When the camshaft position sensor (CMP) goes bad on your 2.4L Dodge or Plymouth minivan, it usually sets a P0340 trouble code in the PCM and the engine isn't gonna start.
If you're chasing a P0340 or suspect the CMP sensor is behind the engine's no-start, don't worry —testing it isn't complicated.
You won't need a scan tool to do it either (though if you've got one, that's awesome, it's must-have tool). I'll walk you through how to check the CMP signal using a regular multimeter.
And hey, if you'd rather just replace the sensor and be done with it, that's totally fine too —I've included links below to help you find a quality replacement at a good price.
Contents of this tutorial:
- Common Symptoms Of A Bad CMP Sensor (P0340).
- How The CMP Sensor Works.
- Should I Just Replace The CMP Sensor Without Testing It?
- Where To Buy The CMP Sensor And Save.
- Camshaft Position Sensor Connector Pinout.
- TEST 1: Checking The CMP Signal With A Multimeter.
- TEST 2: Making Sure The CMP Sensor Is Getting 5 Volts.
- TEST 3: Making Sure The CMP Sensor Is Getting Ground.
- More 2.4L Chrysler, Dodge, And Plymouth Minivan Tutorials.
APPLIES TO: This tutorial applies to the following vehicles:
- 2.4L Chrysler Voyager: 2003.
- 2.4L Dodge Caravan: 2003, 2004, 2005, 2006, 2007.
WIRING DIAGRAMS:
IGNITION SYSTEM TESTS:
- How To Test The CKP Sensor -P0320, P0335, P0339 (2003-2007 2.4L Chrysler And Dodge Minivan).
- 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 (1996-2000 2.4L Dodge And Plymouth Minivan).
- How To Test The CMP Sensor -P0340 (2001-2002 2.4L Chrysler And Dodge Minivan).
Common Symptoms Of A Bad CMP Sensor (P0340)
When the camshaft position (CMP) sensor completely fails on your 2003-2007 2.4L Dodge Caravan or Chrysler Voyager, you'll usually run into two obvious issues:
- Cranks but won't start: The engine turns over but never actually starts —no spark, no fuel injection.
- DTC P0340: The PCM isn't seeing a cam signal, so it logs this code and disables ignition and fuel output.
If the sensor is starting to go out —but hasn't failed completely— the symptoms may vary a bit. Here's what to look out for:
- Starts, then dies: The engine might fire up briefly, then shut off as soon as the signal drops out.
- Check Engine Light (CEL) on: A weak or intermittent CMP signal usually sets a code like:
- P0340: Camshaft signal missing at PCM input.
- Unstable engine performance: You might notice things like surging, rough idle, hesitation, or misfires —all signs the PCM is struggling to manage ignition timing and fuel injection.
How The CMP Sensor Works
On the 2003-2007 2.4L Caravan or Voyager, the camshaft position sensor (CMP) is a Hall-Effect type sensor —meaning it needs a steady 5 Volt supply and a Ground to function properly. Both signals are provided directly by the PCM (Powertrain Control Module).
As the camshaft turns —whether the engine is cranking or running— the CMP sensor generates a pulsed DC voltage signal that flips ON and OFF.
- ON: The signal reads around 5 Volts.
- OFF: It drops to about 0.3 to 0.5 Volts.
This pulsing signal helps the PCM determine the exact position of the camshaft, and together with the crankshaft position (CKP) sensor signal, it allows the PCM to precisely control spark and fuel delivery.
When the CMP signal is missing —whether you're cranking the engine or its running— the PCM can't calculate ignition timing and fuel delivery, which leads to a no-start condition and triggers a CMP sensor P0340 trouble code.
Should I Just Replace The CMP Sensor Without Testing It?
I'll be honest with you —when code P0340 shows up in the PCM's memory, most people (including plenty of shops) skip the diagnostics and go straight to replacing the camshaft position sensor.
And to be fair, that approach works more often than not. In most cases, installing a new CMP sensor clears the code and gets the engine running again without any extra steps.
So if you're thinking of just replacing it without running tests, go for it. I've included links below to trusted-name brand sensors —no cheap knockoffs— so you can save a few bucks and avoid installing a low-quality part that'll fail in a few weeks/months.
But if you're someone who likes to be sure before swapping components, stick with me. In this tutorial, I'll walk you through exactly how to test the CMP sensor with a basic multimeter and find out whether it's really to blame for that P0340 code.
Where To Buy The CMP Sensor And Save
Camshaft Position Sensor Connector Pinout
| CMP Sensor Circuits | ||
|---|---|---|
| Terminal | Wire | Description |
| 1 | Pink with yellow stripe (PNK/YEL) | 5 Volts DC |
| 2 | Dark blue with dark green stripe (DK BLU/DK GRN) | Ground |
| 3 | Dark blue with gray stripe (DK BLU/GRY) | CMP Sensor Signal |
TEST 1: Checking The CMP Signal With A Multimeter
To kick things off, we'll check if the camshaft position (CMP) sensor is generating its expected ON/OFF voltage signal as you manually rotate the engine using a 1/2-inch ratchet and socket on the crankshaft pulley bolt.
Why turn it by hand? Because using the starter motor spins the engine way too fast —the multimeter won't be able to catch the rapid voltage changes the CMP sensor puts out.
By slowly turning the engine yourself, you'll be able to clearly see the signal toggling ON and OFF right on the meter.
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're lifting the front of the minivan for access to the crank bolt, always use jack stands. Never rely on the jack alone —safety first.
NOTE: Keep the CMP sensor connected during the test. You'll need to back probe the connector or use a wire-piercing probe to access the signal wire. You can see an example of this tool (and where to buy it) here: Wire Piercing Probe.
Here's how to run the test step-by-step:
- 1
Disconnect the ignition coil pack from its harness connector.
IMPORTANT: This ensures the engine doesn't accidentally start while you're turning it by hand. - 2
Set your multimeter to Volts DC mode.
- 3
Connect the black lead to the battery's negative (-) terminal.
- 4
Probe the DK BLU/GRY wire of the CMP sensor's connector using the red multimeter test lead.
You can either back probe the connector or pierce the wire with a wire piercing probe. - 5
Rotate the crankshaft pulley clockwise by hand while watching the multimeter.
IMPORTANT: Do not use the ignition key to crank the engine. The sensor signal must be checked manually at slow speed. - 6
You should see the voltage toggle between 5V and 0V.
When the signal is ON, you'll read about 5 Volts DC. When it's OFF, it'll drop to 0.3 to 0.5 Volts (which we treat as 0V for this test).
IMPORTANT: Turn the pulley through at least two full revolutions to capture the complete signal cycle.
Once you've got your readings, here's how to interpret them:
CASE 1: You saw a clear ON/OFF voltage pattern. That's exactly what you want to see. It confirms the CMP sensor is alive and sending a valid signal to the PCM.
This also tells you the sensor has both power and Ground —without either, there'd be no signal at all. So if you're dealing with code P0340 and you see this pattern, the CMP sensor likely isn't the root cause.
CASE 2: No ON/OFF signal detected. Double-check your connections and multimeter settings.
If there's still no signal, your next step is to find out whether the CMP sensor is getting power. Head over to: TEST 2: Making Sure The CMP Sensor Is Getting 5 Volts.