Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P1321: Crankshaft Position (CKP) Reluctor Wheel PerformanceDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
CKP Sensor Signal | P0335, P0337 | P0335, P0337 | P0335, P0337 | P0336, P1321 |
Low Reference | -- | P0335, P0337 | -- | P0336, P1321 |
Shielded Ground | -- | -- | -- | P0336, P1321 |
Circuit/System Description
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 signal |
| • | The low reference |
| • | The shielded ground |
Conditions for Running the DTC
| • | The engine is running. |
| • | The number of extra or missing teeth is more than or equal to 2 per revolution. |
| • | The DTC runs continuously when the above conditions are met. |
Conditions For Setting the DTC
The ECM detects more or less than 58 reference pulses for 10 crankshaft revolutions.
Action Taken When the DTC Sets
DTC P1321 is a Type B DTC.
Conditions for Clearing the DTC
DTC P1321 is a Type B DTC.
Diagnostic Aids
The following conditions could also set the DTCs:
| • | Physical damage to the CKP sensor or the reluctor wheel |
| • | Excessive play or looseness of the CKP sensor or the reluctor wheel |
| • | Improper installation of the CKP sensor or the reluctor wheel |
| • | Foreign material passing between the CKP sensor and the reluctor wheel |
| • | Excessive air gap between the CKP sensor and the reluctor wheel |
Reference Information
Schematic Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine running, observe the DTC information with a scan tool. DTC P1321 should not set.
- Move related harnesses/connectors of the CKP sensor and verify the engine does not stumble, stall, or change engine speed.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the crankshaft position (CKP) sensor.
- Ignition ON, test for 1.5-2.0 volts between the signal circuit terminal 2 and the low reference circuit terminal 1.
- If all circuits test normal, test or replace the CKP sensor.
Important: If the CKP sensor lead is damaged in any way, replace the CKP sensor.
| ⇒ | If less than the specified range, test the applicable circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the applicable circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming |
