The crankshaft position (CKP) system variation compensating
values are stored in the powertrain control module (PCM) non-volatile memory
after a learn procedure has been performed. If the actual crankshaft position
system 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
.
If any of the following conditions are true, perform the CKP System
Variation Learn Procedure :
| • | The PCM has been replaced. |
| • | The engine has been replaced. |
| • | The crankshaft has been replaced. |
| • | The crankshaft harmonic balancer has been replaced. |
| • | The CKP sensor has been replaced. |
Important: The scan tool crankshaft position system variation learn function will
be inhibited if the engine coolant temperature (ECT) is less than 70°C
(158°F). Allow the engine to warm to at least 70°C (158°F)
before attempting the CKP System Variation Learn Procedure.
If any diagnostic trouble codes (DTCs), other than DTC P1336,
are set before or during the CKP learn procedure, the scan tool CKP learn
function will be inhibited. Diagnose and repair any DTCs set. Refer to
the applicable DTCs.
The CKP system variation learn function will be inhibited if the following
conditions are true:
| • | The PCM detects a malfunction involving the camshaft position
signal circuit. |
| • | The 3 X reference circuit |
| • | The 24 X reference circuit |
If a malfunction has been indicated, refer to the following list
to diagnose the system or the sensor:
The scan tool CKP system variation learn function will not be enabled
until the engine coolant temperature reaches 70°C (158°F).
Selecting the CKP System Variation Learn Procedure on the scan tool
will command the PCM to enable CKP system variation learn fuel cutoff
and allow the crankshaft position system variation compensating values
to be stored in the PCM. The PCM must detect an engine speed of 5,150 RPM
during the CKP System Variation Learn Procedure. This procedure occurs
in order to store the crankshaft position system variation compensating
values and in order to complete the procedure.
Important: Block the drive wheels when performing the CKP System Variation Learn
Procedure in order to prevent personal injury. Set the vehicle parking
brake when instructed by the scan tool. Quickly increase the accelerator
pedal position until reaching wide open throttle and hold. During the learn
procedure, the PCM will automatically control the injector operation. When
the RPM has reached a certain RPM, the PCM will stop the fuel injectors
from pulsing, until the learn procedure is finished. When the PCM has learned
the crankshaft variation, the fuel injectors will return to normal operation
and the engine will begin to accelerate again. Release the throttle when
the engine reaches the second fuel cut-off. Leaving the throttle open
during the fuel cut-off learn procedure will allow the engine to decelerate
at an even rate.
- Block the drive wheels.
- Ensure the hood is closed.
- Start the engine and allow the engine coolant temperature (ECT)
to reach at least 70°C (158°F).
- Turn OFF the ignition.
- Select and enable the CKP System Variation Learn Procedure with
the scan tool.
- Set the parking brake when instructed by the scan tool.
- Start the vehicle.
- Apply and hold the service brake pedal firmly.
- Ensure the transaxle is in Park.
- Steadily increase the accelerator pedal until the fuel cutoff
is reached at 5,150 RPM and hold. Release the accelerator pedal after
the second fuel cutoff has been reached.
- The crankshaft position system variation compensating values
are learned when the RPM decreases back to idle.
- Observe the DTC status for DTC P1336.
- If the scan tool indicates that DTC P1336 ran and passed,
the CKP System Variation Learn Procedure is complete. If the scan tool indicates
DTC P1336 failed or not run, determine if other DTCs have set.
If DTCs other than DTC P1336 are not set, repeat the CKP System Variation
Learn Procedure as necessary.
