How To Test The CMP Sensor (2004-2006 2.8L Chevrolet Colorado, GMC Canyon)

TEST 2: Making Sure The Camshaft Position Sensor Is Getting Power

Like any other electrical component on your Chevrolet Colorado or GMC Canyon, the CMP sensor needs power to function.

Power to the CMP sensor is in the form of 10 to 12 Volts DC and supplied by the fuel injection computer.

The wire that delivers these 10 to 12 Volts is the red (RED) wire of the CMP sensor's 3-wire connector (labeled with the letter A in the photo above).

If the RED wire delivers power to the CMP sensor, the next and last test is to make sure the CMP sensor receives Ground (TEST 3).

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the camshaft position sensor from its electrical connector.

3. 3

   Connect the red multimeter test lead to the wire identified with the letter A.

4. 4

   Connect the black multimeter test lead to the battery negative (-) terminal.

5. 5

   Turn the key ON but don't crank or start the engine. This will power up the connector.

6. 6

   Your multimeter should give you a reading of 10 to 12 Volts DC.

Let's examine your test results:

CASE 1: The multimeter registered 10-12 Volts. This confirms that the camshaft position sensor is getting power.

The next thing to do, is to check that the camshaft position sensor is getting Ground from the computer too. For this test go to: TEST 3: Making Sure The Camshaft Position Sensor Is Getting Ground.

CASE 2: The multimeter DID NOT register 10-12 Volts. The camshaft position sensor will not create a CMP signal without power.

With this test result, you have eliminated the camshaft position sensor itself as the cause of the camshaft position sensor code (P0340 Camshaft Position Sensor Circuit or P0341 Camshaft Position Sensor Performance).

Although it's beyond the scope of this tutorial, your next step is to resolve this lack of 12 Volts.

TEST 3: Making Sure The Camshaft Position Sensor Is Getting Ground

So far, you have confirmed:

• The CMP sensor is not producing an ON/OFF voltage pulse (TEST 1).
• The CMP sensor is receiving 10 to 12 Volts (TEST 2).

In this last test section, you'll check that the pink with black stripe (PNK/BLK) wire delivers Ground to the CMP sensor.

IMPORTANT: The fuel injection computer is the component that supplies Ground to the camshaft position sensor. For this reason, be careful not to apply 12 Volts (battery power) to this wire, or you'll fry the fuel injection computer. The multimeter voltage test I'm recommending is a safe way of checking the presence of Ground in the wire.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the camshaft position sensor from its electrical connector.

3. 3

   Connect the black multimeter test lead to the wire identified with the letter C.

4. 4

   Connect the red multimeter test lead to the battery positive (+) terminal.

5. 5

   Turn the key ON but don't crank or start the engine. This will power up the fuel injection computer.

6. 6

   Your multimeter should give you a reading of 10 to 12 Volts DC.

Let's examine your test results:

CASE 1: Your multimeter registered 10 to 12 Volts DC. This test result lets you know that the fuel injection computer is providing Ground for the camshaft position sensor.

You can conclude that your Colorado or Canyon's camshaft position sensor is defective only if you have:

• Confirmed that the sensor is not producing an ON/OFF voltage signal (TEST 1).
• Confirmed that the sensor is getting power (TEST 2).
• Confirmed that the sensor is getting Ground (this test section).

CASE 2: Your multimeter DID NOT register 10 to 12 Volts DC. The camshaft position sensor will not create a CMP signal without Ground.

With this test result, you have now eliminated the camshaft position sensor itself as the cause of the camshaft position sensor code (P0340 Camshaft Position Sensor Circuit or P0341 Camshaft Position Sensor Performance).

Although it's beyond the scope of this tutorial, your next step is to resolve this lack of Ground.

More 2.8L Chevrolet Colorado (GMC Canyon) Tutorials

You can find a complete list of 2.8L Chevrolet Colorado (GMC Canyon) tutorials and wiring diagrams here:

• GM 2.8L Vortec 4-Cylinder Index of Articles.

Here's a list of articles you'll find there:

• How To Test The Electronic Throttle Body (2004-2006 2.8L Chevrolet Colorado, GMC Canyon).
• How To Test Engine Compression (2004-2006 2.8L Chevrolet Colorado, GMC Canyon).
• Blown Head Gasket Tests (2004-2006 2.8L Chevrolet Colorado, GMC Canyon).
• TAC Throttle Body Wiring Diagram (2004-2006 2.8L Chevrolet Colorado, GMC Canyon).