For 1990-2009 cars

Refer to Engine Controls Schematics .

### Circuit Description

The Crankshaft Position System Variation Learning feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, the crankshaft balancer interrupter rings, and the crankshaft position sensor hall effect switches. The calculated error allows the PCM to accurately compensate for reference period variations. The Crankshaft Position System Variation Learning feature enhances the ability of the PCM to detect misfire events over a wider range of engine speed and load.

The crankshaft position system variation values are stored in the PCM non volatile memory after the Crankshaft Position System Variation Learn procedure has been performed. DTC P1336 set indicates that the crankshaft position system variation values have not been stored in the PCM and the Crankshaft Position System Variation Learn procedure must be performed. The learn procedure is required after the following service procedures have been performed, regardless of whether or not DTC P1336 is set:

• | An PCM replacement

• | An engine replacement

• | A crankshaft replacement

• | A crankshaft balancer replacement

• | A crankshaft position sensor replacement

• | Any engine repairs which disturbs crankshaft/harmonic balancer to crankshaft position sensor relationship

### Conditions for Running the DTC

• | CMP or CKP sensor DTCs are not set.

• | ECT is more than 65°C (149°F).

### Conditions for Setting the DTC

Crankshaft position system variation values are not stored in the PCM memory.

### Action Taken When the DTC Sets

• | The PCM will illuminate the malfunction indicator lamp (MIL) during the first trip in which the diagnostic test has been run and failed.

• | The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed.

• | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• | The DTC can be cleared by using a scan tool.

### Diagnostic Aids

The crankshaft position system variation compensating values are stored in the PCM non volatile memory after a learn procedure has been performed. If the actual crankshaft position variation is not within the crankshaft position system variation compensating values stored in the PCM, DTC P0300 may set. Refer to Diagnostic Aids for DTC P0300.

The Crankshaft Position System Variation Learn procedure must be performed when replacing the PCM to clear DTC P1336. The Crankshaft Position System Variation Learn procedure is also required when the following service procedures have been performed, regardless of whether or not DTC P1336 is set:

• | An engine replacement

• | A crankshaft replacement

• | A crankshaft balancer replacement.

• | A crankshaft position sensor replacement

• | Any engine repairs which disturbs crankshaft/harmonic balancer to crankshaft position sensor relationship

If the crankshaft position system variation learn procedure cannot be performed successfully, inspect for the following conditions and correct as necessary:

• | ECT below 70°C (158°F)--Allow the engine to warm to above 70°C (158°F).

• | Powertrain DTCs set--Refer to Powertrain On Board Diagnostic (OBD) System Check .

| The scan tool crankshaft position system variation learn function will be disabled if any Powertrain DTCs other than DTC P1336 are stored

• | Camshaft position signal problem detected--Refer to DTC P0341 Camshaft Position (CMP) Sensor Performance .

• | 3X reference signal problem detected--Refer to DTC P1374 Crankshaft Position (CKP) High to Low Resolution Frequency Correlation .

• | 24X reference signal problem detected--Refer to DTC P0336 Crankshaft Position (CKP) Sensor Performance .

Many situations may lead to an intermittent condition. Perform each inspection or test as directed.

Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

• | Loose terminal connection

- | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.

- | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.

• | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.

• | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.

If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.

#### DTC P1336 - Crankshaft Position System Variation Not Learned

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you preform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | Perform the crankshaft position system variation learn procedure. Refer to Crankshaft Position System Variation Learn . Did you complete the repair? | -- | System OK | --