Crankshaft position sensor location for replacement please?

Hello,

There are two crankshaft position sensors on this car one at the front of the crankshaft and the other on the side of the block which will need to have a relearn which I have included as well.

this guide will walk you through the steps with the instructions on how to change the sensor for your car below.

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

Removal (3.8L)

1. Turn OFF the ignition. Disconnect the negative battery cable. Remove the drive belt. Raise and support the vehicle. Remove the right front tire and wheel. Remove the right engine splash shield retainers and the engine splash shield. Remove the torque converter cover. Install the Flywheel Holder (J-37096) to hold the flywheel.

CAUTION: Do not separate the crankshaft pulley from the crankshaft balancer. Service the crankshaft pulley and the crankshaft balancer as an assembly.
2. Remove the crankshaft balancer retaining bolt. Install the Crankshaft Balancer Remover (J-38197-A). Remove the crankshaft balancer. Remove the crankshaft balancer remover. Disconnect the Crankshaft Position (CKP) sensor electrical connector. Remove the CKP sensor shield. See Fig 3. DO NOT use a pry bar. Remove the CKP sensor studs. Remove the CKP sensor.

Fig 3: Removing Crankshaft Position Sensor Shield (3.8L)

Installation

1. Install the CKP sensor. Install the CKP sensor studs. Tighten the studs to specification. See TORQUE SPECIFICATIONS. Install the CKP sensor shield. Connect the CKP sensor electrical connector.
2. Coat the engine front cover seal contact area on the crankshaft balancer, and the seal surface with clean engine oil. Install the crankshaft balancer. Install the crankshaft balancer retaining bolt. Use the Flywheel Holder (J-37096) to keep the flywheel from turning. Tighten the crankshaft balancer bolt to specification.
3. Remove the flywheel holder. Install the torque converter cover. Install the right engine splash shield and the engine splash shield retainers. Install the right front tire and wheel. Lower the vehicle. Install the drive belt. Reconnect the negative battery cable. Perform the CKP System Variation Learn Procedure. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.

See if you can rent/borrow them from an auto-parts store or purchase used ones on eBay, etc, then when done turn around and sell them right back at a slightly lower price.

Just so you know, if you decide to have a shop do it, it calls for about 1.5 hours to remove and replace which includes the relearn.

This is that crank sensor replacement instructions,
CRANKSHAFT POSITION SENSOR
Removal (3.1L & 3.4L - CKP Sensor "A")
Crankshaft Position (CKP) sensor "A" may also be referred to as CKP sensor 24X. CKP sensor is located behind the crankshaft balancer. See Fig 1. Turn OFF the ignition. Remove the drive belt. Raise and support the vehicle. Remove the lower air deflector. Disconnect the CKP sensor harness connector.
Remove the crankshaft balancer bolt. Using Crankshaft Balancer Puller (J-24420-C), remove the crankshaft balancer. Note the routing of the CKP sensor harness before removal. Remove the harness retaining clip and bolt. Disconnect the CKP sensor electrical connector. Remove the sensor bolts. Remove the CKP sensor.
Installation
Install the CKP sensor with bolts and the route harness as noted during removal. Install the harness retaining clip and bolt. Tighten the bolts to specification. See TORQUE SPECIFICATIONS.
Connect the CKP sensor electrical connector. Apply Sealer (12345739) or the equivalent to the keyway of the crankshaft balancer. Install the crankshaft balancer into position over the key in the crankshaft. Using Crankshaft Balancer Installer (J-29113), install the crankshaft balancer to the crankshaft.
Remove the crankshaft balancer installer from the crankshaft balancer. Install the crankshaft balancer washer and the crankshaft balancer bolt. Tighten the bolt to specification.
Install the lower air deflector. Lower the vehicle. Install the drive belt. Perform the CKP System Variation Learn Procedure. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.
Fig 1: Locating Crankshaft Position Sensor "A" (3.1L & 3.4L)
G00028468
Courtesy of GENERAL MOTORS CORP.
Removal (3.1L - CKP Sensor "B")
The Crankshaft Position (CKP) sensor "B" may also be referred to as CKP sensor 7X. CKP sensor is mounted in cylinder block. See Fig 2. Turn the steering wheel fully to the left. Raise and support the vehicle. Remove the right front tire and wheel.
Disconnect the CKP sensor electrical connector. Remove the CKP sensor attaching bolt. Remove the CKP sensor from the engine. Inspect for wear, cracks, or leakage if the sensor is not being replaced.
Installation
Replace the "O" ring, if it is damaged. Lubricate the "O" ring with clean engine. Install the sensor to the block. Install the CKP sensor attaching bolt. Tighten the bolt to specification. See TORQUE SPECIFICATIONS.
Install the CKP sensor electrical connector. Install right front tire and wheel. Lower the vehicle. Perform the CKP System Variation Learn Procedure. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.
Fig 2: Locating Crankshaft Position Sensor "B" (3.1L & 3.8L)
G00028469
Courtesy of GENERAL MOTORS CORP.
Removal (3.8L)
Turn OFF the ignition. Disconnect the negative battery cable. Remove the drive belt. Raise and support the vehicle. Remove the right front tire and wheel. Remove the right engine splash shield retainers and the engine splash shield. Remove the torque converter cover. Install the Flywheel Holder (J-37096) to hold the flywheel.
CAUTION: Do not separate the crankshaft pulley from the crankshaft balancer. Service the crankshaft pulley and the crankshaft balancer as an assembly.
Remove the crankshaft balancer retaining bolt. Install the Crankshaft Balancer Remover (J-38197-A). Remove the crankshaft balancer. Remove the crankshaft balancer remover. Disconnect the Crankshaft Position (CKP) sensor electrical connector. Remove the CKP sensor shield. See Fig 3. DO NOT use a pry bar. Remove the CKP sensor studs. Remove the CKP sensor.
Fig 3: Removing Crankshaft Position Sensor Shield (3.8L)
G94J32101
Courtesy of GENERAL MOTORS CORP.
Installation
Install the CKP sensor. Install the CKP sensor studs. Tighten the studs to specification. See TORQUE SPECIFICATIONS. Install the CKP sensor shield. Connect the CKP sensor electrical connector.
Coat the engine front cover seal contact area on the crankshaft balancer, and the seal surface with clean engine oil. Install the crankshaft balancer. Install the crankshaft balancer retaining bolt. Use the Flywheel Holder (J-37096) to keep the flywheel from turning. Tighten the crankshaft balancer bolt to specification.
Remove the flywheel holder. Install the torque converter cover. Install the right engine splash shield and the engine splash shield retainers. Install the right front tire and wheel. Lower the vehicle. Install the drive belt. Reconnect the negative battery cable. Perform the CKP System Variation Learn Procedure. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.

