GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Cavalier (CNG) 🢒 DTC 🢒 DTC P0336

Circuit Description

The Crankshaft Position (CKP) sensor is connected to the Ignition Control (IC) module. The CKP sensor is mounted near the crankshaft and monitors a toothed crankshaft reluctor wheel. When the toothed reluctor wheel, and the crankshaft, spins, a signal is induced into the CKP sensor. Based upon the signal that is received from the CKP sensor the IC module supplies a CKP signal on the CKP 7X reference circuit. For each one engine revolution the IC module pulses the CKP 7X reference circuit 7 times. The gasoline control module (VCM/PCM or ECM) and the AF ECM use the CKP 7X 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 ECM 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 ECM will run this DTC in gasoline mode after an initial alternative fuel mode failure.
    • The MAP sensor signal indicates 105.23 kPa (31.07 in Hg) or less.
    • A cam signal is monitored indicating the engine is cranking or running.

Conditions for Setting the DTC

The AF ECM monitors no CKP reference signal when a cam sensor signal is monitored.

Action Taken When the DTC Sets

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

    • The Alternative Fuels ECM will illuminate the MIL and store the DTC as History during 1 drive trip in which the diagnostic runs and fails.
    • The Alternative Fuels ECM 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 Alternative Fuels ECM 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 with a scan tool.

Diagnostic Aids

Intermittent Condition

A fault not present indicates the condition that caused the DTC to set is intermittent and not currently present. Refer to Intermittent Conditions diagnostic information located in Symptoms-Engine Controls. If any additional DTCs were stored, proceed to the applicable DTC table in the order stated in the Diagnostic System Check - Alternative Fuels (Engine Controls) .

Test Description

The number below refer to the step number on the diagnostic table.

  1. Use the Bi-Fuel Supplement Engine Controls schematics whenever performing diagnostic procedures from the J platform service manual.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Alternative Fuels Engine Controls Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Alternative Fuels (Engine Controls)

2

Crank and attempt to start the engine.

Does the engine start and run?

Go to Step 3

Go to Engine Cranks but Does Not Run

3
  1. Using the scan tool establish communication with the gasoline control module (VCM/PCM or ECM).
  2. Inspect for stored powertrain DTCs.

Are any gasoline powertrain control module DTCs set?

Go to Diagnostic Trouble Code (DTC) Types in Engine Controls-2.2L (LN2) in the J Platform Service Manual

Go to Step 4

4
  1. Using the scan tool establish communication with the AF ECM.
  2. Clear DTC Information from the AF ECM.
  3. Turn the ignition OFF and wait 10 seconds.
  4. Start and idle the engine.

Did DTC P0336 set?

Go to Step 6

Go to Step 5

5

The fault is not present. Refer to Diagnostic Aids.

Are any DTCs stored that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

Go to Intermittent Conditions

6
  1. Inspect the 7X CKP sensor signal circuit for an open or high resistance between the circuit splice and the AF ECM connector terminal.
  2. Inspect for poor terminal contact at the AF ECM connector.
  3. Repair the wiring or terminal contact as necessary.

Was a repair necessary?

Go to Step 8

Go to Step 7

7
  1. Replace the AF ECM. Refer to Alternative Fuels Engine Control Module Replacement .
  2. Program -- flash the replacement control module with the correct vehicle software and calibration.

Is the replacement complete?

Go to Step 8

--

8
  1. Using a scan tool clear the DTC information from BOTH Control Modules.
  2. Operate the vehicle under the Conditions for Running the DTC.
  3. Using the scan tool parameter DTC STATUS, ensure that this DTC runs.

Did this DTC RUN and PASS?

System OK

Go to Step 2