouble code, the crankshaft position sensor is the first suspect. But replacing parts blindly gets expensive fast. Knowing how to measure the sensor's resistance with a multimeter gives you a real answer before you spend money on a new part or a shop visit. This procedure works on most GM 3.8L, 4.3L, 5.3L, 5.7L, and 6.0L engines found across Silverado, Tahoe, Suburban, Impala, Trailblazer, and other common Chevrolet models.

What does a P0335 code actually mean on a GM vehicle?

P0335 stands for "Crankshaft Position Sensor A Circuit Malfunction." The engine control module (ECM) monitors the signal from the crankshaft position sensor (CKP). When the signal is missing, erratic, or out of range, the ECM stores this code. On GM trucks and cars, this often leads to a no-crank or no-start condition, rough running, stalling, or intermittent misfires.

The CKP sensor tells the ECM exactly where the crankshaft is in its rotation. Without that information, the ECM can't fire the spark plugs or pulse the injectors at the right time. That is why a failed CKP sensor can completely disable the engine.

Why measure resistance instead of just replacing the sensor?

A new GM crankshaft position sensor costs between $20 and $80 depending on the vehicle. That sounds cheap until you factor in labor on some models where the sensor sits behind the harmonic balancer or near the transmission bellhousing. Resistance testing takes five minutes with a basic multimeter and can confirm whether the sensor itself is bad or whether the problem lies in the wiring, connector, or reluctor ring.

Measuring resistance also helps you catch problems that a simple visual inspection misses like an internal short or an open winding inside the sensor body. If the resistance checks out within spec, you know to focus your diagnosis elsewhere.

What tools do you need for this test?

Digital multimeter capable of reading resistance (ohms) in the 0–20,000 ohm range
Basic hand tools to access the sensor (usually a 10mm bolt on GM applications)
Clean cloth or contact cleaner to ensure good probe contact on the terminals
Factory service manual or repair database for your specific year and engine to verify exact resistance specifications

Where is the crankshaft position sensor located on GM and Chevrolet engines?

Location varies by engine:

4.3L V6 (S-10, Blazer, Astro) Typically on the driver's side of the engine block behind the harmonic balancer, near the crankshaft pulley.
5.3L / 6.0L V8 (Silverado, Tahoe, Suburban, Sierra) Usually on the rear of the engine block near the transmission bellhousing on the driver's side. Some later models moved it to the front timing cover area.
3.8L V6 (Impala, Grand Prix, Regal) Located on the front of the engine, mounted on the timing chain cover.
5.7L V8 (Corvette, Camaro, C/K trucks) Behind the harmonic balancer on the lower front of the engine.

On some GM V8 trucks, gaining access means removing the starter or working from underneath. On others, you can reach the sensor from the top with the air intake tube removed.

What is the correct resistance specification for a GM crankshaft position sensor?

Most GM crankshaft position sensors are variable reluctance (VR) type sensors. The typical resistance specification falls between 500 and 900 ohms at room temperature (around 70°F / 21°C). Some GM service manuals specify a tighter range of 585–825 ohms for certain engines.

A few newer GM vehicles use a Hall-effect type CKP sensor, which works differently. Hall-effect sensors have internal electronics and often show an open circuit (OL/infinite resistance) when measured with a standard ohmmeter. For these, you need to test reference voltage (usually 5V or 12V) and signal output instead of winding resistance.

Always confirm the exact spec for your vehicle's year, make, model, and engine in the factory service manual. Resistance ranges can shift slightly between model years and engine codes. You can find reliable specifications through a factory repair database like ALLDATA or your vehicle's service manual.

How do you measure the resistance step by step?

