P349C

Code

Generic P — Powertrain

Cylinder 5 Deactivation/Intake Valve Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 20 EN: 35 RU: 20

AI status

Completed

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Page language: EN

Causes

Faulty cylinder deactivation solenoid/valve (oil control valve)
Wiring harness damage, connector corrosion or poor ground to solenoid
Blocked or restricted oil passage (dirty oil, sludge)
Failed hydraulic lifter, deactivator piston, or cam phaser
Low engine oil level or incorrect oil viscosity
Faulty camshaft position sensor or crankshaft position sensor

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Rough idle or vibration, especially at idle
Misfire indication or misfire count stored for cylinder 5
Reduced engine power or hesitation
Increased fuel consumption
Unusual valvetrain noise (tapping, rattle) from cylinder 5 area

What to check

Read DTC(s) and freeze-frame data with a capable scan tool; note related codes and misfire counts
Check engine oil level, condition and correct viscosity
Inspect wiring and connectors at the cylinder 5 deactivation solenoid and camshaft sensors for damage/corrosion
Monitor live data: commanded solenoid duty, solenoid voltage, camshaft position signals, and misfire counters
Measure solenoid resistance and compare to specification
Perform a power/ground presence check at the solenoid while commanding ON/OFF

Signal parameters

Solenoid supply voltage: ~11–14 V (battery voltage when circuit powered)
Solenoid coil resistance: typically low ohms (check OEM spec; common range 10–40 Ω)
Command duty cycle or PWM (0–100%) from ECU when modulating deactivation valve
Solenoid current draw while energized (often 0.1–2 A depending on design)
Camshaft position sensor waveform and relative timing (degrees CRank vs CAM)
Cylinder 5 misfire count and short/long-term fuel trim for that bank

Diagnostic algorithm

Verify the code: clear DTC(s) and perform an engine run to see if code returns and capture freeze-frame/live data.
Check oil: confirm correct level and condition; change oil/filter if extremely dirty or out of spec.
Visual inspection: check harness and connector at the cylinder 5 deactivation solenoid and related cam/valve components for corrosion, bent pins or damage.
Electrical test: with connector disconnected, measure solenoid coil resistance. With key on and engine off, verify ignition-switched power and ground presence. Backprobe and command the solenoid with a scan tool to verify voltage/duty and actuator response.
Actuator operation: command the deactivation solenoid on/off while listening for mechanical change. Use a small pressure gauge or mechanical inspection where applicable.
Sensor correlation: compare camshaft position sensor signals vs crankshaft to confirm expected timing and that the ECU sees valve change when commanded.
Oil control and passages: if solenoid and wiring OK, inspect/clean or replace oil control valve and check for blocked oil passages to the deactivation mechanism.
Mechanical inspection: if hydraulic and electrical checks pass, inspect lifter/deactivator, cam phaser and valvetrain for mechanical failure; perform compression or leak-down test on cylinder 5.
Replace components: replace the faulty solenoid, oil control valve, deactivator, or cam phaser as indicated. If wiring or connectors are damaged, repair or replace harness.
Verify repair: clear codes, perform functional test and a road test while monitoring live data to ensure the fault does not return.

Likely causes

Faulty or intermittently working oil control valve / deactivation solenoid on cylinder 5
Contaminated/low oil causing deactivation mechanism to stick
Open/short or poor connector at the solenoid harness
Failed deactivator or lifter on cylinder 5
Camshaft position sensor giving incorrect feedback

Fault status

⚠️ Status

DTC P349C stored — Cylinder 5 Deactivation / Intake Valve Performance fault detected. Possible deactivation solenoid, oil supply, wiring, sensor, or mechanical valvetrain issue. Further diagnosis required.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-4.0 hours