Testing the camshaft position sensor and/or a Code P0340 (No cam signal al PCM) on your Chrysler (or Dodge or Plymouth or Eagle) equipped 2.0L or 2.4L 4 cylinder is an easy test that you can accomplish with a multimeter. You don't need a scan tool to follow the test steps in this article.
Also, the following camshaft position sensor test is an on car test that will verify if the CMP sensor is BAD or not while it's in action. In case you're looking for a simple Ohms (resistance) test of the Chrysler CMP... this test does not exist, since the CMP sensor is a Hall-Effect type sensor that can not be Ohmed.
The way this article is written, you'll jump right into the test... but I recommend that you first take a look at all of the sections that make up this article. Also, this article covers two types of camshaft position sensors. One is the square one used on all of the 2.0 Single Over Head Cam (SOHC) engines and the round one used on all of the 2.0L Double Over Head Cam (DOHC) and 2.4L DOHC
This article covers vehicles from Chrysler, Dodge, Eagle, Mitsubishi and Plymouth. To see if this article applies to your specific vehicle, look for the box (on the column on the right) titled ‘Applies To:’, and click on the ‘next >>’ link to scroll.
Here are the contents of this article at a quick glance:
I'm not going to go into the actual technical theory of the how the cam sensor works, after all you really don't want to reverse engineer the cam sensor. What I will give you is the basics of how it works:
The cam sensor, on your 2.0L (SOHC and DOHC) is a Hall-Effect type sensor. This means that it needs power, in the form of DC voltage and ground to produce a cam signal that the PCM can use.
Once the sensor gets these two signals and the camshaft is rotating, it starts to produce an On/Off DC voltage signal. On is when the sensor outputs 5 Volts, and Off is when this voltage drops to .3 or .5 Volts.
Each one of the three wires that connect to it have a specific job to do. One delivers power in the form of 8 Volts from the PCM. Another delivers ground. This ground is provided inside the PCM, too. The last remaining, delivers the signal, that the CMP sensor creates, to the PCM.
If your specific Chrysler (or Dodge or Eagle or Plymouth or Mitsubishi) uses the square or the round camshaft position (CMP) sensor, they are both bolted to the rear of the Cylinder Head (this is the side that faces the transaxle). The square type is secured to the head by 4 small bolts and the round one is bolted to the head with two small bolts.
You'll need to hand-turn the engine, using a 1/2 ratchet and the appropriate size socket, to turn the crankshaft pulley. You may have to jack up the vehicle to gain access to the Crankshaft Pulley. Remember to take all necessary safety precautions (like using jack stands, wearing eye-protection, etc.). OK, here's the test:
The Ignition System must be disabled and you can accomplish this by disconnecting the Ignition Coil Pack from its electrical connector. This is important! Do not proceed with the test without first unplugging the Ignition Coil Pack.
Locate the cam sensor. Now since you need to test the signals (inside the wires) of the cam sensor, you may have to remove some of the black electrical tape insulation that covers the three wires. Remove enough of it to have comfortable access to the wires.
If you disconnected the camshaft position (CMP) sensor's connector to remove some of the black electrical tape insulating the wires... reconnect the cam sensor now. To perform this test, the cam (CMP) sensor has to be connected to its connector.
With your multimeter in Volts DC mode, probe the wire that connects to the place (male spade terminal) identified with the number 3 (in the image viewer). I recommend that you use a wire-piercing probe or an appropriate tool to pierce the wire and then connect the RED multimeter lead to this tool.
To see what a what wire piercing probe tool looks like, click here: Wire Piercing Probe.
Connect the BLACK lead of the multimeter to a good ground point on the engine. Preferably, on the battery negative terminal.
When everything is set up, turn the crankshaft pulley by hand, in a clock-wise direction, using a 1/2 inch ratchet, an extension, and the appropriate socket.... while you keep your eyes on the multimeter. Do not use the starter motor to crank the engine.
If the camshaft position (CMP) sensor is working correctly, the multimeter will register an On/Off voltage of 5 Volts DC. On is when the multimeter displays 5 Volts DC and off is 0.3 to 0.5 Volts DC (this is technically considered 0 volts). The key to seeing this voltage change is to turn the crankshaft pulley slowly and steadily.
OK, let's interpret the multimeter test results you just obtained and find out what your test results mean. Choose one of the following CASES:
CASE 1: The multimeter registered the On/Off 5 Volts DC as you turned the Crankshaft Pulley: This test result indicates that the cam sensor is working fine. You have now eliminated the camshaft position (CMP) sensor as BAD.
This result also confirms that the cam sensor is getting power and ground (since without any of these two, you wouldn't see a signal).
CASE 2: The multimeter DID NOT register the On/Off 5 Volts DC as you turned the Crankshaft Pulley: Recheck all of you multimeter connections. If still your multimeter does not register the indicated On/Off voltage, then the next step is to verify that the cam sensor is getting fed power and ground. Go to CAM Sensor TEST 2.
It's important to verify that the cam (CMP) sensor is receiving power and ground before condemning it as BAD.
“A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.”