Toyota Lexus p1656
Toyota/Lexus DTC P1656 – Variable Valve Timing Control Solenoid Circuit Malfunction
What It Means
Diagnostic Trouble Code (DTC) P1656 indicates a malfunction in the circuit controlling the Variable Valve Timing (VVT) control solenoid. This solenoid adjusts the intake camshaft timing to improve engine efficiency, performance, and emissions.
Causes
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Electrical Issues:
- Open or short in the VVT solenoid wiring
- Poor electrical connection at the VVT solenoid or ECM
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Component Failures:
- Faulty VVT control solenoid
- Malfunctioning ECM (Engine Control Module)
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Oil Issues:
- Low engine oil level or pressure
- Contaminated or degraded oil blocking the solenoid
Symptoms
- Check Engine Light: Illuminated MIL (Malfunction Indicator Lamp)
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Engine Performance Issues:
- Rough idling
- Reduced power or acceleration
- Decreased fuel economy
- Possible ticking noise from the engine
Diagnosis
- Scan for Codes: Use an OBD-II scanner to confirm P1656.
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Visual Inspection:
- Check for damaged or disconnected VVT solenoid wiring.
- Inspect the solenoid connector for corrosion or loose pins.
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Test the Solenoid:
- Measure resistance with a multimeter (consult service manual for specs).
- Apply 12V to test if the solenoid clicks, indicating proper function.
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Oil Inspection:
- Check oil level and quality.
- Replace oil and filter if necessary.
Repair Steps
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Address Electrical Problems:
- Repair or replace damaged wiring or connectors.
- Clean connectors to ensure good electrical contact.
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Replace the VVT Solenoid:
- If the solenoid is faulty, install a new one.
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Perform an Oil Change:
- Use the recommended oil type and viscosity for your vehicle.
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ECM Check:
- If all else fails, test or replace the ECM.
Estimated Costs
- Diagnostics: $50–$150
- VVT Solenoid Replacement: $100–$300 (parts and labor)
- Oil Change: $50–$100
- Wiring Repair: $50–$200