Turn the ignition off and remove the key. Disconnect the negative battery terminal for safety.
Locate the CKP sensor using the information above for your specific engine.
Unplug the sensor connector by pressing the locking tab and pulling it straight off. Inspect both the connector and harness for corrosion, bent pins, or damaged wires.
Set your multimeter to the ohms (Ω) setting. Choose the 2kΩ (2000 ohm) range for most GM VR-type sensors.
Touch the multimeter probes to the two sensor terminals inside the connector on the sensor side (not the harness side). It does not matter which probe goes to which terminal resistance is not polarity-sensitive.
Read the measurement. A healthy GM VR-type CKP sensor should read between approximately 500 and 900 ohms. Write down the exact number.
Compare to spec. If the reading is within range, the sensor windings are intact. If it reads OL (open/infinite), the internal winding is broken. If it reads near zero or very low, the winding is shorted internally.

For a more detailed walkthrough on using your multimeter for this test, see the complete CKP sensor multimeter testing procedure.

What if the resistance reads normal but you still have a P0335 code?

A resistance reading within spec does not always mean the sensor is good. Here is what else to check:

Air gap between the sensor and reluctor ring If the gap is too wide or too narrow (caused by a worn thrust bearing, damaged reluctor ring, or improper installation), the sensor may produce a weak or distorted signal even with good resistance.
Reluctor ring damage Cracked, missing, or chipped teeth on the crankshaft reluctor wheel will cause signal dropouts that trigger P0335.
Wiring and connector issues A continuity test on the harness wires between the sensor and the ECM can reveal breaks, chafing, or high-resistance connections.
ECM connector corrosion Moisture in the ECM connector on GM trucks (especially 1999–2007 Silverado and Sierra) is a known issue that mimics sensor failure.
Intermittent failure The sensor's internal windings can break down under heat. A resistance test at room temperature may pass, but the sensor fails when the engine reaches operating temperature. If you suspect this, warm the sensor with a heat gun and retest.

What are the most common mistakes people make during this test?

Testing the wrong side of the connector. You need to measure resistance at the sensor itself not the harness side that feeds back to the ECM. Measuring the harness side can include ECM internal resistance and give false readings.
Ignoring temperature. Resistance changes with temperature. The spec assumes room temperature. If you just drove the vehicle, let the sensor cool down for 15–20 minutes before testing.
Using the wrong multimeter range. If your meter auto-ranges, make sure it settled on a stable reading. If you manually set the range too high (like 200kΩ), small differences become hard to see. Use the 2kΩ range for CKP sensors.
Forgetting to inspect the connector. Corroded, spread, or backed-out pins on GM weather-pack connectors are a frequent cause of P0335 that has nothing to do with the sensor itself.
Replacing the sensor without checking the reluctor ring. A new sensor mounted in front of a damaged reluctor wheel will set the same code immediately.

Does resistance testing work on the 24x and 58x reluctor GM systems?

Yes, resistance testing applies to the sensor itself regardless of whether your GM engine uses a 24-tooth or 58-tooth reluctor wheel. The sensor winding resistance spec stays in the 500–900 ohm range for most VR-type GM sensors used across both systems. However, the signal waveform and voltage output differ between these systems, which matters if you move on to oscilloscope testing. The resistance test is your starting point it tells you if the sensor coil is intact.

What should you do after the resistance measurement?

Here is a practical checklist to follow after you finish the resistance test:

Record your resistance reading and compare it to the factory spec for your exact vehicle.
If resistance is out of range, replace the CKP sensor with a quality OEM or OE-equivalent part (ACDelco is the OEM supplier for most GM applications).
If resistance is within range, check the wiring harness for continuity and short-to-ground between the sensor connector and the ECM.
Inspect the connector pins for corrosion, spreading, or moisture intrusion clean with electrical contact cleaner and apply dielectric grease on reassembly.
Visually check the reluctor ring if accessible. Look for damaged or missing teeth.
Clear the P0335 code with an OBD-II scanner and road test the vehicle. Monitor for code return.
If the code returns with a known-good sensor and intact wiring, consider oscilloscope testing to evaluate the signal waveform or have the ECM tested at a qualified shop.

Resistance measurement is the fastest way to confirm or rule out a bad crankshaft position sensor on your GM or Chevrolet. It takes five minutes, costs nothing if you already own a multimeter, and saves you from the parts-cannon approach that wastes time and money.