P3490: Cylinder Deactivation System Performance Bank 1
The engine control module has detected that the cylinder deactivation system on bank 1 is not performing as expected. Closed-loop monitoring of pressure response, valve timing or misfire counters during transitions indicates the system fails to deactivate or reactivate cylinders within calibrated limits.
What P3490 means
P3490 is a generic OBD-II powertrain code in the timing, cam & crank group. In plain English: the signal is within electrical limits but doesn’t make sense compared with other readings, so the part or system isn’t performing as expected. Bank 1 is the side of the engine with cylinder 1 (inline engines only have bank 1).
- Check engine light
- Usually on
- Emissions-related
- Yes — can fail inspection
- Limp mode possible
- Not typical
- Drive cycle to clear
- Required
Get it fixed
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Common causes
- 01Switching lifter stuck or wornMost likely
- 02Insufficient oil pressurePossible
- 03Solenoid slow or contaminatedPossible
Can I drive with P3490?
Usually yes, for a short time.
The car will often drive normally, but get it diagnosed soon. Left alone it can raise fuel use and emissions and will fail an OBD inspection. If you notice rough running, warning lights flashing, overheating or a burning smell, stop driving.
Why we rate it moderate
- Turns on the check engine light
- Emissions-related: will usually fail an OBD inspection
- Needs a drive cycle to confirm a repair
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose P3490
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just P3490. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Check for related codes first
Look for P3491. Related codes often share a cause; a circuit or sensor code usually needs fixing before a performance code like this one.
- 3
Check live data
Watch the related sensor and actuator readings in live data (Cylinder deactivation solenoid, Lifter, Oil control valve) and compare them with expected values in the service information for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Switching lifter stuck or worn; insufficient oil pressure; solenoid slow or contaminated. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and complete a full drive cycle (cold start, idle, steady highway cruise, deceleration). The code is fixed when the related readiness monitor completes without it returning.
P3490 repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Shop only
- Good DIY job?
- Usually a shop job
Needs dealer-level tools or high-voltage training.
Parts and systems involved
- Cylinder deactivation solenoid
- Lifter
- Oil control valve
P3490 FAQ
What does P3490 mean?
P3490 means “Cylinder Deactivation System Performance Bank 1”. The engine control module has detected that the cylinder deactivation system on bank 1 is not performing as expected. Closed-loop monitoring of pressure response, valve timing or misfire counters during transitions indicates the system fails to deactivate or reactivate cylinders within calibrated limits.
Is P3490 serious? Can I keep driving?
We rate P3490 as moderate severity. Usually yes, for a short time. The car will often drive normally, but get it diagnosed soon. Left alone it can raise fuel use and emissions and will fail an OBD inspection. If you notice rough running, warning lights flashing, overheating or a burning smell, stop driving.
What causes P3490?
The most common causes, from most to least likely: Switching lifter stuck or worn; Insufficient oil pressure; Solenoid slow or contaminated. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix P3490?
Typical labor is about $375–$1,500 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix P3490 myself?
DIY difficulty is shop only. Most owners leave this to a shop because it needs involved testing or specialist tools. Always confirm the cause before buying parts.
Will P3490 clear itself?
Once the fault is fixed, the check engine light usually goes off by itself after the system passes its self-test over several drive cycles. Clearing the code with a scan tool resets readiness monitors, so an inspection station may turn you away until a full drive cycle is completed.