GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 LaCrosse 🢒 DTC 🢒 DTC P0315

Circuit 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 powertrain control module (PCM) to accurately compensate for reference period variations. This enhances the ability of the PCM to detect misfire events over a wider range of engine speed and load.

The CKP system variation compensating values are stored in PCM memory after a learn procedure has been preformed. If the actual CKP variation is not within the CKP system variation compensating valves stored in the PCM, DTC P0300 may set. If the CKP system variation values are not stored in the PCM memory, DTC P0315 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0315 Crankshaft Position (CKP) System Variation Not Learned

Conditions for Running the DTC

This diagnostic runs continuously.

Conditions for Setting the DTC

The CKP system variation values are not stored in the PCM memory for more than 0.5 second.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Important: The crankshaft position (CKP) variation learn procedure may need to be repeated up to 5 times before the powertrain control module (PCM) learns the variation.

Perform the CKP system variation learn procedure. Refer to Crankshaft Position System Variation Learn .

Does the scan tool display Learned This Ignition?

Go to Step 4

Go to Step 3

3

Inspect for the following conditions:

    • Worn crankshaft bearings
    • A damaged or misaligned reluctor wheel
    • Debris between the CKP sensor and the reluctor wheel
    • Excessive crankshaft runout
    • A damaged crankshaft--Refer to Crankshaft and Bearing Cleaning and Inspection.
    • Electromagnetic Interference in the signal circuit of the CKP sensor
    • The ignition switch is in the ON position until the battery has insufficient system voltage.
    • A PCM power disconnect with the ignition ON may erase the stored value and set DTC P0315.

Did you complete the inspection?

Go to Step 4

--

4
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 5

5

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK