GM Service Manual Online
For 1990-2009 cars only

Object Number: 185025  Size: LF
Engine Controls Components
Ignition System
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The crankshaft position sensor is a hall-effect type sensor that monitors crankshaft position and speed. There are four teeth 90 degrees apart on the front of the crankshaft sprocket that induce a pulse in the sensor which is transmitted to the PCM. There is a physical one to one correspondence between the pump cam and crankshaft.

Conditions for Setting the DTC

    • The PCM performs this DTC diagnostic continuously.
    • The number of consecutive missing crank pulses are greater than or equal to 8.
    • All diagnostic set conditions met for 2 seconds.

Action Taken When the DTC Sets

    • The PCM illuminates the malfunction indicator lamp (MIL) on the first consecutive drive trip that the diagnostic runs and fails.
    • The Freeze Frame records the operating conditions at the time of failure and updates the Failure Records.
    • The PCM will activate Back Up fuel.

Conditions for Clearing the MIL/DTC

    • The PCM will turn the MIL off after three consecutive trips without a fault condition.
    • A History DTC will clear after forty consecutive warm up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle.
    • The use of a scan tool

Diagnostic Aids

When the PCM is in backup fuel, long crank times, fast idle and poor performance conditions will exist. Check for a good connection at crankshaft position sensor and at the PCM. Many intermittent problems are caused by poor electrical connections or wiring. When attempting to diagnose an intermittent problem, always begin by trying to reproduce the conditions under which the failure occurs. This usually involves raising the engine to a higher temperature or operating it near RPM that the problem occurs. Since heat and vibration are often the cause of an intermittent, this may bring out the failure.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

  1. This step will determine if DTC P0335 is the result of a hard failure or an intermittent condition.

  2. This step checks the 5 volt reference circuit (the 5 volt reference may vary slightly).

  3. This step checks the ground circuit.

Step

Action

Value(s)

Yes

No

1

Important: Before clearing any DTCs, use the scan tool Capture Info to save freeze frame and failure records for reference, as the scan tool loses data when using the Clear Info function.

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Start and idle the engine.
  2. Observe the Crank Ref. Missed display on the scan tool.

Does the scan tool display the specified value?

8

Go to Step 4

Go to Step 3

3

The DTC is intermittent. If no additional DTCs are stored, refer to the Applicable DTC Table(s) first.

Are any additional DTCs stored?

--

Go to the Applicable DTC Table

Go to Diagnostic Aids

4

  1. Turn the ignition OFF.
  2. Disconnect the CKP sensor electrical connector.
  3. Turn the ignition ON leaving the engine OFF.
  4. With a DMM J 39200 , measure the voltage between the CKP 5 volt reference circuit and chassis ground.

Is the voltage within the specified range?

4.8-5.2V

Go to Step 5

Go to Step 8

5

Probe the sensor ground circuit with a test light connected to B+.

Is the test light ON?

--

Go to Step 6

Go to Step 9

6

  1. Reconnect the CKP sensor.
  2. Back probe the CKP signal circuit at the PCM with a DMM J 39200 connected to ground.
  3. Crank the engine.

Is the voltage within the specified value?

4.2-4.5V

Go to Step 14

Go to Step 7

7

Is the voltage greater than the specified value?

4.2-4.5V

Go to Step 12

Go to Step 11

8

  1. Turn the ignition OFF.
  2. Disconnect the PCM, and check the CKP 5 volt reference circuit for an open, short to ground, or short to the sensor ground circuit.
  3. If the CKP 5 volt reference circuit is open or shorted to ground, repair it as necessary.

Was a repair performed?

--

Go to Step 17

Go to Step 10

9

  1. Check for an open or a proper sensor ground terminal connection at the PCM.
  2. If a problem is found, repair the problem as necessary.

Was a repair performed?

--

Go to Step 17

Go to Step 16

10

Check the CKP 5 volt reference circuit for a proper connection at the PCM and replace the terminal if necessary.

Did the terminal require replacement?

--

Go to Step 17

Go to Step 16

11

  1. Turn the ignition OFF.
  2. Disconnect the PCM and check the CKP signal circuit for an open, short to ground, or short to the sensor ground circuit.
  3. Check the terminal connections at the CKP sensor for damage or a poor connection.
  4. If a problem is found, repair the problem as necessary.

Was a repair performed?

--

Go to Step 17

Go to Step 15

12

  1. Disconnect the CKP sensor pigtail connector.
  2. Turn the ignition ON leaving the engine OFF.
  3. With the J 39200 connected to ground, probe the CKP signal circuit at the engine harness connector.

Is there voltage present on the CKP sensor signal circuit?

--

Go to Step 13

Go to Step 14

13

Repair the short to voltage on the CKP sensor signal circuit.

Is the action complete?

--

Go to Step 17

--

14

Check the CKP signal circuit for a proper connection at the PCM and replace the terminal if necessary.

Did the terminal require replacement?

--

Go to Step 17

Go to Step 16

15

Replace the Crankshaft position sensor. Refer to Crankshaft Position Sensor Replacement . After replacing the sensor, the PCM must be programmed with a new TDC Offset. Refer to Fuel Injection Pump Top Dead Center Offset Adjustment .

Is the action complete?

--

Go to Step 17

--

16

Replace the PCM.

Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 17

--

17

  1. Using the Scan tool, clear the DTCs.
  2. Start the engine and idle at normal operating temperature.
  3. Select DTC, Specific, then enter the DTC number which was set.
  4. Operate the vehicle, within the Conditions for Setting this DTC, until the Scan Tool indicates the diagnostic Ran.

Does the Scan tool indicate the diagnostic Passed?

--

Go to Step 18

Go to Step 2

18

Does the Scan tool display any additional undiagnosed DTCs?

--

Go to the Applicable DTC Table

System OK