DTC P0336 Crankshaft Position (CKP) Sensor Performance. GMC Truck GMC K Pickup

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC K Pickup - 4WD (CNG) 🢒 Engine 🢒 Engine Controls - 5.0L and 5.7L 🢒 DTC P0336 Crankshaft Position (CKP) Sensor Performance

Engine Controls Components
Engine Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The Crankshaft Position (CKP) sensor is supplied ignition voltage and a ground. The CKP sensor is mounted near the crankshaft and monitors a toothed crankshaft reluctor wheel. As the crankshaft spins the toothed reluctor wheel a signal is induced into the CKP sensor. The gasoline control module (VCM / PCM or ECM) and the AF ECU use the CKP signal to determine engine speed, crankshaft position and if a cylinder misfire is present.

This DTC is used to indicate no CKP reference signal is being monitored by the AF ECU while engine sensor conditions indicate the crankshaft is rotating.

Conditions for Running the DTC

•	The engine is operating on alternative fuel for an initial failure. The AF ECU will run this DTC in gasoline mode after an initial alternative fuel mode failure.

•	No AF ECU MAF sensor DTC's are set this ignition cycle.

•	MAP sensor signal indicates 105.23 kPa (31.07 in Hg) or less.

•	Mass air flow is greater than 3 grams per second for 1 second continuously.

Conditions for Setting the DTC

The AF ECU monitors no CKP reference signal during the 1 second that mass air flow is greater than 3 grams per second.

Action Taken When the DTC Sets

The AF ECU will switch-over to gasoline fuel operation. The AF ECU will not attempt alternative fuel operation until the next ignition key cycle.

•	The AF ECU will illuminate the MIL and store the DTC as History during ONE drive trip in which the diagnostic runs and fails.

•	The AF ECU will record operating conditions at the time the DTC sets. This information will be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

•	The Last Test Failed status will clear when the DTC runs and passes.

•	The AF ECU will turn OFF the MIL after 3 consecutive drive trips that the DTC runs and passes.

•	The History status will clear after 40 consecutive WARM-UP cycles with NO failures of ANY DTC.

•	All DTC Information can be cleared using a scan tool.

•	Interruption of Control Module (AF ECU / VCM / PCM or ECM) power or ground MAY clear DTC Information. Clearing DTC Information with this method is inconsistent and should not be performed.

Diagnostic Aids

For this DTC, the AF ECU uses MAF sensor airflow values in order to determine when the engine is cranking or running. The VCM uses cam sensor pulses for the VCM DTC. An AF ECU DTC (but not a VCM DTC) would result during any condition (such as a disconnected MAF sensor) that causes airflow to be indicated with the ignition ON and the engine OFF.

Fault Not Present

Fault Not Present indicates the condition that caused the DTC to set is intermittent and not currently present. Refer to Intermittent Conditions Symptom diagnosis for additional information. If any additional DTCs were stored proceed to the applicable DTC table in the order stated in the OBD System Check.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

This step determines if the condition affects the gasoline control module.

This step determines if the fault is present.

This step determines if the CKP sensor is capable of creating a good 4X Reference signal.

This step determines if the AF ECU fault is present.

This step determines if the CKP Sensor Signal circuit is good between the circuit splice and the AF ECU connector terminal.

For this DTC, the AF ECU uses MAF sensor airflow values in order to determine when the engine is cranking or running. The VCM uses cam sensor pulses for the VCM DTC. An AF ECU DTC P0336 (but not a VCM DTC) would result during any condition that causes cranking or running engine airflow to be indicated by the MAF sensor with the ignition ON and the engine OFF.

Step

Action

Value(s)

Yes

Did you perform the AF Powertrain On-Board Diagnostic (OBD) System Check?

Go to Step 2

Go to Alternative Fuels (AF) Powertrain On Board (OBD) System Check

Using the scan tool establish communication with the gasoline control module (VCM/PCM or ECM) and review DTC information.

Is this DTC also stored in the gasoline control module (VCM/PCM or ECM)?

Go to Step 3

Go to Step 8

Crank and attempt to start the engine.

Does the engine start and run?

Go to Step 9

Go to Step 4

Disconnect the CKP sensor connector.
Connect the J 35616-200 Un-powered Test Lamp between the CKP sensor Ignition Positive voltage circuit terminal and a known good ground.
Turn the ignition to the ON (run) position.

Is the test lamp illuminated?

Go to Step 5

Go to Step 13

Connect the test lamp between the CKP sensor Ignition Positive voltage circuit terminal and the CKP Sensor Ground circuit terminal.

Is the test lamp illuminated?

