P0344
Camshaft Position Sensor A Circuit Intermittent (Bank 1)P0344 is a generic OBD-II powertrain diagnostic trouble code: Camshaft Position Sensor A Circuit Intermittent (Bank 1). It is logged by the engine control unit when the ckp/cmp monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0344 means
P0344 is stored when the PCM detects an intermittent or erratic signal from Camshaft Position Sensor "A" on Bank 1 (the bank containing cylinder #1) or on a single-cam engine. The CMP sensor reports the camshaft's rotational position so the PCM can determine which cylinder is approaching its compression stroke — critical for sequential fuel injection and variable valve timing control. Unlike a continuous CMP failure, P0344 indicates the signal is present most of the time but drops out unpredictably.
The intermittent nature creates characteristic driveability complaints: extended crank times (especially when the engine is hot, since the PCM must re-establish cam-crank sync after restart), momentary stalls at idle, and misfires that appear and disappear without a clear pattern. Hot-start difficulty is particularly telling because thermal expansion changes harness routing and connector tension, making borderline connections fail. Cam-tone ring damage is another specific cause — a cracked or missing segment on the tone ring creates a repeating missing-pulse signature that is best visualised on an oscilloscope. Variable valve timing systems are more sensitive to P0344 because VVT actuation relies on accurate cam-position feedback throughout the RPM range.
Common causes
Most-frequently reported root causes when P0344 is logged.
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1
Faulty camshaft position sensor with degraded Hall-effect element that intermittently drops out
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2
Damaged or cracked cam tone ring with missing or chipped segments
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3
Loose, corroded, or oil-contaminated sensor connector causing intermittent signal loss
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4
Chafed or heat-cracked wiring harness between sensor and PCM
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5
Timing chain stretch or timing component wear affecting cam-crank phase relationship
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6
PCM firmware fault or failed input circuit intermittently rejecting a valid signal
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7
Low engine oil pressure starving a variable valve timing (VVT) actuator, indirectly disrupting cam position
Symptoms drivers notice
How to diagnose P0344
A typical diagnostic flow when this code is present.
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1
Connect a scan tool and review freeze-frame data; note engine temperature at fault occurrence to identify a hot-start pattern
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2
Check live CMP sensor data at idle and under load for dropouts; compare cam and crank sensor signals to detect sync loss events
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3
Inspect the camshaft position sensor connector for corrosion, oil contamination, and secure pin retention — reseat the connector and clear codes to see if intermittent fault returns
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4
Visually or borescope-inspect the cam tone ring through the sensor port for cracks, chips, or missing segments
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5
Connect an oscilloscope to the CMP signal wire and perform a wiggle test on the harness while idling — any signal interruption during harness movement confirms a wiring fault
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6
Check timing chain slack or timing belt condition if the vehicle has high mileage; a stretched chain can introduce cam phasing variation that confuses the PCM
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7
Replace the sensor if all wiring and mechanical checks pass and the fault persists; clear codes and verify with a warm restart cycle
Related powertrain codes
- P000A — A Camshaft Position Slow Response Bank 1
- P000B — B Camshaft Position Slow Response Bank 1
- P000C — A Camshaft Position Slow Response Bank 2
- P000D — B Camshaft Position Slow Response Bank 2
- P0010 — A Camshaft Position Actuator Circuit (Bank 1)
- P0011 — A Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)
Frequently asked questions
Why does P0344 often appear during hot starts specifically?
Thermal expansion affects connector tension and harness routing near the sensor. A marginal connection that holds when cold can open fractionally when metal expands at operating temperature. Oil viscosity also drops when hot, sometimes allowing slight cam-phaser movement that destabilises the signal on VVT-equipped engines.
Can P0344 cause a no-start?
A brief dropout during cranking can make the engine crank longer than usual but the PCM will typically synchronise and start. A sustained CMP failure during cranking can prevent the engine from starting if the PCM cannot establish cam-crank sync, though this is more common with P0340 (continuous loss) than P0344.
Is P0344 related to variable valve timing problems?
It can be. If the VVT actuator is sticking or the cam phaser is worn, the camshaft position may fluctuate erratically, producing an intermittent signal variation that the PCM logs as P0344. Check engine oil level and pressure, as VVT systems are oil-pressure driven.
How do I distinguish a bad sensor from a bad tone ring?
An oscilloscope waveform is the clearest method. A bad sensor typically produces random dropouts or amplitude variation at any point in the waveform. A damaged tone ring produces a repeating missing or distorted pulse at the same crankshaft angle every revolution, which is visible as a consistent gap in an otherwise clean waveform.
Disabling P0344 in software
RaceTune can permanently disable P0344 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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