The camshaft position (CMP) sensor, which is also known as the distributor pickup coil, can easily be tested with a multimeter.
In this tutorial, I'm gonna' explain the three tests you need to perform to 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 (CMP) Sensor.
- Circuit Descriptions Of The Camshaft Position Sensor.
- TEST 1: Testing The Camshaft Position Signal.
- TEST 2: Making Sure The CMP Sensor Has Power.
- TEST 3: Making Sure The CMP Sensor Has 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: 1996-1997.
IGNITION COIL TEST: The following tutorial will help you test the ignition coil: How To Test The Ignition Coil -No Start Tests (Chrysler 3.9L, 5.2L, 5.9L) (at: troubleshootmyvehicle.com).
WIRING DIAGRAM: You can find the ignition system wiring diagrams here:
- Ignition System Circuit Diagram (1996 5.2L V8 Dodge Dakota).
- Ignition System Circuit Diagram (1997-1999 5.2L Dodge Dakota And Durango).
Symptoms Of A Bad Camshaft Position (CMP) Sensor
The camshaft position (CMP) sensor is a critical component of your 5.2L V8 Dodge Dakota's ignition system. The fuel injection computer uses the CMP signal and the CKP signal to start activating the ignition coil and to start injecting fuel into the engine's cylinders.
So when the camshaft position sensor fails, the engine is not gonna' start due to a lack of spark and fuel injection.
In most cases, you're also gonna' see the following diagnostic trouble code lighting up the check engine light:
- 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
The camshaft position sensor needs power, Ground to produce its signal. As such, it has 3 wires coming out of its electrical connector.
In the table below you'll find a short description of each of the 3 wires:
| 1996-1997 Camshaft Position Sensor Connector | ||
|---|---|---|
| Pin | Wire Color | Description |
| 1 | Violet with white stripe (VIO/WHT) | Power (5 Volts DC) |
| 2 | Black with light blue stripe (BLK/LT BLU) | Sensor Ground |
| 3 | Tan with yellow stripe (TAN/YEL) | CMP Signal |
The following ignition system wiring diagrams will further help you identify the camshaft position sensor circuits:
- Ignition System Circuit Diagram (1996 5.2L V8 Dodge Dakota).
- Ignition System Circuit Diagram (1997-1999 5.2L Dodge Dakota And Durango).
The camshaft position sensor creates an ON/OFF voltage signal as the engine turns. ON is when the CMP signal is at 5 Volts DC. OFF is when the CMP signal is at 0 Volts.
The cool thing is that we can see this ON/OFF voltage with a multimeter, and this is how we're gonna' test it.
TEST 1: Testing The Camshaft Position Signal
The wire that carries the camshaft position (CMP) signal, to your 5.2L V8 Dodge Dakota's fuel injection computer, is the tan with yellow stripe (TAN/YEL) wire.
The TAN/YEL wire is the wire labeled with the number 3 in the photo above.
It can be easy to confuse the CMP sensor's connector with the CKP sensor's connector. The camshaft position (CMP) sensor is located in the distributor and the crankshaft position (CKP) sensor is bolted onto the transmission bell housing. Both of the connectors are in the same location so take care to test the correct connector.
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:
- 1
Place your multimeter in Volts DC mode.
- 2
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. - 3
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. - 4
Connect the black multimeter test lead directly on the battery negative (-) terminal.
- 5
Have your helper crank the engine for a few seconds once the multimeter test lead connections are set up.
- 6
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 CMP Sensor Has Power.