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P3440 — Cylinder 5 Exhaust Valve Control Circuit High

Manufacturer-specificPowertrain (engine & transmission)

This code indicates that the engine computer has detected an abnormally high voltage in the electrical circuit controlling the exhaust valve for cylinder 5. This usually points to a short to power in the wiring, a failed exhaust valve control solenoid, or a poor electrical connection rather than a mechanical engine issue.

Symptoms

What causes it — most likely first

1. Failed Cylinder 5 Exhaust Valve Control Solenoid

The solenoid itself may have an internal short circuit, causing it to draw excessive voltage or send a high voltage signal back to the computer.

2. Shorted Wiring Harness

The wires leading to the cylinder 5 exhaust valve control solenoid may be chafed or melted, causing a short to voltage in the circuit.

3. Poor Electrical Connection

Corroded, pushed back, or loose pins in the solenoid or engine computer connectors can cause high resistance or false voltage readings.

4. Failed Exhaust Valve Rocker Arm

If the mechanical rocker arm that the solenoid controls is physically broken or seized, it can cause abnormal electrical feedback in the circuit.

5. Failed Engine Computer (PCM/ECM)

An internal failure in the engine computer driver circuit is extremely rare but can improperly send continuous voltage to the solenoid.

How it's diagnosed

  1. Clear the code and perform a road test to see if the P3440 code immediately returns.
  2. Inspect the wiring and connectors at the cylinder 5 exhaust valve control solenoid for signs of damage, chafing, or corrosion.
  3. Disconnect the solenoid and check for battery voltage at the control circuit with the ignition on to confirm the 'high' condition.
  4. Test the resistance of the cylinder 5 exhaust valve control solenoid and compare it to the manufacturer's specifications.
  5. Perform a mechanical inspection of the cylinder 5 exhaust valve rocker arm and camshaft to ensure they move freely.
  6. If all wiring, the solenoid, and mechanical components test normal, check the engine computer output and ground circuits.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)
Related codesP3438 — Cylinder 5 Exhaust Valve Control CircuP3439 — Cylinder 5 Exhaust Valve Control CircuP3441 — Cylinder 6 Deactivationintake Valve CoP3442 — Cylinder 6 Deactivationintake Valve CoP3443 — Cylinder 6 Deactivationintake Valve CoP3444 — Cylinder 6 Deactivationintake Valve Co

Frequently asked

Does P3440 mean my engine computer (PCM/ECM) is bad?

No, it almost never does. Drivers are frequently told to replace the PCM for this code, but a high circuit voltage is overwhelmingly caused by a shorted wire, a failed solenoid, or a bad connection. The PCM is the least likely cause and should only be considered after all wiring and solenoids are thoroughly tested.

Can I still drive my car with this code?

It is not recommended. The engine may run poorly, misfire, or lose power. Continuing to drive with a malfunctioning valve control system can potentially cause internal engine damage or clog the catalytic converter.

Is this a mechanical engine problem or an electrical one?

The code specifically refers to an electrical circuit fault ('Circuit High'), meaning the problem is likely electrical. However, a mechanical failure of the valve rocker arm can trigger this code, so both the electrical solenoid circuit and the mechanical valve train should be inspected.

How is the exhaust valve control solenoid tested?

The solenoid is typically tested by checking its internal electrical resistance with a multimeter and applying power and ground to see if it actuates properly. It must be disconnected from the harness to isolate it from the vehicle wiring during testing.