How To Test The CMP Sensor -P0340 (1996-2000 2.4L Dodge And Plymouth Minivan)

Testing the camshaft position (CMP) sensor and DTC P0340 on your 2.4L Dodge or Plymouth minivan is not that difficult —and you don't need a scan tool to do it. A simple multimeter is all it takes.

In this guide, I'll walk you through each test step-by-step so you can confidently figure out whether the CMP sensor is working or not.

Just a heads-up: this is a Hall-Effect type sensor, which means you can't test it with a standard resistance (Ohms) check like the 2-wire variable reluctor type sensors.

And if you'd rather skip the testing and just swap it out, no problem —I'll point you to where you can get a replacement at a good price.

APPLIES TO: This tutorial applies to the following vehicles:

• 2.4L Dodge Caravan: 1996, 1997, 1998, 1999, 2000.
• 2.4L Dodge Grand Caravan: 1996, 1997, 1998.
• 2.4L Plymouth Voyager: 1996, 1997, 1998, 1999, 2000.
• 2.4L Plymouth Grand Voyager: 1996, 1997, 1998.

WIRING DIAGRAMS:

• Ignition System Wiring Diagram (1996-1997 2.4L Dodge And Plymouth Minivan).
• Ignition System Wiring Diagram (1998-1999 2.4L Dodge And Plymouth Minivan).
• Ignition System Wiring Diagram (2000 2.4L Dodge And Plymouth Minivan).

IGNITION SYSTEM TESTS:

• Testing The Crankshaft Position Sensor (1996-2002 2.4L Caravan, Grand Caravan, Voyager, Grand Voyager).
• How To Test The Ignition Coil (1996-2007 2.4L Caravan, Grand Caravan, Voyager, Grand Voyager).

OTHER CMP SENSOR TESTS:

• How To Test The CMP Sensor -P0340 (2001-2002 2.4L Chrysler And Dodge Minivan).
• How To Test The CMP Sensor -P0340 (2003-2007 2.4L Chrysler And Dodge Minivan).

ENGINE NO-START DIAGNOSTICS:

• How To Test An Engine No-Start (1996-2007 2.4L Chrysler, Dodge, And Plymouth Minivan).

Common Symptoms Of A Bad CMP Sensor (P0340)

If the camshaft position (CMP) sensor on your 2.4L Caravan or Voyager is completely toast, you'll see:

• Engine no-start: The engine is not gonna start no matter how long you crank it.
• DTC P0340: PCM isn't seeing any signal from the camshaft sensor, so it registers this code.

Now, when it's beginning to fail, you'll see one or more of the following:

• Engine starts then dies: Sometimes the engine fires up but shuts down almost instantly —this often points to an intermittent CMP signal dropout.
• Check Engine Light On: A faulty CMP sensor usually trips the check engine light. You'll likely find a fault code stored in the PCM.
  • P0340: PCM isn't seeing any signal from the camshaft sensor.
• Erratic Engine Behavior: Expect performance issues like rough running, misfires, or the engine struggling during acceleration if the CMP sensor is acting up.

How The CMP Sensor Works

The camshaft position (CMP) sensor, on your 2.4L Caravan or Voyager, is a Hall-Effect sensor —which means it needs both power (8V) and Ground to function.

Both of these come straight from your minivan's PCM (Powertrain Control Module).

Once it's powered up and the camshaft starts turning, the CMP sensor generates a pulsed DC signal —switching between high (ON) and low (OFF) voltage— that the PCM uses to start and control ignition timing and fuel injection.

• When the signal is ON, the sensor outputs around 5 Volts.
• When it's OFF, that voltage drops down to about 0.3 to 0.5 Volts.

This ON/OFF pattern tells the PCM the exact position of the camshaft, and —together with the CKP sensor signal— helps it fire the injectors and spark plugs at just the right moment.

But when the PCM stops receiving this signal, it sets a code P0340 and shuts down the ASD relay, cutting off ignition spark and fuel injection to the engine.

