P0340 Dodge Ram: Causes, Symptoms, and Fix by Engine 2026

If your scanner just flagged P0340 on your Dodge Ram, the fix you need depends entirely on which engine is under the hood.

P0340 is a camshaft position sensor circuit fault. But a 1999 Ram with a 5.9L Magnum and a 2018 Ram with a 5.7L Hemi solve it in completely different ways.

This guide splits the diagnosis by engine family, then handles the question that brings most owners here. Your sensor is already replaced and the code came back.

What the P0340 Code Means on a Dodge Ram

P0340 stands for Camshaft Position Sensor “A” Circuit malfunction. The Powertrain Control Module lost a usable signal from the cam sensor on Bank 1 or the single sensor.

The camshaft position sensor (CMP) tells the PCM how the camshaft is spinning and where it sits. The PCM uses that reading to time fuel injection and spark.

The PCM cross-checks the cam signal against the crankshaft position sensor. Think of it as two clocks that must agree. When they stop agreeing, or the cam clock goes silent, the PCM sets P0340.

That cross-check matters later. A bad crank signal or a stretched timing chain can throw the cam code even when the cam sensor itself is fine.

P0340 Symptoms Dodge Ram Owners Report

The most common complaint is a long crank. The starter spins for several seconds before the engine catches, then it runs fine once started.

One owner on a 2006 Ram 1500 5.7 Hemi described roughly an eight second crank every start with P0340 stored, yet normal driving afterward. That pattern is classic for a marginal cam signal.

Other reported symptoms include stalling while driving, rough idle, reduced power, and worse fuel economy. Some trucks drop into limp mode and refuse to shift past fourth gear.

In the worst cases the engine cranks but will not start at all. If that describes your truck, work through our guide on why a Dodge Ram cranks and has power but will not start alongside this code.

One distinction helps. A hard, constant P0340 points to a dead circuit. A flickering signal that comes and goes usually pairs with P0344, the intermittent version of the same fault.

First Identify Your Dodge Ram Engine

The right repair path is set by your engine, so start here.

• 5.2L and 5.9L Magnum, plus 3.9L V6 (through 2003): the cam signal comes from a pickup inside the distributor. There is no separate bolt-on cam sensor.
• 4.7L PowerTech and 5.7L Hemi (2002 onward): one external cam sensor sits on the front timing cover. No distributor.
• 3.6L Pentastar V6 (2013 onward): two cam sensors and variable valve timing.
• 6.7L Cummins Turbo Diesel: its own dedicated cam sensor on the gear housing, separate from the gas engines above.

The 5.7L Hemi arrived for the 2003 model year and replaced the 5.9L Magnum on the Ram 1500, 2500, and 3500. The 3.6L Pentastar replaced the 3.7L V6 as the base engine in 2013.

Find your engine above, then jump to the matching branch below.

7 Most Common Causes of P0340 on a Dodge Ram

Before you buy parts, know what actually triggers this code. These are ranked from most to least common based on Ram owner reports and dealer service bulletins.

Wiring sits higher on this list than most owners expect. In one widely cited Ram thread, the fix was a failing signal lead at the connector, not the sensor, and the new sensor only held once the wiring was repaired. You can read that Ram owner cam sensor wiring repair for the full sequence.

Fixing P0340 on a 5.2L or 5.9L Magnum Ram 1998 to 2003

If you have a Magnum V8 or the 3.9L V6, your cam signal lives inside the distributor. There is no separate sensor bolted to the block.

This trips up parts counters constantly. Owners are often told their truck “does not have a cam sensor,” which is wrong. The pickup plate inside the distributor does that job.

On these trucks P0340 often shows up next to P1391, an intermittent cam or crank signal code. Both point back to the distributor pickup or the wiring to it.

The repair is either a new distributor pickup or a remanufactured distributor. After fitting it, you must re-index the distributor so cam timing reference stays correct.

For the exact location and orientation on these trucks, see our walkthrough on the 2002 Ram 1500 5.9 camshaft position sensor location. A reman distributor costs more than a simple sensor, often into the low hundreds, so price it at a supplier like RockAuto before you buy.

Fixing P0340 on a 4.7L or 5.7L Hemi Ram 2002 to 2024

This is the most common case. The 4.7L and 5.7L Hemi use one external cam sensor and no distributor.

The sensor sits on the front of the engine, on the timing cover, passenger side, near the thermostat housing and above the lower radiator hose. It is usually a quick two bolt job.

Replace it in three steps.

1. Unplug the electrical connector at the sensor and check the pins for oil, corrosion, or a loose lead.
2. Remove the single hold down bolt and pull the old sensor straight out.
3. Seat the new sensor, torque the bolt lightly, reconnect the plug, then clear the code and test drive.

