What Does P3440 Mean?
The ECM has detected an abnormally high voltage in the cylinder 5 exhaust valve control solenoid circuit. The voltage on the solenoid control line exceeds the expected threshold when the solenoid is not being commanded. This prevents the ECM from properly managing cylinder 5 exhaust valve deactivation and disables the cylinder deactivation system.
Common Causes
35%
Short to battery voltage in the cylinder 5 exhaust valve solenoid wiring
30%
Failed cylinder 5 exhaust valve solenoid with internal short to power supply
20%
ECM high-side driver failure outputting uncontrolled voltage
15%
Crossed or miswired pins at the VLOM connector contacting an adjacent B+ circuit
Diagnostic Steps
1
Step 1: With KOEO, backprobe the cylinder 5 exhaust valve solenoid control wire. Voltage should be near 0V when not commanded. A reading above 5V confirms the high circuit fault.
2
Step 2: Disconnect the solenoid and recheck voltage on the harness side. Voltage dropping to normal indicates a solenoid fault; persistent high voltage indicates a wiring fault.
3
Step 3: Inspect the wiring harness for contact with other power supply wires, especially near the fuse box and ignition relay outputs.
4
Step 4: Measure solenoid resistance (expect 5-12 ohms) and check from each terminal to the solenoid housing for internal shorts.
5
Step 5: Command the solenoid via scan tool bi-directional controls while monitoring the circuit with a DVOM. If the ECM cannot pull the circuit low, the driver may be damaged.
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The ECM has detected an abnormally high voltage in the cylinder 5 exhaust valve control solenoid circuit. The voltage on the solenoid control line exceeds the expected threshold when the solenoid is not being commanded. This prevents the ECM from properly managing cylinder 5 exhaust valve deactivati...
The most common cause of P3440 (Cylinder 5 Exhaust Valve Control Circuit High) is: Short to battery voltage in the cylinder 5 exhaust valve solenoid wiring
Typical repair costs for P3440 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. Cylinder deactivation will be disabled, resulting in reduced fuel economy. The short-to-voltage condition should be addressed to prevent prolonged stress on the ECM driver circuit.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P3440 to identify the root cause.
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Quick Info
Category
Powertrain
System
Cylinder Deactivation System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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