The crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. The CKP sensor produces an AC voltage of different amplitude and frequency. The frequency depends on the velocity of the crankshaft, and the AC voltage output depends on the crankshaft position and battery voltage. The CKP sensor works in conjunction with a 58X reluctor wheel attached to the crankshaft. The engine control module (ECM) can synchronize the ignition timing, fuel injector timing, and spark knock control based on the CKP and the camshaft position (CMP) sensor inputs. The CKP sensor is also used to detect misfire and tachometer display. The CKP sensor circuits are connected directly to the ECM. The circuits between the CKP sensor and the ECM consist of the following circuits:

The ECM detects more or less than 58 reference pulses for 10 crankshaft revolutions.

DTC P1321 is a Type B DTC.

DTC P1321 is a Type B DTC.

The following conditions could also set the DTCs:

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. Start the engine, observe the DTC information with a scan tool. DTC P1321 should not set.
2. Move related harnesses/connectors of the CKP sensor and verify the engine does not stumble, stall, or change engine speed.
3. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

Important: If the CKP sensor lead is damaged in any way, replace the CKP sensor.

1. Ignition OFF, disconnect the harness connector of the CKP sensor.
2. Ignition ON, verify that 1.5-2.0 volts is available on the signal circuit and the low reference circuit of the CKP sensor.

⇒	If less than 1.5 volts, test the applicable circuit for a short to ground or an open/high resistance. If the circuits/connections test normal, replace the ECM.

⇒	If more than 2.0 volts, test the applicable circuit for a short to voltage. If the circuits/connections test normal, replace the ECM.

3. If all circuits/connections test normal, test or replace the CKP sensor.

1. Ignition OFF, disconnect the harness connector of the CKP sensor.

Important: If the CKP sensor lead is damaged in any way, replace the CKP sensor.

2. Connect a DMM between the signal circuit and the low reference circuit of the CKP sensor.
3. Test for 460-620 ohms between the signal circuit and low reference circuit.

⇒	If the resistance is not within the specified range, replace the CKP sensor.

4. Disconnect the fuel pump relay.
5. Set the DMM to the AC voltage scale.
6. While cranking the engine, test for more than 1.4 ACV between the signal circuit and low reference circuit of the CKP sensor.

⇒	If less than 1.4 ACV, replace the CKP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.