How to Change the Crankshaft Sensor on a 1999 S-10 Blazer V6

In 1982, Chevrolet released its new compact pickup, the S-10. The following year, Chevy saw an opportunity in the midsize SUV market and released the S-10 Blazer, which was based on the S-10 platform. In 1988, Chevy bumped the Blazers base output up a drastic 68 horsepower when it dropped the base 2.5-liter in favor of a standard 4.3-liter V-6. Replacing the crankshaft position sensor on the 1999 Blazer is a fairly simple task, but you must perform a relearn procedure after installing a new sensor.

Instructions

Crankshaft Position Sensor Replacement

1

Lift the front of the Blazer with a floor jack and slide jack stands under the SUVs frame rails. Lower the vehicle onto the jack stands.

2

Crawl under the vehicle and remove the bolts securing the under-engine skidpan, if equipped, with a ratchet and socket, and remove the skidpan.

3

Find the crankshaft position sensor bolted to the engine block, just under the crankshaft pulley. Pry upward on the locking tab on the crankshaft position sensors wiring harness with a flat-head screwdriver and unplug the wiring harness from the sensor.

4

Remove the bolt securing the crankshaft position sensor, using a ratchet and socket, and pull the sensor from the engine block with a slight wiggling motion.

5

Apply a thin coat of new engine oil to the new crankshaft position sensors O-ring and press the sensor into its hole in the engine block. Hand-tighten the crankshaft position sensors retaining bolt, then torque it to 15 foot-pounds with a torque wrench and socket.

6

Plug the wiring harness into the receptacle on the new crankshaft position sensor.

7

Lift the under-engine skidpan into place and hand-thread its retaining bolts, if equipped. Tighten the skidpan bolts to 24 foot-pounds with a torque wrench and socket.

8

Raise the Blazer from the jack stands with a floor jack and remove the jack stands. Lower the vehicle to the ground.

Crankshaft Position Sensor Relearn Procedure

9

Position wheel chocks around the front and rear wheels and set the parking brake.

10

Find the data link connector the male plug in the same shape as your OBD-II scanners female plug under the drivers side of the dashboard. Plug the scanner into the DLC.

11

Start the engine and turn on the OBD-II scanner. Most scanners turn on automatically when you turn the vehicle on. If your scanner did not turn on, follow the scanners instruction to turn it on. When prompted, enter you Blazers information vehicle identification number, year, make, model, etc. by following the instructions given by the scanner.

12

Place the transmission in Park if your truck has an automatic transmission or Neutral if it has a manual transmission. Allow the engine to idle until it reaches operating temperature, roughly halfway up the temperature gauge.

13

Switch off any accessories on the vehicle, including: windshield wipers, radio, turn signals and headlights.

14

Begin the Crankshaft Position Sensor Variation Relearn Procedure in the OBD-II scanner. This process varies greatly, depending on the style of scanner you use, so refer to the scanners instruction manual and on-screen prompts to begin the procedure.

15

Press and hold the brake pedal to activate the relearn procedure. Keep the brake pedal depressed throughout the entire relearn process.

16

Slowly press the accelerator pedal until the engine speed reaches 4,000 rpm. Release the accelerator pedal as soon as you hear the engine speed start decreasing automatically.

17

Wait for the scanner to prompt you that the relearn procedure was a success. Turn the ignition to the Off position for about 15 seconds to complete the task.

18

Remove the wheel chocks.