You will need a scan tool but here is the procedure.
As you can see the engine is running, so no this procedure if not done will not prevent the engine from running. I think you still have a security issue.
CAUTION: Before performing crankshaft position system variation learn procedure, always set parking brake and block drive wheels in order to prevent personal injury. Release throttle immediately when engine starts to decelerate in order to eliminate over-revving engine. Once learn procedure has been completed, control module will return engine control to operator and engine will respond to throttle position.
NOTE: Battery must be fully charged and in good condition. Scan tool connection at Data Link Connector (DLC) should be clean and tight before starting crankshaft position system variation learn procedure.
Install scan tool. Close hood.
With a scan tool, monitor the powertrain control module for DTCs. If other DTCs are set, except DTC P1336, diagnose affected DTC(s). See appropriate SELF-DIAGNOSTICS article.
With a scan tool, select the Crankshaft Position (CKP) variation learn procedure.
Observe the fuel cut-off for the engine that you are performing the learn procedure on.
The scan tool instructs you to perform the following:
Block drive wheels.
Apply parking brakes.
Cycle ignition from OFF to ON.
Apply and hold brake pedal.
Start and idle engine.
Turn OFF A/C.
Place transmission in Park (A/T) or Neutral (M/T).
The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components:
CKP sensor activity. If there is a CKP sensor condition, refer to the applicable DTC that set. See appropriate SELF-DIAGNOSTICS article.
CMP sensor activity. If there is a CMP sensor condition, refer to the applicable DTC that set. See appropriate SELF-DIAGNOSTICS article.
If ECT is not warm enough, idle engine until engine coolant temperature reaches correct temperature.
With the scan tool, enable the CKP system variation learn procedure.
NOTE: While learn procedure is in progress, release throttle immediately when engine starts to decelerate. The engine control is returned to operator and engine responds to throttle position after the learn procedure is complete.
Slowly increase the engine speed to the RPM that you observed.
Immediately release the throttle when fuel cut-off is reached.
The scan tool displays Learn Status: Learned this ignition. If scan tool does NOT display this message and no additional DTCs set, diagnose for an engine mechanical problem. If a DTC set, diagnose affected DTC(s). See appropriate SELF-DIAGNOSTICS article.
Turn ignition off for 30 seconds after the learn procedure is completed successfully.