The crankshaft position (CKP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit, and an output signal circuit. The CKP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The CKP sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the CKP sensor output depends on the velocity of the crankshaft. The CKP sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the CKP sensor. The ECM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The ECM also uses CKP sensor output information to determine the camshaft relative position to the crankshaft, to detect cylinder misfire, and to control the camshaft position (CMP) actuator if equipped.

P0335

The ECM does not detect a signal from the CKP sensor. OR, the ECM detects a CKP signal with out reference pulse for more than 6 revolutions. Either condition exists for greater than 1 second.

P0336

The ECM re-syncs the engine position 2,600 or more times during an ignition cycle. OR, the ECM detects 28 or more interruptions in the engine speed signal during an ignition cycle. Either condition exists for greater than 1 second.

P0338

The ECM detects a difference of more than 250 teeth between reference gap position pulses for 4 consecutive crankshaft revolutions in which the same number of pulses are detected each crankshaft revolution or a cumulative of 50 seconds.

DTCs P0335, P0336, and P0338 are Type B DTCs.

DTCs P0335, P0336, and P0338 are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, inspect the engine wiring harness carrying the CKP sensor circuits for the following conditions:

•	Close routing of aftermarket electrical equipment

•	Close to solenoids, motors, and relays

⇒	Correct any wire harness routing or component placement conditions if it is determined to be a possible source of electrical interference.

2. Ignition ON, engine OFF, use the live plot function on the scan tool. Select the engine speed parameter and the CKP sensor parameter. Change the minimum spec to 400 RPM for both parameters. Change the maximum spec to 4,000 RPM for both parameters.
3. Start the engine and observe the scan tool.
4. Quickly accelerate and release the accelerator pedal several times. Do not accelerate past 4,000 RPM. The two graphed lines on the live plot display should track together across the screen.

1. Ignition OFF, disconnect the harness connector at the B26 CKP sensor.
2. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.

3. Ignition ON, engine OFF, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 1 and ground.

⇒	If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

⇒	If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.

4. Ignition ON, engine OFF, test for 4.8-5.2 volts between the signal circuit terminal 3 and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.

5. Ignition OFF, connect a fused jumper wire to signal circuit terminal 3.
6. Ignition ON, momentarily touch the other end of the fused jumper wire to the battery negative post repeatedly. The CKP Active Counter and the CMP sensor parameter should change.

⇒	If the CKP Active Counter and the CMP sensor parameter change, test or replace the B26 CKP sensor.

⇒	If the CKP Active Counter and the CMP sensor parameter does not change, replace the K20 ECM.

7. Ignition OFF, inspect the B26 CKP sensor for correct installation.

⇒	If the sensor is loose, inspect the sensor and the O-ring for damage. Replace as necessary.

8. Inspect the engine for the following conditions:

•	Engine oil for debris

•	Crankshaft reluctor wheel for damage

•	Timing chain, tensioner, and sprockets for wear or damage

⇒	If debris is found in the engine oil, inspect the internal engine components to determine the cause. Repair or replace any worn or damaged components. Refer to Camshaft Timing Chain and Sprocket Cleaning and Inspection and Camshaft Cleaning and Inspection.

9. If all circuits and components test normal, test or replace the B26 CKP sensor.

Note: You must perform the Circuit/System Testing before proceeding with Component Testing.

1. Remove the B26 CKP sensor and inspect the sensor and the O-ring for damage.

⇒	If the sensor is loose, incorrectly installed, or damaged, replace the B26 CKP sensor.

2. Connect the connector to the B26 CKP sensor.
3. Ignition ON, engine OFF, observe the CKP Active Counter while passing a steel object by the tip of the sensor repeatedly. The CKP Active Counter should increment.

⇒	If the CKP Active Counter does not increment, replace the B26 CKP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.