For 1990-2009 cars

### 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 P0315: 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.

If the CKP system variation values are not stored in the ECM memory, DTC P0315 sets.

### Conditions for Running the DTC

• | DTCs P0016, P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0132, P0201, P0202, P0203, P0204, P0324, P0325, P0335, P0336, P0340, P0351, P0352, P0402, P0404, P0405, P0406, P042E, P0502, and P0700 are not set.

• | The engine coolant temperature (ECT) is more than 65°C (149°F).

• | DTC P0315 runs continuously once the above conditions are met.

### Conditions for Setting the DTC

The ECM detects that the CKP system variation values are not stored in memory.

### Action Taken When the DTC Sets

DTC P0315 is a Type B DTC.

### Conditions for Clearing the DTC

DTC P0315 is a Type B DTC.

### Reference Information

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Testing

Important: The CKP System Variation Learn Procedure may have to be repeated up to 5 times before the procedure is learned.

Perform the Crankshaft Position System Variation Learn .

1. If the scan tool displays NOT learned this ignition, inspect for the following conditions:

• | 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.

2. 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