Although a scan tool is a must-have tool, you don't need one to diagnose the camshaft position (CMP) sensor on the 1996-1997 5.2L/5.9L Dodge Ram 1500/2500 pickup.
With 3 simple tests, that are done with a multimeter, you can find out if the CMP sensor is bad or not and I'll show you how in this tutorial.
I'm also going to show you where you can buy the camshaft position sensor and save a few bucks.
NOTE: The camshaft position sensor is also known as the distributor pickup coil.
Contents of this tutorial:
- Symptoms Of A Bad Camshaft Position (CMP) Sensor.
- What The CMP Sensor Does.
- Circuit Descriptions Of The Camshaft Position Sensor.
- Where To Buy The Camshaft Position Sensor.
- TEST 1: Testing The Camshaft Position Signal.
- TEST 2: Making Sure The CMP Sensor Has 5 Volts.
- TEST 3: Making Sure The CMP Sensor Has Ground.
- More 5.2L, 5.9L V8 Dodge Ram Pickup Diagnostic Tutorials.
APPLIES TO: This tutorial applies to the following vehicles since they use the exact same camshaft position (CMP) sensor:
- Dodge Ram 1500 Pickup 5.2L V8: 1996, 1997.
- Dodge Ram 2500 Pickup 5.2L V8: 1996, 1997.
- Dodge Ram 1500 Pickup 5.9L V8: 1996, 1997.
- Dodge Ram 2500 Pickup 5.9L V8: 1996, 1997.
- Dodge Ram 3500 Pickup 5.9L V8: 1996, 1997.
WIRING DIAGRAM: You can find the ignition system wiring diagram here:
OTHER CMP SENSOR TESTS:
- How To Test The Distributor Pickup Coil (1989-1991 5.2L, 5.9L V8 Dodge Ram Pickup).
- How To Test The Camshaft Position Sensor (1992-1995 5.2L, 5.9L V8 Dodge Ram Pickup).
- How To Test The Camshaft Position Sensor (1998-2003 5.2L, 5.9L V8 Dodge Ram Pickup).
Symptoms Of A Bad Camshaft Position (CMP) Sensor
As you're probably already aware, the engine needs fuel and spark to start. The fuel injection computer uses the signals that the camshaft position (CMP) sensor and the crankshaft position (CKP) sensor create to start activating the fuel injectors and the ignition coil.
The fuel injection computer monitors the CMP signal as soon as the engine starts to crank. So when this signal is missing, it'll usually set a camshaft position sensor diagnostic trouble code:
- P0340: No Camshaft Signal At PCM.
- P1391: Intermittent Loss of CMP or CKP Signal.
These are some of the most frequent signs of a failing distributor pick-up coil:
- Engine no-start: The starter cranks the engine, but it won't start because the injectors aren't pulsing. The PCM doesn't have the correct signal to time fuel delivery. In some cases, spark may still be present, but the fuel side is out of sync.
- Random engine shut-offs: The engine might run normally, then suddenly shut off without warning —especially at idle or during low-speed driving.
- Check Engine Light (CEL): When the PCM detects missing or inconsistent CMP signals, it may trigger the check engine light. Diagnostic trouble codes (like Code P0340 or P1391) may point to a loss of the CMP sensor signal.
- Misfires or unstable idle: If the signal from the sensor is weak or glitchy, it can throw off fuel and spark timing. This leads to a rough idle, misfires, or jerky performance under load.
- Hard to start (hot or cold): A degraded sensor might still send occasional pulses, which is just enough to eventually start the engine —but it may take several long cranks before it catches.
- Sluggish throttle response: When fuel injection isn't correctly timed, acceleration can feel slow or uneven, especially when trying to speed up quickly.
What The CMP Sensor Does
On 1996-1997 V8 Dodge Ram pickups, the camshaft position sensor (CMP) is located inside the distributor. This sensor used to be called the distributor pick-up coil. Although the name changed, its function remains essential —it helps the PCM (engine computer) control fuel injection timing.
Here's what the CMP sensor does:
- Provides the Fuel Sync Signal:
- As the engine spins, the CMP sensor sends a digital signal known as the fuel sync signal to the PCM.
