GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 Epica 🢒 Engine 🢒 Engine Controls - 2.5L (LBK) 🢒 DTC P1320

Circuit Description

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.

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 reluctor wheel. 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 ECM continuously learns the CKP system variation values. If the actual CKP variation is not within the CKP system variation compensating valves stored in the ECM, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1320 Crankshaft Position (CKP) System Variation Not Learned

Conditions for Running the DTC
    • The engine speed is between 1,600-5,500 RPM
    • DTC P1320 runs continuously once the above conditions are met.

Conditions for Setting the DTC
    • The ECM detects an incorrect CKP system variation values.
    • The above condition is detected on decelerations or when a fuel cut-off occurs.

Action Taken When the DTC Sets
    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the MIL/DTC
    • 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 non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Attempt to start the engine
  2. Observe the DTC Info. with a scan tool.

Did DTC P1320 fail this ignition?

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  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 4

Go to Intermittent Conditions

4
  1. Attempt to start the engine
  2. Observe the DTC Info with a scan tool.

Is DTC P0335, P0336, P0337, or P1321 also set?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 5

5

Important: If the reluctor wheel is damaged, replace the CKP sensor and the crankshaft. Refer to Crankshaft Position Sensor Replacement .

Turn OFF the ignition.

Inspect the reluctor wheel, crankshaft, and the CKP sensor for the following conditions:

    • Physical damage
    • Improper installation
    • Excessive end play or looseness
    • Debris between the CKP sensor and the reluctor wheel

Refer to Crankshaft Replacement in Engine Mechanical - 2.5L (LBK).

Did you complete the inspection?

Go to Step 6

--

6
  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 7

7

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK