OBD-II Diagnostic Trouble Code
P0344 — Camshaft Position Sensor A Intermittent (Bank 1)
P0344 means the bank 1 camshaft position sensor A signal is dropping out intermittently. The ECM sees a signal most of the time but loses pulses or the whole signal for short periods.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
Camshaft Position Sensor A Intermittent (Bank 1)
Code
P0344
Category
Powertrain
Subsystem
Ignition
Truck-relevant
Yes
What this means for truckers
P0344 (Camshaft Position Sensor A Intermittent, Bank 1) — the cam sensor signal is flickering on and off. Usually an intermittent connector or chafed wire. Tap the cam sensor connector with a screwdriver handle while engine runs — if the engine stumbles, you've found a loose connector. Replacement: $80-300.
Before you replace parts — try this first
P0344 on the Ignition system is most often loose, corroded or backed-out connector pins at the cam sensor — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Random stalling, stumbles or hesitation, sometimes followed by a hard restart. Faults often show up hot or on rough roads. Between events the truck may run normally with only a check-engine light.
Common causes
- CommonLoose, corroded or backed-out connector pins at the cam sensor ($80–$300)
- CommonHarness chafing that shorts or opens with vibration ($100–$500)
- CommonCamshaft sensor failing when hot ($120–$450)
- OccasionalMetal debris on the sensor tip or a damaged target wheel ($150–$1500)
How to fix
Wiggle-test the harness and connector while watching the cam signal or sync status live
When to use: First step
Clean and re-pin or replace the connector, and secure the harness away from wear points
When to use: When wiggling causes dropouts
Replace the cam sensor and inspect the tip and target wheel
When to use: When the fault shows up hot with good wiring
Scope the cam signal during a road test to catch dropouts
When to use: When the fault cannot be reproduced in the shop
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P0300 — Random/Multiple Cylinder Misfire Detected
- → P0301 — Cylinder 1 Misfire Detected
- → P0302 — Cylinder 2 Misfire Detected
- → P0303 — Cylinder 3 Misfire Detected
- → P0304 — Cylinder 4 Misfire Detected
Frequently Asked Questions
Can I drive with code P0344?
P0344 is severity 3 — plan service within a few days. Performance is likely degraded already (you may feel reduced power, harsher shifts, or slightly worse fuel economy). Continuing to drive risks additional damage to adjacent components.
How much does it cost to fix P0344 on a commercial truck?
Total repair cost ranges $80–$1500 depending on the root cause. The cheapest fix is usually the first one listed below — Loose, corroded or backed-out connector pins at the cam sensor — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P0344 fail a DOT inspection?
P0344 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between P0344 and related codes?
P0344 is closely related to: P0300 (Random/Multiple Cylinder Misfire Detected), P0301 (Cylinder 1 Misfire Detected), P0302 (Cylinder 2 Misfire Detected), P0303 (Cylinder 3 Misfire Detected). These codes share the same subsystem (ignition) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P0344 is set without the companions, the issue is more isolated.
How do I prevent P0344 from coming back after a repair?
For P0344 (Camshaft Position Sensor A Intermittent (Bank 1)), prevention centers on the ignition system. Use OEM-spec injectors and spark plugs (gas). Address fuel quality issues immediately — bad fuel kills injectors. Cylinder balance test annually for early warning.