Circuit Description

WARNING: This page is about a different car, the 2004 Pontiac Sunfire and 2004 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

The crankshaft position (CKP) sensor is a variable reluctance sensor. The crankshaft position (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 battery voltage. The CKP sensor works in conjunction with a 7X reluctor wheel attached to the crankshaft. The CKP sensor connects to the powertrain control module (PCM) through the following circuits:

The CKP sensor signal
The low reference

Crankshaft Position Sensor (CKP) System Diagnosis

Step	Action	Value(s)	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check-Engine Controls?	-	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	Attempt to start the engine. Does the engine start and run?	-	Go to Step 3	Go to Step 4
3	Turn OFF the ignition. Disconnect the powertrain control module (PCM). 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 in Wiring Systems. Is the resistance within the specified range?	500-900 ohm	Go to Intermittent Conditions	Go to Step 11
4	Crank the engine. Observe the CKP Active Counter parameter with a scan tool. Does the CKP Active Counter increment?	-	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 in Wiring Systems. Did you find and correct the condition?	-	Go to Step 13	Go to Step 6
6	Test the low reference circuit for the following conditions: An open High resistance The CKP sensor circuits shorted together Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 13	Go to Step 7
7	Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	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 in Wiring Systems. Did you find and correct the condition?	-	Go to Step 13	Go to Step 9
9	Remove the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Visually inspect the CKP sensor for the following conditions: Physical damage Excessive play or looseness Improper installation Foreign material passing between the CKP sensor and the reluctor wheel Excessive air gap between the CKP sensor and the reluctor wheel Electromagnetic interference in the CKP sensor circuits Did you find and correct the condition?	-	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 Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. Did you find and correct the condition?	-	Go to Step 13	Go to Step 11
11	Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Did you complete the replacement?	-	Go to Step 13	-
12	Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . Did you complete the replacement?	-	Go to Step 13	-
13	Turn OFF the ignition for 30 seconds. Start the engine and operate the vehicle. Observe the malfunction indicator lamp (MIL), vehicle performance, and driveability. Does the vehicle operate normally, with no MIL illumination?	-	System OK	Go to Step 2