P0344 Code: Camshaft Position Sensor A Circuit Intermittent (Bank 1)

What the P0344 code means

The camshaft position sensor reports the phase of the engine. Its signal has to be continuous and steady while the engine turns.

The P0344 code is stored when that signal cuts out for a moment and then returns. It is not missing the way it is on P0340, and it is not out of range the way it is on P0342. It comes and goes.

That turns the diagnosis into a different kind of job. Static measurements in the shop, with the engine off or idling cold, almost always read correctly, because the fault needs a specific condition to show itself.

The three conditions that cause it are almost always the same. Vibration, which momentarily opens a conductor broken inside its insulation or a backed-out pin. Heat, which expands a wire with a crack and breaks the contact. And harness movement, which happens when you hit a bump or accelerate against the engine mounts. Recreating those conditions on purpose is what lets you find the fault.

There is one technique that turns an intermittent fault into one you can repeat: recording data while you drive. Many scan tools can log parameters on the road, and when you review the recording you can see the exact instant the signal drops out along with the conditions at that moment. It is the most reliable way to locate a fault that never appears with the vehicle parked in the shop.

P0344 code symptoms

• Check engine light that comes and goes.
• Sudden stalling that clears up when you restart.
• Isolated hesitation when you accelerate or hit bumps.
• Starting that is normal some days and very long on others.
• The fault appears with the engine hot and disappears cold, or the other way around.
• The vehicle runs normally for days between episodes.
• The shop finds nothing because the fault is not present.
• The fault never reproduces with the vehicle parked in the shop.

Likely causes of the P0344 code

1. Conductor broken inside its insulation, which opens with vibration. The classic cause of this code.
2. Backed-out pin in the connector, with contact that is lost when the connector moves.
3. Insulation cracked by heat, which shorts only at a certain temperature.
4. Metal shavings stuck to the sensor tip.
5. Sensor with an intermittent internal fault, typically one that fails when hot.
6. Harness rubbing against a moving or hot part.
7. Moisture in the connector, with faults that depend on the weather.
8. Tone wheel with a damaged tooth, which causes periodic dropouts.

How to diagnose the P0344 code step by step

1. Look at the freeze frame data. With an intermittent fault, knowing the conditions when it was stored is the most valuable information you have.
2. Wiggle the harness with the engine running, section by section, while you watch the reading. This test finds more intermittent faults than any other.
3. Flex the wire near the connector and near the sensor, which are the places where wires break most.
4. Heat the area with a heat gun if the fault appears when hot, and see whether it reproduces.
5. Remove the sensor and clean its tip of shavings and oil.
6. Check the connector by gently tugging each wire to find backed-out pins.
7. Watch the signal with an oscilloscope during a road test, if your equipment allows it. It captures the dropout at the moment it happens.
8. Inspect the tone wheel for a damaged tooth.
9. Record parameters with the scan tool while driving and review the recording. It shows the exact instant of the dropout and the conditions when it happened.

How to fix the P0344 code

• Replace the section of wire with the broken conductor instead of splicing it, because the break tends to spread.
• Replace the terminals that have backed-out pins.
• Protect the harness with heat-resistant sleeving and secure it so it does not rub or move.
• Clean the sensor tip and its bore.
• Replace the sensor if it fails when you warm it with the heat gun.
• Dry the connector and protect it with dielectric grease.
• Correct the tone wheel if it has a damaged tooth.
• Use the on-the-road data recording to find the moment and the conditions of the dropout before you take anything apart.

With an intermittent fault, verification takes time. Drive for several days in the conditions where it used to appear before you call the job finished.

Technical reference data

• Hall effect sensors: 5 or 12 volt supply and a square wave signal.
• Inductive sensors: typical resistance of 200 to 1,500 ohms.
• Usual air gap: 0.5 to 1.5 millimeters (about 0.020 to 0.060 in).
• The freeze frame data shows the exact conditions when the dropout was stored.
• A conductor broken inside its insulation does not show up when you measure continuity at rest. You have to flex the wire.
• Recording parameters while driving captures the instant of the dropout and its conditions.

Brand-specific notes

An intermittent fault is not diagnosed with static measurements. The technique that works is to recreate the condition: move the harness, warm the area, flex the wire near both ends. Measuring continuity with the engine off will give a correct result that means nothing.

If the freeze frame data says the fault appeared with a hot engine, start there. Warm the sensor area and its wiring with a heat gun and see whether the signal drops out.

Frequently asked questions about P0344