Testing the camshaft position (CMP) sensor, which is located inside the distributor, can be done with a multimeter and I'll show you how in this tutorial.
The cam sensor test in this tutorial is a very accurate way of testing the camshaft position sensor to find out if it's good or bad (without having to run out and buy a distributor to find out).
Contents of this tutorial:
NOTE: The following ignition system wiring diagram may be of help: Ignition System Wiring Diagram (1998-2000 2.5L V6 Chrysler Sebring).
Symptoms Of A Bad Cam Sensor
The camshaft position sensor inside the distributor, in conjunction with the RPM info the crankshaft position sensor provides, is used by the PCM to control injector pulse width and ignition timing.
Since the camshaft position sensor is a critical component of the ignition system, when it fails your engine won't start. Here are some more specific symptoms:
- Engine cranks but won't start.
- Trouble code lighting up the check engine light (CEL) on your instrument cluster.
- P0340: No Cam Signal at PCM.
Although the PCM is designed to register a cam sensor trouble code when the cam sensor fails, it rarely does. This is why it's a good idea to test the cam sensor with a multimeter to see if it's behind your ‘cranks but does not start’ condition.
NOTE: Don't have a multimeter? Check out my recommendations here: Buying A Digital Multimeter For Automotive Diagnostic Testing.
TEST 1: Verifying The Cam Sensor Is Getting Power
The first thing we need to do is to make sure that the camshaft position sensor is getting power.
Power is in the form of 8 Volts DC and depending on the year of your specific vehicle will be fed to the cam sensor by an orange (ORG) or an orange with white stripe (ORG/WHT) wire of the 6 pin distributor connector.
This ORG (or ORG/WHT) wire connects to distributor pin #2 of the illustration above.
NOTE: Avoid probing the front of the cam sensor's connector terminal with the multimeter's test lead (or you run the risk of damaging the terminal). My suggestion to you is to use a back-probe or a wire-piercing probe to test for this voltage. To see what a wire piercing probe looks like, go here: Wire Piercing Probe.
CIRCUIT DIAGRAM: The following ignition system wiring diagram may be of help: Ignition System Wiring Diagram (1998-2000 2.5L V6 Chrysler Sebring).
Here are the test steps:
Place your multimeter in Volts DC mode and disconnect the distributor from its engine wiring harness connector.
IMPORTANT: This test is done on the engine wiring harness distributor connector and NOT on the distributor's connector. You can further identify the engine wiring harness connector by the fact that it has female terminals.
Connect the red multimeter test lead to the ORG/WHT wire of the distributor's engine wiring harness connector using an appropriate tool.
The ORG/WHT (or ORG) wire connects to the terminal labeled with the #2 in the illustration above.
Ground the black multimeter test lead to a good Ground point on the engine or directly on the battery's negative terminal.
Have your assistant turn the key to the On position but without cranking the engine.
Your multimeter should register 8 Volts if the ORG/WHT wire is feeding the camshaft position sensor with power.
Let's interpret your test results:
CASE 1: If the multimeter showed 8 Volts. This the correct test result and lets you know that the camshaft position sensor is getting power. The next step is to make sure its Ground circuit is OK too, go to: TEST 2: Verifying The Cam Sensor Is Getting Ground.
CASE 2: If the multimeter DID NOT show 8 Volts. This indicates that the camshaft position sensor is not getting power. Without 8 Volts, the cam sensor will not work and your 2.5L Chrysler/Dodge vehicle will ‘crank but not start’.
Although it's beyond the scope of this tutorial, your next step is to find out why this voltage is missing and restore it to solve your vehicle's no start condition.