Intake Valve Control Solenoid Circuit High (Bank 1)
The P0077 code indicates that the Powertrain Control Module (PCM) has detected a voltage signal from the intake valve control solenoid circuit on Bank 1 that is higher than the specified range. This solenoid is part of the variable valve timing (VVT) system, which adjusts intake valve timing for optimal performance and emissions. A high voltage condition typically points to a short to power, a faulty solenoid, or a wiring issue.
01. Most Common Causes
- Faulty intake valve control solenoid
- Short to power in the solenoid circuit
- Damaged wiring or connector
- Corroded or loose electrical connections
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance
- Poor fuel economy
- Rough idle or stalling
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P0077 and check for other codes.
Step 2: Visually inspect the intake valve control solenoid and its wiring for damage, corrosion, or loose connections.
Step 3: Test the solenoid resistance with a multimeter; compare to manufacturer specs (typically 6-12 ohms).
Step 4: Check for voltage at the solenoid connector with the engine running; should be within 12V range.
Step 5: If wiring and solenoid are okay, test the PCM output signal; replace PCM if necessary.
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 reduced performance and potential engine damage. You should diagnose and repair the issue promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the cause. A solenoid replacement is usually around $100-$200, while wiring repairs may be less.