P3427 — Cylinder 4 Deactivation/Intake Valve Control Circuit Low

What does OBD2 code P3427 mean?

OBD2 code P3427 flags a problem with the sensor and actuator circuits (cylinder 4 deactivation/intake valve control circuit low). The car is usually drivable while you plan the repair. Common culprits: corroded, loose or damaged connector, open or shorted wiring in the circuit, control module driver fault.

What are the symptoms of P3427?

Drivers most often notice: possible limp mode depending on the affected component, the affected system operates intermittently or not at all, Check Engine Light on, increased fuel consumption in some cases.

Will P3427 clear itself?

Sometimes P3427 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How much does it cost to fix P3427?

Replace the faulty sensor or actuator — $150–$500; Control module repair — $300–$1,000; Repair wiring or connectors — $80–$250. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

What is the most common cause of P3427?

The most common causes are: corroded, loose or damaged connector, open or shorted wiring in the circuit, control module driver fault.

What does P3427 mean?

The engine control module sets P3427 when it detects a fault in the sensor and actuator circuits. In practical terms: cylinder 4 deactivation/intake valve control circuit low. The code belongs to the powertrain (engine/transmission) group of OBD2 codes.

P3427 refers specifically to cylinder 4. On inline engines cylinders are counted from the front (belt end); on V-engines the numbering depends on the manufacturer, so check the firing-order diagram for your exact model. Location matters for the repair bill: some cylinders require intake manifold removal, which adds labor time.

“Circuit low” means the voltage on the cylinder 4 deactivation/intake valve control circuit stays below the expected minimum — close to ground. The usual physical reasons are a short to ground, a chafed wire touching metal, a missing supply voltage, or a failed component dragging the signal down.

This code does not appear from a single bad reading: the module must see the fault condition repeat under defined operating conditions before it turns on the warning light. The freeze frame captured with P3427 — engine load, rpm, temperature, speed — tells you exactly when the problem occurs, so reproduce those conditions when testing.

Common symptoms of P3427

• possible limp mode depending on the affected component
• the affected system operates intermittently or not at all
• Check Engine Light on
• increased fuel consumption in some cases

What causes P3427?

• failed cylinder 4 deactivation/intake valve control pulling the signal low
• signal wire shorted to ground (chafed insulation)
• missing supply voltage to the cylinder 4 deactivation/intake valve control
• faulty sensor or actuator of the affected circuit
• poor ground connection
• control module driver fault
• open or shorted wiring in the circuit
• corroded, loose or damaged connector

How to diagnose P3427

1. Connect an OBD2 scanner, confirm P3427 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
2. Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
3. Visually inspect the wiring harness and connectors related to the cylinder 4 deactivation/intake valve control for damage, corrosion, chafing or poor contact.
4. Check for supply voltage at the cylinder 4 deactivation/intake valve control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
5. Measure reference voltage, ground and signal continuity at the component connector.
6. Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
7. Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P3427 does not return.

How to fix P3427

Start with the cheapest and most common causes before replacing expensive parts:

• Replace the faulty sensor or actuator — $150–$500
• Control module repair — $300–$1,000
• Repair wiring or connectors — $80–$250

How much does it cost to fix P3427?

Repair cost depends on which component actually failed. Typical scenarios for P3427 (parts and labor, USD, independent shop rates):

• Replace the faulty sensor or actuator: $150–$500
• Control module repair: $300–$1,000
• Repair wiring or connectors: $80–$250

Overall, fixing P3427 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Can you drive with P3427?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

Related OBD2 codes

• P3400: Cylinder Deactivation System Bank 1
• P3401: Cylinder 1 Deactivation/Intake Valve Control Circuit/Open
• P3402: Cylinder 1 Deactivation/Intake Valve Control Circuit Performance
• P3403: Cylinder 1 Deactivation/Intake Valve Control Circuit Low
• P3404: Cylinder 1 Deactivation/Intake Valve Control Circuit High
• P3405: Cylinder 1 Exhaust Valve Control Circuit/Open