GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2007 🢒 VUE - AWD 🢒 Engine 🢒 Engine Controls and Fuel - 3.5L (L66) 🢒 DTC P0385

Circuit Description

This diagnostic monitors the signal from the crankshaft position (CKP) sensor B. The CKP sensor is a magnetic generator type sensor, producing an alternating current signal. The CKP sensor signal increases in both frequency and amplitude as the engine speed increases. The CKP sensor sends this reference signal to the powertrain control module (PCM) to indicate the crankshaft speed and position. This reference signal is used by the PCM to calculate fuel injection pulse, establish top dead center (TDC) for ignition timing and where to start ignition coil and injection sequencing. There will be no spark or fuel delivery if there is no CKP sensor signal from either CKP sensor.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0385 Crankshaft Position (CKP) Sensor B Circuit

Conditions for Running the DTC
    • DTC P0335, P0340, or P0341 are not set.
    • The engine is running.
    • DTC P0385 runs continuously once the above conditions are met.

Conditions for Setting the DTC

No crankshaft position sensor signal to the PCM for 16 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 PCM turns OFF the MIL after 3 consecutive trips without a fault.
    • The PCM clears a History DTC after 40 consecutive warm-up cycles without a fault.
    • Use the scan tool Clear DTC Information function.

Diagnostic Aids

Check for any of the following conditions:

    • The Crankshaft Position Sensor B parameter on the scan tool is normally zero counts. Only when the PCM has determined the CKP sensor A signal to be missing or unreliable, does the scan tool display a rolling count on for CKP sensor B.
    • If DTC P0335 and DTC P0385 are both setting, inspect for a loose CKP sensor assembly or damage, foreign material on the crankshaft signal rotor.

An intermittent malfunction may be caused by a fault in the CKP sensor electrical circuit. Inspect the wiring harness and the components for an intermittent condition. Refer to Intermittent Conditions .

Repair any electrical circuit faults that were found. Refer to Wiring Repairs .

The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.

Test Description

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

  1. The Diagnostic System Check - Vehicle prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

    2.

  2. This step determines whether the DTC P0385 is the result of a hard failure or an intermittent condition.

  3. This step tests the CKP sensor input circuit.

    4.

  4. After replacing the PCM new minimum throttle position and idle speed must also be established.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Clear the DTCs with a scan tool.
  3. Turn OFF the ignition for 30 seconds.
  4. Start the engine.
  5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

--

Go to Step 3

Go to Diagnostic Aids

3
  1. Turn OFF the ignition.
  2. Disconnect the crankshaft position (CKP) sensor electrical connector.
  3. Connect a test lamp between the CKP sensor B ground circuit and B+.

Did the test lamp illuminate?

--

Go to Step 4

Go to Step 7

4

  1. Connect a DMM to the ignition 1 voltage circuit of the CKP sensor B and ground.
  2. Turn ON the ignition, with the engine OFF.

Is the voltage near the specified value?

12 V

Go to Step 5

Go to Step 8

5

  1. Connect the DMM to the signal circuit of CKP sensor B and ground.
  2. Turn ON the ignition, with the engine OFF.

Is the voltage near the specified value?

5.0 V

Go to Step 10

Go to Step 6

6
  1. Test for an open or a short in the CKP sensor B signal circuit.
  2. Repair as necessary. Refer to Wiring Repairs .

Did you find and repair a condition?

--

Go to Step 13

Go to Step 9

7
  1. Repair the open in the CKP sensor B ground circuit.
  2. Repair as necessary. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 13

--

8
  1. Locate and repair the open in the ignition 1 voltage circuit of the CKP sensor B.
  2. Repair as necessary. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 13

--

9

  1. Test for an intermittent or a poor electrical connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
  2. Repair as necessary. Refer to Wiring Repairs .

Did you find and correct a condition?

--

Go to Step 13

Go to Step 12

10
  1. Test for an intermittent or a poor electrical connection at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
  2. Repair as necessary. Refer to Wiring Repairs .

Did you find and correct a condition?

--

Go to Step 13

Go to Step 11

11

Replace the crankshaft position sensor. Refer to Crankshaft Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 13

--

12

  1. Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
  2. Perform the idle learn procedure. Refer to Idle Learn .

Did you complete the replacement?

--

Go to Step 13

--

13
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 14

Go to Step 2

14

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK