What Does P3456 Mean?
The PCM has detected a voltage signal higher than expected in the cylinder 7 exhaust valve control circuit. This indicates an open circuit, high resistance, or loss of ground in the exhaust valve solenoid control circuit.
Common Causes
35%
Open circuit in wiring harness to cylinder 7 exhaust valve solenoid
30%
Failed cylinder 7 exhaust valve control solenoid with open coil winding
20%
Loose, corroded, or damaged connector at exhaust valve solenoid
10%
Poor ground connection in exhaust valve control circuit
5%
PCM driver circuit malfunction
Diagnostic Steps
1
Step 1: Disconnect cylinder 7 exhaust valve solenoid and measure coil resistance; infinite reading indicates open solenoid coil
2
Step 2: Check for battery voltage at solenoid power supply wire with key on; verify PCM is providing proper control signal
3
Step 3: Inspect connector for loose fit, corrosion, pushed-back pins, or moisture; perform wiggle test while monitoring live data
4
Step 4: Trace wiring harness from solenoid to PCM checking for breaks, cuts, or damage; repair as necessary
5
Step 5: Verify ground circuit integrity with voltage drop test; should be less than 0.1V during solenoid operation
Estimated Repair Cost
$150 - $850
Parts + labor, varies by vehicle and location
The PCM has detected a voltage signal higher than expected in the cylinder 7 exhaust valve control circuit. This indicates an open circuit, high resistance, or loss of ground in the exhaust valve solenoid control circuit.
The most common cause of P3456 (Cylinder 7 Exhaust Valve Control Circuit High) is: Open circuit in wiring harness to cylinder 7 exhaust valve solenoid
Typical repair costs for P3456 range from $150 to $850, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive but should be repaired soon. Will experience reduced fuel economy and possible rough running during cylinder deactivation events.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P3456 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Variable Valve Timing/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.
