GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2007 🢒 VUE - FWD 🢒 Engine 🢒 Engine Controls and Fuel - 2.2L (L61) 🢒 Crankshaft Position Sensor System Diagnosis

Circuit Description

The crankshaft position (CKP) sensor is a variable reluctance sensor. The CKP sensor indicates the crankshaft speed and position. The CKP sensor produces an AC voltage of different amplitude and frequency. The frequency depends on the velocity of the crankshaft. The AC voltage output depends on the crankshaft position and the battery voltage. The CKP sensor works in conjunction with a 7X reluctor wheel attached to the crankshaft. The CKP sensor connects to the engine control module (ECM) through the following circuits:

    • The CKP sensor signal circuit
    • The low reference circuit

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

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

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Attempt to start the engine.

Does the engine start and run?

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Go to Step 3

Go to Step 4

3
  1. Turn OFF the ignition.
  2. Disconnect the engine control module (ECM).
  3. Measure the resistance between the signal circuit and the low reference circuit of the crankshaft position (CKP) sensor with a DMM. Refer to Circuit Testing.

Is the resistance within the specified range?

500-900 ohms

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 11

4
  1. Turn OFF the ignition.
  2. Crank the engine.
  3. Observe the CMP Resync Counter parameter with a scan tool.

Does the CMP Resync Counter increment?

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Go to Step 12

Go to Step 5

5

Test the signal circuit for the following conditions:

    • A short to voltage
    • An open
    • High resistance

Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

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Go to Step 13

Go to Step 6

6

Test the low reference circuit for the following conditions:

    • A short to voltage
    • An open
    • High resistance
    • The CKP sensor circuits shorted together

Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

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Go to Step 13

Go to Step 7

7

Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

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Go to Step 13

Go to Step 8

8

Test for an intermittent and for a poor connection at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

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Go to Step 13

Go to Step 9

9
  1. Remove the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
  2. Visually inspect the CKP sensor for the following conditions:
    3. • Physical damage
    • Excessive play or looseness
    • Improper installation
    • Foreign material passing between the CKP sensor and the reluctor wheel
    • Electromagnetic interference in the CKP sensor circuits

Did you find and correct the condition?

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Go to Step 13

Go to Step 10

10

Inspect the CKP reluctor wheel for the following conditions:

    • Physical damage
    • Excessive end play or looseness
    • Improper installation

Did you find and correct the condition?

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Go to Step 13

Go to Step 11

11

Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement .

Did you complete the replacement?

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Go to Step 13

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12

Replace the ECM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

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Go to Step 13

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13
  1. Turn OFF the ignition for 30 seconds.
  2. Start the engine and operate the vehicle.
  3. Observe the malfunction indicator lamp (MIL), vehicle performance, and driveability.

Does the vehicle operate normally, with no MIL illumination?

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System OK

Go to Step 2