- This signal identifies which cylinder is currently on its compression stroke.
- Without it, the PCM can't time the fuel injectors correctly.
- Works alongside the Crankshaft Position Sensor (CKP):
- The engine also uses a crankshaft sensor mounted near the flywheel to track RPM and crank angle.
- However, the CKP signal alone doesn't tell the PCM which stroke each cylinder is on.
- The CMP signal fills in that missing detail, acting like a reference point for the PCM to identify the proper cylinder order.
- Helps time fuel injector operation:
- With accurate CMP input, the PCM can fire each injector at the right time during the engine's cycle.
- If the CMP signal is missing or incorrect, fuel delivery becomes erratic — or stops entirely.
- Assists with spark control (indirectly):
- While the crank sensor handles primary spark timing, the CMP signal helps the PCM confirm which cylinder is next in line.
Circuit Descriptions Of The Camshaft Position Sensor
The camshaft position sensor needs power and Ground to activate and produce its signal. As such, it has 3 wires coming out of its electrical connector.
In the table below, you'll find a short description of each of the 3 wires:
| 1996-1997 Camshaft Position Sensor Connector | ||
|---|---|---|
| Pin | Wire Color | Description |
| 1 | Violet with white stripe (VIO/WHT) | 5 Volts DC |
| 2 | Black with light blue stripe (BLK/LT BLU) | Sensor Ground |
| 3 | Tan with yellow stripe (TAN/YEL) | CMP Signal |
The following ignition system wiring diagram will further help you identify the camshaft position sensor circuits:
When testing the CMP sensor, it's important to know that it creates an ON/OFF voltage signal as the engine turns. ON is when the CMP signal is at 5 Volts DC. OFF is when the CMP signal is at 0 Volts.
The cool thing is that we can see this ON/OFF voltage switching between 5 Volts and 0 Volts with a multimeter, and this is how we're gonna' test it.
Where To Buy The Camshaft Position Sensor
The following links will help you comparison shop for the camshaft position sensor (distributor pick-up coil). I think you'll save a few bucks:
TEST 1: Testing The Camshaft Position Signal
Generally, when the camshaft position sensor fails, it'll usually stay stuck producing a single voltage value as the engine turns.
For our first test, we'll connect a multimeter to the CMP signal wire and check to see if the sensor's signal voltage is switching between 5 Volts and 0 Volts.
If the CMP signal does not switch ON and OFF, as the engine is turning, then the next step is to make sure that it's getting power (in TEST 2).
The wire that we need to test for the signal, is the tan with yellow stripe (TAN/YEL) wire.
IMPORTANT: The camshaft position sensor must be connected to its engine harness connector for this test to work. You'll need to use a back probe or a wire piercing probe to read the CMP voltage signal within the wire. You can see an example of a wire piercing probe here: Wire Piercing Probe.
NOTE: Don't have a multimeter or need to upgrade yours? Check out my recommendation: Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (at: amazon.com).
These are the test steps:
- 1
Disconnect the ignition coil from its electrical connector. This is an important safety precaution!
NOTE: Don't remove the distributor cap from the distributor. The distributor cap must be in place to hold down the camshaft position sensor. - 2
Connect the black multimeter test lead directly on the battery negative (-) terminal.
- 3
Place your multimeter in Volts DC mode.
- 4
With the red multimeter test lead, probe the tan with yellow stripe (TAN/YEL) wire of the cam sensor connector.
NOTE: The camshaft position sensor must remain connected to its engine wiring harness connector to be able to read its signal. - 5
Have your helper crank the engine for a few seconds once the multimeter test lead connections are set up.
- 6
Your multimeter should see the voltage switch between 5 Volts and 0 Volts DC as the engine is cranking.
Let's examine your CMP signal test result:
CASE 1: The ON/OFF voltage signal is present. This is the correct and expected test result.
This test result tells you that the CMP sensor is good and that it IS NOT behind the no-start problem you're diagnosing.
CASE 2: The multimeter DID NOT read the indicated ON/OFF DC voltage. This test result usually means that the camshaft position sensor is defective.
Before you replace it, make sure it's getting power and Ground. For the next test go to: TEST 2: Making Sure The CMP Sensor Has 5 Volts.