GM Service Manual Online
For 1990-2009 cars only

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 provide an overview of each diagnostic category.

DTC Descriptor

DTC P01320: Crankshaft Position (CKP) System Variation Not Learned

Circuit/System Description

The crankshaft position (CKP) system variation learn feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the crankshaft position sensor. The calculated error allows the engine control module (ECM) to accurately compensate for reference period variations. This enhances the ability of the ECM to detect misfire events over a wider range of engine speed and load.

The CKP system variation compensating values are stored in ECM memory after a learn procedure has been performed. If the actual CKP variation is not within the CKP system variation compensating values stored in the ECM, DTC P0300 may set.

Conditions for Running the DTC

    • The engine is operating.
    • The DTC runs continuously when the above condition is met.

Conditions for Setting the DTC

The ECM detects an incorrect CKP system variation values during deceleration or fuel cut-off.

Action Taken When the DTC Sets

DTC P1320 is a Type B DTC.

Conditions for Clearing the DTC

DTC P1320 is a Type B DTC.

Reference Information

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions
    •  Scan Tool Output Controls

Circuit/System Testing

    Important: The engine control module (ECM) continuously learns the crankshaft position (CKP) system variations. A CKP variation learn procedure cannot be performed with a scan tool.

  1. If the scan tool displays NOT learned this ignition, inspect for the following conditions:
  2. • A worn or damaged crankshaft or crankshaft bearings.
    • Debris between the CKP sensor and the reluctor wheel
    • A damaged reluctor wheel.
    • Excessive crankshaft runout.
    • Any interference of the CKP Sensor or CKP Sensor signal to the control module.
  3. If the control module is unable to complete the learn procedure, replace the control module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming