OBD-II Code
P3406
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$40–$4,500
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P3406 means the ECM commanded cylinder 2 to deactivate (collapse the intake lifter, hold the valve closed) and the performance feedback didn't match — same diagnostic flow as P3401 but on cylinder 2.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP3406 means the ECM commanded cylinder 2 to deactivate (collapse the intake lifter, hold the valve closed) and the performance feedback didn't match…
P3406 means the ECM commanded cylinder 2 to deactivate (collapse the intake lifter, hold the valve closed) and the performance feedback didn't match — same diagnostic flow as P3401 but on cylinder 2.
Cheapest-first ladder
- ohm the cylinder-2 MDS/AFM solenoid across the two harness pins (8 to 15 ohms cold = healthy) and confirm the ECM commands a 0.5 to 1.5A current pulse during the deactivation event.
- Scan oil pressure at the deactivation gallery — sub-25 psi at idle or sub-45 psi at 2000 rpm means worn oil pump or clogged AFM/MDS oil-pressure-control valve, and the lifter never gets the hydraulic pressure it needs to collapse.
- Watch the cylinder-2 misfire counter during a commanded deactivation cycle — a healthy deactivation reads zero contribution (cylinder runs as a closed-valve spring), any misfire count means partial lifter collapse or failed reactivation.
- On a transverse Honda J35, cylinder 2 is on the rear bank closest to the firewall; on a Chrysler Hemi, cylinder 2 is on the passenger side front; on a GM LS-based V8, cylinder 2 is on the passenger side front as well — verify the firing order and bank layout before pulling the wrong solenoid.
- The expensive misdiagnosis: Chrysler 5.7/6.4 Hemi MDS lifters are the actual problem on 80% of P3400-P3424 codes — a collapsed cylinder-2 lifter loses valve actuation entirely and mimics every symptom of a failed solenoid, and replacing the solenoid on a failed-lifter engine clears the code for 50-200 miles then returns it.
Vehicle-specific patternsChrysler 5.7L Hemi (RAM 1500 2009-current, Charger/Challenger R/T 2005-current, Grand Cherokee, Durango, 300C) throws P3406 on cylinder 2 in the same…
Chrysler 5.7L Hemi (RAM 1500 2009-current, Charger/Challenger R/T 2005-current, Grand Cherokee, Durango, 300C) throws P3406 on cylinder 2 in the same lifter-collapse pattern as the rest of the MDS family — the Hemi tick noise from a collapsed lifter is audible at idle through a stethoscope on the valve cover before the code even sets, and any P3406 on a 100k+ mile Hemi should start there. 6.4L Hemi SRT (392 Charger/Challenger, Grand Cherokee SRT, Durango SRT) shares the failure mode at accelerated wear rates. GM AFM 5.3L L83 (Silverado/Tahoe/Suburban 2014+), 6.0L (Avalanche/Yukon XL), and 6.2L L86/L87 (Silverado/Sierra/Tahoe/Yukon 2014+) sees the same cylinder-2 lifter collapse plus AFM oil-pressure-relief-valve failure that drops gallery pressure below activation spec; AFM-delete kits run $1,800-$3,200 installed. Ford 5.0L Coyote VCT-i (Mustang GT, F150) doesn't set true MDS codes but throws cylinder-specific VCT performance codes when oil sludge clogs the phaser oil control valve screens. Honda VCM J35 V6 (Pilot, Odyssey, Ridgeline, Accord V6) cylinder 2 sits on the rear bank and is part of the three-cylinder deactivation group; chronic VCM misfires here are the textbook 80K-150K mi failure that motivates the $120 VCM disable harness. Hemi lifter + roller cam rebuild runs $2,500-$4,500 parts + 12-16 hr labor.
Estimated repair$40 to $4,500.
Look up another code
More free tools