The camshaft position sensor, which is located in the distributor, can be easily tested and in this tutorial I'll show you how.
The camshaft position sensor test is done with a multimeter and with your test results you'll be able to easily find out if it's bad or not.
NOTE: The camshaft position sensor is also known as the distributor pickup coil.
Contents of this tutorial:
- Symptoms Of A Bad Camshaft Position Sensor.
- Circuit Descriptions Of The Camshaft Position Sensor.
- TEST 1: Testing The Camshaft Position Signal.
- TEST 2: Making Sure The Camshaft Position Sensor Is Getting 8 Volts.
- TEST 3: Making Sure The Camshaft Position Sensor Is Getting Ground.
- Where To Buy The Camshaft Position Sensor.
- More 5.2L Dodge Dakota Tutorials.
APPLIES TO: This tutorial applies to the following vehicles since they use the exact same camshaft position (CMP) sensor:
- 5.2L V8 Dodge Dakota: 1992, 1993, 1994, 1995.
Symptoms Of A Bad Camshaft Position Sensor
The fuel injection computer uses the crankshaft position sensor and the camshaft position sensor (distributor pickup coil) to activate the ignition coil and the fuel injectors.
Since the camshaft position sensor is such a critical component of the ignition system, when it fails the engine is not gonna' start.
You may see the following diagnostic trouble code stored in the fuel injection computer's memory.
- P0340: No Camshaft Signal At PCM (1996-1997 OBD II system).
If you have a code reader or a scan tool, check for codes. To test the actual camshaft position sensor, a scan tool is not required.
Circuit Descriptions Of The Camshaft Position Sensor
You'll notice that the camshaft position sensor has 3 wires coming out of its connector. This is because two of those three wires feed it with power and Ground. The third wire carries to CMP signal to the fuel injection computer.
In the table below you'll find a short description of each of the 3 wires:
|1992-1995 Camshaft Position Sensor Connector|
|1||Orange (ORG)||Power (5 Volts DC)|
|2||Black with light blue stripe (BLK/LT BLU)||Sensor Ground|
|3||Tan with yellow stripe (TAN/YEL)||CMP Signal|
To successfully diagnose the camshaft position (CMP) sensor as good or bad, it's important to know that it creates an ON/OFF voltage signal as the engine turns.
To be a bit more specific, ON is when the CMP signal is at 5 Volts DC. OFF is when the CMP signal is at 0 Volts.
We can easily check for this ON/OFF voltage with a multimeter and as we crank the engine, and this is how we're gonna' test it.
TEST 1: Testing The Camshaft Position Signal
For our first test, we're gonna' see if the CMP signal is present in the tan with yellow stripe (YEL/TAN) wire as the engine is cranking.
In the photo above, the TAN/YEL wire is identified with the number 3.
Specifically, we need to see that the voltage signal is switching between 5 Volts and 0 Volts.
IMPORTANT: The camshaft position sensor must be connected to its engine harness connector for this test to work. You'll need to connect your multimeter test lead to a back probe or a wire piercing probe to read the CMP signal. You can see an example of a wire piercing probe here: Wire Piercing Probe Review (Power Probe PWPPPPP01).
NOTE: Don't have a multimeter or need to upgrade yours? Check out my recommendation: Buying A Digital Multimeter For Automotive Diagnostic Testing.
These are the test steps:
Place your multimeter in Volts DC mode.
Disconnect the ignition coil from its electrical connector. This is an important safety precaution!
NOTE: Don't remove the distributor cap from the distributor. The distributor cap must be in place to hold down the camshaft position sensor.
With the red multimeter test lead, probe the tan with yellow stripe (TAN/YEL) wire of the cam sensor connector.
NOTE: The camshaft position sensor must remain connected to its engine wiring harness connector to be able to read its signal.
Connect the black multimeter test lead directly on the battery negative (-) terminal.
Have your helper crank the engine for a few seconds once the multimeter test lead connections are set up.
Your multimeter should see the voltage switch between 5 Volts and 0 Volts DC as the engine is cranking.
Let's examine your CMP signal test result:
CASE 1: The multimeter read the indicated ON/OFF DC voltage. This is the correct and expected test result and tells you that the camshaft position sensor is functioning correctly.
Since the camshaft position sensor IS NOT defective, something else is causing your 5.2L V8 Dakota to not start.
CASE 2: The multimeter DID NOT read the indicated ON/OFF DC voltage. This test result usually means that the camshaft position sensor is defective.
Before you replace it, make sure it's getting power and Ground. For the next test go to: TEST 2: Making Sure The Camshaft Position Sensor Is Getting 8 Volts.