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How to Replace the Crank Sensor on a 2001 Chevrolet S-10

by Richard Rowe

Just as in the aftermath of the Great Depression, the aftermath of the 2009 recession has seen one of the largest booms in luxury car sales of all time. This is a nice indicator of a nation's welfare, if you happen to think that the speed of the jet stream at 80,000 feet has anything to do with the barometer reading at ground level. The rest of us, though, are keeping our cars longer than ever, and working-man's heroes like the S-10 have taken on a truly special place in our nation's collective heart.

Step 1

Lift the front of the truck with a floor jack, and support it on jack stands.

Step 2

Locate your crankshaft position sensor. On the 4.3-liter engine, the crank sensor is readily accessible from the bottom, bolted to the bottom of the timing cover under and behind the crankshaft pulley. On the 2.2-liter engine, it's over the starter, between the top of the starter and the bottom of the manifold.

Step 3

On the 4.3-liter engine, simply remove the one bolt securing the crank sensor to the bottom of the timing cover, and pull the sensor out. Unplug the sensor and inspect the flat, metal portion on the bottom of the sensor. If you see a semi-circular divot cut out of the middle, refer to the Tips section below. Otherwise, plug a new sensor into the hole, snug the bolt down hand tight, and plug the sensor in.

Step 4

On the 2.2-liter engine, reach over the starter and feel for the sensor; you can find it by tracing the wiring to the sensor. Once you locate the bolt on the side, remove the bolt, and pull the sensor out of the hole. Unplug it from the wiring harness. Push a new sensor into the hole, thread the bolt in and snug it down hand tight. Plug the wiring harness in. Refer to the Tips section below if you prefer not to do this operation "blind," or have trouble locating the sensor.

Lower the truck. Start the engine and watch the check-engine light. If it doesn't turn off when the truck starts, drive down to your local auto parts store and ask to use the OBD-II scanner to clear the stored trouble codes.


  • The 4.3-liter, like the small-block from which it's derived, is notorious for a simple kind of crank position sensor failure. The sensor, bolted to the plastic timing cover, has a tendency to move inward and grind against the harmonic balancer -- hence the small divot on the face of the sensor. The problem here is that even if you install a new sensor, the new one may well grind against the balancer, so the truck will still malfunction.
  • Before you replace the sensor, you might try buying a sensor shim from GM or your local auto parts store; most carry them. The shim will move the old sensor away from the balancer, restoring the tiny clearance that it needs to work. If your auto parts store doesn't carry them, you can make a shim by cutting a ring out of gasket paper, and sliding it around the round sensor body before bolting it back in. The gasket-paper ring is at least a good short-term solution until you can get to a GM dealership to order the proper shim ring.
  • The 2.2-liter Engine: The crank sensor is very easy to access if you drop the starter, which is very easy. Place your floor jack under the starter between the bolt holes to hold it. Remove the two starter bolts, and lower the starter enough to see the sensor over it. There's enough slack in the electrical wiring that you can just swing it down a bit and out of the way. When you're finished, lift the starter up and use a torque wrench to tighten the starter bolts to 32 foot-pounds. Do not touch the starter or attempt to replace the crank sensor on this engine without disconnecting the battery -- you'll almost certainly electrocute yourself when you accidentally bump the hot starter cable with the end of your ratchet.

Items you will need

  • Memory saver
  • Ratchet
  • Socket set
  • Floor jack
  • Jack stands
  • Torque wrench

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