Should I Just Replace The CMP Sensor Without Testing It?

To be honest with you —most people (including plenty of repair shops) don't even bother testing the camshaft position sensor when they see a P0340 trouble code pop up in the PCM's memory. They just replace it.

And truth be told, that approach works. In most cases, slapping on a new CMP sensor solves the issue right away, no further diagnosis needed.

So if you're thinking about skipping the tests and going straight for a replacement, there's absolutely nothing wrong with that.

If that's your plan, I've included links below to known, trusted brands —no cheap knock-offs. You'll save a few bucks and avoid the guesswork.

But... If you want to be sure the sensor is actually the problem before spending money, I'll walk you through the exact steps in this tutorial to test it properly with just a multimeter.

Where To Buy The CMP Sensor And Save

Camshaft Position Sensor Connector Pinout

CMP Sensor Circuits
Terminal	Wire	Description
1	Orange (ORG)	8 Volts DC
2	Black with light blue stripe (BLK/LT BLU)	Ground
3	Tan with yellow stripe (TAN/YEL)	CMP Sensor Signal

TEST 1: Checking The CMP Signal With A Multimeter

First up, we're going to test whether the camshaft position (CMP) sensor on your 2.4L minivan is generating a switching voltage signal as the engine turns over manually.

This sensor creates a pulsed signal that flips between 5 Volts (ON) and about 0.3–0.5 Volts (OFF). To catch this change on your multimeter, the engine needs to be rotated by hand —not with the starter motor.

You'll need a 1/2" drive ratchet and socket to turn the crankshaft pulley bolt. If you try to use the starter, the signal will flash too fast for your multimeter to display anything readable.

If you don't have a multimeter, or thinking about upgrading, here's the one I personally use and recommend: Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (via Amazon).

CAUTION: If you need to lift the front of the minivan to access the crankshaft pulley bolt, be sure to use jack stands. Never rely solely on the jack to hold the van up!

NOTE: This test is done with the sensor plugged in. To tap into the signal wire, you'll need to use a back probe (on the connector) or a wire piercing probe (on the wire). You can see what that tool looks like and where to get one here: Wire Piercing Probe.

Let's get started:

1. 1

   Unplug the ignition coil pack before you do anything else.
   
   IMPORTANT: Don't skip this step. Disconnecting the coil pack ensures the engine won't accidentally start while you're cranking it by hand.

2. 2

   Set your multimeter to Volts DC mode.

3. 3

   Attach the black multimeter lead to the negative (-) terminal on the battery.

4. 4

   Connect the red lead to the TAN/YEL wire at the CMP sensor's connector.
   
   You can back probe the connector or pierce the wire insulation using a specialized probe.

5. 5

   Slowly rotate the crankshaft clockwise using your ratchet, extension, and socket while watching the multimeter screen.
   
   IMPORTANT: Do not use the starter motor to crank the engine —it must be turned slowly by hand to see the ON/OFF voltage pulses on your multimeter.

6. 6

   Watch for a voltage signal that jumps between 5V and 0V.
   
   When the sensor signal is ON, you'll see 5 Volts DC. When it's OFF, it will drop to about 0.3 to 0.5 Volts —which we'll consider as 0V for this test.
   
   IMPORTANT: You'll need to rotate the crankshaft pulley at least two full revolutions to complete the signal test.

Now, let's break down what your results mean:

CASE 1: You saw the voltage switching ON and OFF as you turned the crankshaft pulley. That means the CMP sensor is alive and well.

This also confirms the sensor is receiving both power and Ground from the PCM, since you wouldn't get a signal without both of those in place.

So if you're seeing that ON/OFF output while chasing a code P0340, the sensor itself isn't the problem.

CASE 2: You didn't see any ON/OFF voltage at all. Double-check all your multimeter connections and probe placement.

If you're still not seeing that pulsed signal, the next step is to verify that the CMP sensor is actually getting power. Head over to: TEST 2: Making Sure The CMP Sensor Is Getting 8 Volts.