P0337

DTC P0337

Circuit Description

The crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. The CKP sensor produces an AC voltage of different amplitude and frequency. The frequency depends on the velocity of the crankshaft, and the AC voltage output depends on the crankshaft position and battery voltage. The CKP sensor works in conjunction with a 58X reluctor wheel attached to the crankshaft. The engine control module (ECM) can synchronize the ignition timing, fuel injector timing, and spark knock control based on the CKP and the camshaft position (CMP) sensor inputs. The CKP sensor is also used to detect misfire and tachometer display. The shielded ground circuit is connected to ground. The circuits between the CKP sensor and the ECM consists of the following circuits:

* A signal

* A low reference

* A shielded ground

If the ECM detects no pulses from the CKP sensor, DTC P0337 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0337 Crankshaft Position (CKP) Sensor Circuit Low Duty Cycle

Conditions for Running the DTC

* The ECM monitors the CKP sensor while the engine is cranking. The ECM uses the CMP sensor to determine if the engine is cranking. If DTC P0341 or P0342 is set, the ECM then monitors the manifold absolute pressure (MAP) sensor signal to determine if the engine is cranking.

* The engine is cranking.

* DTC P0337 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects no CKP pulses during engine cranking for 8 seconds.

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.