What Does P3459 Mean?
The PCM has detected abnormally low voltage in the cylinder 8 intake valve control circuit. This indicates a short to ground condition somewhere in the control circuit between the PCM and the valve control solenoid.
Common Causes
40%
Wiring harness chafed or shorted to ground/engine block
30%
Internal short to ground in cylinder 8 intake valve control solenoid
15%
Damaged or corroded connector causing short circuit condition
10%
Water or oil intrusion in connector causing low resistance path
5%
PCM internal short circuit on valve control driver output
Diagnostic Steps
1
Step 1: Disconnect cylinder 8 intake valve control solenoid connector and measure resistance to ground on PCM side (should be >10k ohms)
2
Step 2: Inspect wiring harness routing for areas where wire may contact hot engine components or sharp edges
3
Step 3: Measure resistance of intake valve control solenoid; compare to specifications (typically 10-30 ohms, should not have continuity to case ground)
4
Step 4: Check for oil or coolant contamination inside electrical connectors that could create unintended current paths
5
Step 5: If wiring and solenoid test good, suspect PCM internal fault and perform PCM power supply and ground circuit verification
Estimated Repair Cost
$120 - $900
Parts + labor, varies by vehicle and location
The PCM has detected abnormally low voltage in the cylinder 8 intake valve control circuit. This indicates a short to ground condition somewhere in the control circuit between the PCM and the valve control solenoid.
The most common cause of P3459 (Cylinder 8 Deactivation/Intake Valve Control Circuit Low) is: Wiring harness chafed or shorted to ground/engine block
Typical repair costs for P3459 range from $120 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle remains safe to operate. Cylinder deactivation system will be disabled, resulting in reduced fuel economy but no safety risk.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P3459 to identify the root cause.
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Quick Info
Category
Powertrain
System
Variable Valve Timing/Cylinder Deactivation System
Difficulty
Type
Generic (SAE)
Recommended Tools
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