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DTC codes / P34xx · Auxiliary emission controls / P3457

P3457Cylinder 8 Deactivation/lntake Valve Control Circuit/Open

P3457 is a generic powertrain code indicating that the powertrain control module (PCM) has detected an open circuit or abnormal voltage in the control circuit for the cylinder 8 deactivation/intake valve, which is part of a variable displacement or cylinder deactivation system. The PCM monitors the circuit and sets the code when the commanded state does not match the expected electrical feedback, often due to a wiring fault, failed solenoid, or mechanical issue.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaAuxiliary emission controls

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Rough idle or vibration when the engine transitions between full and reduced displacement modes
  • Reduced engine power or a stumble during light-throttle cruising
  • Audible ticking or tapping from the affected cylinder bank
  • Poor fuel economy if the cylinder deactivation system remains disabled
  • In rare cases, a misfire code may accompany P3457 if the valve remains stuck

Common causes, most likely first

  1. Open or damaged wiring in the cylinder 8 deactivation solenoid control circuit
  2. Failed cylinder 8 deactivation solenoid or intake valve control solenoid
  3. Corroded or loose electrical connector at the solenoid or PCM
  4. Faulty powertrain control module (PCM) driver circuit
  5. Mechanical binding or failure of the intake valve control mechanism
  6. Oil sludge or debris obstructing the solenoid or oil passages

How to diagnose and fix it

  1. Inspect the wiring harness and connector at the cylinder 8 deactivation solenoid for damage, corrosion, or looseness
  2. Measure resistance of the solenoid and compare to manufacturer specifications
  3. Check for battery voltage and ground signals at the solenoid connector with the key on and engine off
  4. Test the control circuit for continuity and shorts to ground or power using a digital multimeter
  5. If electrical checks pass, perform an active test of the solenoid with a scan tool to verify mechanical operation
  6. Inspect oil condition and passages for sludge if the solenoid is oil-controlled
  7. Replace the faulty solenoid or repair wiring as needed, then clear codes and verify the repair

Cylinder 8 Deactivation Circuit Quirks

  • A P3457 can be set by a simple loose connector that only acts up under vibration, so always wiggle-test the harness while monitoring live data.
  • The code may appear after an oil change if the wrong viscosity oil was used, causing the solenoid to respond sluggishly and set an open-circuit fault.
  • Some vehicles will not illuminate the check engine light for this code until the fault occurs on two consecutive drive cycles, so intermittent issues can be missed.
  • A failed solenoid can sometimes be temporarily freed by tapping it, but this is not a repair and the code will return.
  • The PCM may disable the entire cylinder deactivation system when this code is set, leading to a noticeable drop in fuel economy even if the engine runs smoothly.

Can I keep driving with P3457?

You can generally continue driving with P3457, but the vehicle may enter a reduced-power mode or disable cylinder deactivation, which can affect fuel economy and performance. Avoid heavy acceleration or towing until the fault is repaired, and address the issue promptly to prevent potential catalytic converter damage from unburned fuel.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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