OBD-II trouble code
P0349: Camshaft Position Sensor 'A' Circuit Intermittent (Bank 2)
The Bank 2 'A' camshaft signal drops out briefly and then comes back. Nothing is wrong when you go to test it, so this one is diagnosed with recorded data during a drive rather than with a meter in the driveway.
Quick facts
- System
- Powertrain
- Category
- Camshaft / Timing
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $80 – $500
- DIY difficulty
- Advanced DIY
What does P0349 mean?
P0349 does not describe a broken circuit. It describes a circuit that works, stops working for a fraction of a second, and works again — and that difference changes the entire approach. Every static test you can perform in a parking lot is being run at the one moment the fault is not present, which is why people replace the sensor, see the light stay off for a week, and then have the code return.
What makes the signal come and go is almost always mechanical rather than electrical: a terminal that has lost its spring tension and separates when the engine rocks on its mounts, a wire with one strand left inside intact insulation, or a connector whose seal has hardened and lets the joint move with heat expansion. These faults are governed by vibration and temperature, so the useful question is not what is broken but when it breaks — over a specific bump, above a certain RPM, only after twenty minutes of highway driving, only on the first cold morning of the week.
That also makes P0349 the member of this family you can never declare fixed by clearing the code and driving for an afternoon. An intermittent that appears once a week looks identical to a repaired car for six days. Say so plainly if you are handing the vehicle back to someone: the honest answer is that confidence comes from reproducing the fault before the repair and then failing to reproduce it afterward under the same conditions, not from a quiet dashboard. There is also a safety dimension worth naming, because on engines that need cam sync to keep running, an intermittent dropout shows up as a stall in traffic with no warning and no other codes stored.
Common causes
- Terminal in the sensor connector that has lost tension and separates under vibration
- A wire broken inside intact insulation, making and losing contact as the engine rocks
- Hardened or missing connector seal letting moisture in only in certain conditions
- Sensor with a marginal internal joint that opens once it heat-soaks
- Harness routed so it rubs a moving component only at particular engine loads
- Loose or corroded engine-to-body ground shared by the sensor circuit
- Small amounts of metal debris on the sensor tip that shift position with vibration
Symptoms
- Check engine light that comes on, then goes out again on its own days later
- A brief stumble or momentary loss of power that clears itself
- Random stalling with no other codes stored, most often at low speed or idle
- Occasional long crank on one start out of many, then normal starts for weeks
- Symptoms that track with rough roads, hot weather, or heat soak after a stop
- No repeatable pattern the driver can describe, which is itself a useful clue
Diagnostic steps
- 1.Do not clear the code before recording freeze frame data. Engine temperature, load and RPM at the moment it set are the most valuable evidence you will get, and clearing destroys it.
- 2.Set up a scan tool to log the camshaft signal, RPM and sync status, then drive the vehicle under the conditions the freeze frame captured rather than idling in a bay.
- 3.With the engine running, wiggle-test the sensor connector and the harness section that follows the engine's motion while watching live data for a dropout.
- 4.Flex the harness against its normal direction of movement, not just side to side. A wire broken inside its insulation often only opens along one axis.
- 5.Check terminal tension in the connector with a matching pin rather than by eye — a spread terminal looks perfectly normal seated in the housing.
- 6.Warm the suspected connector and wire section with a heat gun while monitoring the signal, and cool it with freeze spray, to try to reproduce a temperature-driven dropout.
- 7.Confirm the engine-to-body ground straps are tight and corrosion free before condemning the sensor circuit.
- 8.After repairing, reproduce the original conditions deliberately before returning the vehicle. A clean drive under a different set of conditions proves nothing.
Repair cost
$80 – $500
Diagnosis is the bulk of the bill here rather than parts. Expect one to two hours of paid diagnostic time because the fault must be captured before it can be fixed. Terminal or connector repair is often $80 to $250; a sensor replacement adds $40 to $200 in parts plus its labor. Budget on the higher side if the fault only appears on the road.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with wiring harness / circuit repair preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an advanced DIY job. It typically requires specialty tools, scan-tool access, lifting equipment, or careful sequencing to avoid causing new failures. Plan for extended downtime and have a backup vehicle. Most owners are better served by a shop that has done this repair before.