Go to Step 6

Go to Step 14

Turn the ignition OFF.
Supply power and ground to the CKP sensor (for testing) by using the gray jumpers contained within the J 35616 Connector test Adapter Kit and performing the following:

•	Connect the CKP sensor Ignition Positive voltage circuit terminal from the engine harness connector terminal to the CKP sensor terminal.

•	Connect the CKP Sensor Ground circuit terminal from the engine harness connector terminal to the CKP sensor terminal.

•	Connect the test leads from the J 39200 DMM between the CKP Sensor Signal circuit terminal (sensor side) and the CKP Sensor Ground circuit terminal.

Adjust the DMM to measure duty cycle by selecting AC voltage and depressing the Hz button twice.
Crank the engine.

Is the duty cycle within the specified value range?

23-43%

Go to Step 7

Go to Step 15

Inspect the 4X CKP Sensor Signal circuit for an open, short to ground, or short to voltage condition.
Disconnect the AF ECU connector that contains the 4X CKP Sensor Signal circuit in order to determine if the AF ECU is the cause of the condition.
Inspect for proper terminal contact at the gasoline control module connector and the CKP sensor connector.
Repair wiring/terminals or replace the AF ECU as necessary.

Was a repair necessary?

Go to Step 18

Go to Step 17

Using the scan tool establish communication with the AF ECU.
Clear DTC information from the AF ECU.
Turn the ignition OFF and wait 10 seconds.
Start and idle the engine.

Did this DTC set?

Go to Step 10

Go to Step 9

The fault is not present. Refer to Diagnostic Aids.

Are any DTC's stored that have not been diagnosed?

Go to the Diagnostic Trouble Code (DTC) List

Go to Intermittent Conditions

Turn the ignition OFF.
Disconnect the AF ECU connectors.
Connect the test leads from the J 39200 DMM between the CKP Sensor Signal circuit terminal and ground.
Adjust the DMM to measure duty cycle by selecting AC voltage and depressing the Hz button twice.
Crank the engine.

Is the duty cycle greater than the specified value?

23%

Go to Step 11

Go to Step 12

Inspect the AF ECU connector terminals for proper terminal contact.
Repair terminal contact as necessary.
Inspect for a condition in which air flow greater than 3 gms/sec is indicated by the MAF sensor with the ignition ON and the engine OFF. Refer to Test Descriptions

Was a repair necessary?

Go to Step 18

Go to Step 16

Repair the open 4X CKP Sensor Signal circuit between the circuit splice and the AF ECU connector terminal.

Is the repair complete?

Go to Step 18

Repair the cause of no Ignition Voltage to the CKP sensor connector.

Is the repair complete?

Go to Step 18

Repair the open CKP Sensor Ground circuit or poor terminal contact at the gasoline control module connector.

Is the repair complete?

Go to Step 18

Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement in the Engine Controls section of the gasoline service manual.
Inspect the crankshaft reluctor ring for damage. Replace the ring as necessary. Refer to Crankshaft Position Sensor Reluctor Ring Replacement in the Engine Controls section of the gasoline service manual.

Important: In order to perform the variation learn procedure a switch-over to gasoline operation is necessary. Remove the CNG 20 amp fuse in order to perform the switch-over.

Perform the Crankshaft Variation Learn Procedure. Refer to Crankshaft Position System Variation Learn in the Engine Controls section of the gasoline service manual.

Is the replacement complete?

Go to Step 18

Replace the AF ECU. Refer to Engine Control Unit Replacement .
Program (flash) the replacement control module with the correct vehicle software and calibration.

Is the replacement complete?

Go to Step 18

Important: The following control module replacement procedures must all be completed before attempting to operate the vehicle.

Replace the gasoline control module (VCM/PCM or ECM). Refer to VCM Replacement/Programming in the Engine Controls section.
Program (flash) the replacement control module with the correct vehicle software and calibration.
Perform the PASSLOCK Reprogramming Seed and Key in the Body and Accessories, Theft Deterrent section.

Important: In order to perform the variation learn procedure a switch-over to gasoline operation is necessary. Remove the CNG 20 amp fuse in order to perform the switch-over.

Perform the Crankshaft Position System Variation Learn in the Engine Controls section.

All of the above procedures are located in the gasoline service manual.

Is the replacement complete?

Go to Step 18

Using a scan tool clear the DTC information from BOTH Control modules.
Operate the vehicle under the Conditions for Running the DTC.
Using the scan tool parameter DTC STATUS, ensure that this DTC runs.

Did this DTC RUN and PASS?

System OK

Go to Step 2