What Does P3439 Mean?
The ECM has detected an abnormally low voltage on the cylinder 5 exhaust valve control solenoid circuit. This indicates a short to ground condition in the solenoid or its wiring, pulling the circuit voltage below the expected threshold. The cylinder deactivation system cannot properly control the exhaust valve on cylinder 5.
Common Causes
40%
Short to ground in the wiring harness for the cylinder 5 exhaust valve solenoid
30%
Internally shorted cylinder 5 exhaust valve solenoid coil
20%
Water or oil contamination at the VLOM connector creating a low-resistance ground path
10%
ECM ground-side driver malfunction holding the circuit low
Diagnostic Steps
1
Step 1: Disconnect the cylinder 5 exhaust valve solenoid at the VLOM. Clear codes and check if the code returns. If it clears, the solenoid is internally shorted.
2
Step 2: Measure solenoid coil resistance — expect 5-12 ohms. A reading below 3 ohms indicates a shorted coil winding.
3
Step 3: With the solenoid disconnected, measure resistance from each harness wire to chassis ground. Any reading below 10K ohms indicates a short to ground in the wiring.
4
Step 4: Physically inspect the harness from the VLOM to the ECM for chafed insulation, heat damage, or pinch points where the wire may contact ground.
5
Step 5: If the solenoid and wiring test normal, use scan tool to monitor the ECM driver command state while checking the circuit voltage. An ECM that holds the circuit low without a command indicates an internal driver fault.
Estimated Repair Cost
$100 - $650
Parts + labor, varies by vehicle and location
The ECM has detected an abnormally low voltage on the cylinder 5 exhaust valve control solenoid circuit. This indicates a short to ground condition in the solenoid or its wiring, pulling the circuit voltage below the expected threshold. The cylinder deactivation system cannot properly control the ex...
The most common cause of P3439 (Cylinder 5 Exhaust Valve Control Circuit Low) is: Short to ground in the wiring harness for the cylinder 5 exhaust valve solenoid
Typical repair costs for P3439 range from $100 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle can be driven safely. Cylinder deactivation will be disabled. A short to ground could cause excess current draw on the ECM driver, so timely repair is advisable to prevent secondary damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P3439 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
A quality scan tool helps you read codes, view live data, and clear faults.