Use a Mopar or premium aftermarket sensor here. Ram owners repeatedly report that budget sensors re-throw the code within days, while OEM grade parts hold.

On the Hemi, P0340 frequently appears with P0344, the intermittent version. Chrysler also revised the diagnostic logic over the years so the PCM is less sensitive to brief signal dropouts, which is why a borderline sensor may set the code only sometimes.

For year specific placement and photos, our Dodge Ram 1500 camshaft position sensor location guide shows exactly where to reach. Check for oil weeping from the valve cover too, since a leak can foul the new sensor fast.

Fixing P0340 on a 3.6L Pentastar Ram 2013 to 2024

The 3.6L Pentastar V6 uses two camshaft position sensors and variable valve timing, so code mapping matters.

P0340 and P0344 point to Bank 1, the passenger side sensor. P0345 and P0349 point to Bank 2, the driver side sensor.

The Bank 1 sensor can sit where the upper intake must come off for clean access, which makes this job longer than the Hemi swap. Plan for extra time and a fresh intake gasket.

Oil contamination is common on this engine. Inspect the sensor and connector for seepage, and confirm the bank before you order, since the two sensors are not always the same part.

Why P0340 Came Back After You Replaced the Sensor

This is the situation that brings most searchers here. The sensor is new and the code returned, sometimes within a single drive.

Work through these in order.

1. The replacement sensor is the problem. Budget aftermarket sensors fail at a high rate on these trucks. If you used a no name part, fit a Mopar or premium sensor before going further.

2. The wiring or connector is damaged. Heat near the engine cracks the signal lead where it enters the plug. The fix is a pigtail repair or a new connector, not another sensor.

3. The crank sensor disagrees. The PCM compares cam and crank signals. A weak crank sensor or a correlation fault can keep the cam code alive, often shown by P0016 sitting alongside it.

4. A misfire appears with it. If P0300 shows up, treat the running fault as well. Our guide on the Dodge Ram 1500 P0300 misfire code covers that path.

5. Timing components are worn. On the Hemi VVT, a stretched timing chain or a failing cam phaser can shift the cam signal enough to set P0340. One owner reported a dealer replacing a cam phaser for around 1,700 dollars with the code still present afterward, so confirm the fault before approving that work.

The lesson is simple. Stop replacing the sensor once it has been done with a quality part. Move to wiring, then crank signal, then timing.

P0340 Repair Cost on a Dodge Ram

Costs swing widely because the same code covers a 15 dollar pickup and a timing job. Here are real ranges by repair.

Shop ranges above reflect RepairPal Ram 1500 camshaft sensor replacement estimates. Doing the Hemi sensor yourself drops it to the cost of the part plus 20 minutes.

P0340 Dodge Ram Quick Diagnostic Matrix

Use this to self route. Match your engine, then follow the primary fix and the thing to watch.

When to Stop DIY and See a Technician

Most P0340 cases are a do it yourself fix. A few are not, and chasing those as electrical faults wastes money.

Get a professional scan and inspection if the code stays after you have replaced a quality sensor, repaired the wiring, and tested the crank sensor.

Also stop if P0016 shows an abnormal cam and crank correlation, if you hear a timing area noise, or if the engine has zero compression on a cylinder. On these interference engines, a jumped timing chain can bend valves.

At that point the problem is mechanical, not a sensor, and it needs the front cover off to diagnose correctly.

Final Word on P0340

Match the fix to your engine before you spend a dollar. A Magnum needs a distributor pickup, a Hemi needs an external sensor, and a Pentastar needs the correct bank.

If the code returns, the answer is almost never another cheap sensor. It is the wiring, the crank signal, or worn timing.

Work the order in this guide and you will clear P0340 without throwing parts at the truck.

P0340 Dodge Ram FAQ

Can I drive my Dodge Ram with a P0340 code?

You can usually drive short distances, but it is risky. The truck may stall, start hard, lose power, or drop into limp mode, so fix it promptly.

Will a bad camshaft sensor keep my Ram from starting?

Yes. A failed cam signal can cause a long crank or a full crank and no start, because the PCM cannot time fuel and spark without it.

Does P0340 always mean the camshaft sensor is bad?

No. It means the cam signal circuit failed. The cause can be the sensor, the wiring or connector, the crank sensor, oil contamination, or worn timing components.

Why did P0340 come back after I replaced the sensor?

The usual reasons are a cheap aftermarket sensor, damaged signal wiring, a crank correlation fault, or a stretched timing chain on the Hemi VVT.

Is it the camshaft or crankshaft sensor causing P0340?

P0340 is specifically the camshaft circuit. A weak crank signal can still keep it alive through a correlation fault, which usually shows up as P0016 next to it.