Cylinder 1 Exhaust Valve Control Circuit High
The P3408 code indicates that the powertrain control module (PCM) has detected a high voltage condition in the exhaust valve control circuit for cylinder 1. This circuit is part of a variable valve timing or cylinder deactivation system, often found in engines with Active Fuel Management (AFM) or Variable Valve Timing (VVT). The high voltage reading suggests a short to power, open circuit, or faulty component in the solenoid or wiring.
01. Most Common Causes
- Faulty exhaust valve control solenoid on cylinder 1
- Short to power in the wiring or connector
- Open circuit in the control circuit
- Corroded or damaged connector pins
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Reduced engine power or performance
- Poor fuel economy
- Possible engine stalling
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the wiring and connector for cylinder 1 exhaust valve control solenoid for damage, corrosion, or shorts.
Step 3: Test the solenoid resistance with a multimeter; compare to manufacturer specs (typically 10-30 ohms).
Step 4: Check for voltage at the solenoid connector with key on; should be battery voltage on one pin and ground on the other.
Step 5: If wiring and solenoid are okay, test the PCM output by backprobing the circuit and monitoring with a scan tool.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause engine misfire, reduced performance, and potential damage to the catalytic converter.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, including parts like a solenoid ($30-$80) and labor.