P1656Manufacturer-specific code

P1656 Code: VVT Oil Control Valve (OCV) Circuit (Toyota)

On Toyota and Lexus vehicles, the P1656 code means the VVT oil control valve (OCV) circuit is open or shorted. You may notice a rough idle, a loss of power and sometimes a rattle at startup. Other brands may define this number differently.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$20 to $900
Difficulty
Medium
System
Ignition and Misfires
Applies to
Depends on the manufacturer

Common in: Toyota

Updated Reviewed by Renzo Chacca

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What the P1656 code means

P1656 is a manufacturer-specific code: the 1 in the second position means each automaker defines what it means, not the generic SAE standard. The most widespread definition is the one used by Toyota and Lexus. If your vehicle is another brand, confirm the code text with a scan tool that supports that manufacturer.

ManufacturerMeaning of P1656
Toyota and LexusVVT oil control valve (OCV) circuit

The Toyota VVT-i system advances or retards the intake camshaft with a hydraulic gear. The computer controls it with the OCV valve, which meters engine oil, and checks the actual position with the camshaft sensor.

The computer sets the P1656 code when it detects an open or shorted circuit in the OCV valve.

Before you start repairs, confirm the make, model, year and engine. With manufacturer codes, the same number can change even between engines from the same brand.

P1656 code symptoms

  • Check engine light on.
  • Rough idle or an engine that stalls.
  • Loss of power.
  • Higher fuel use.

Likely causes of the P1656 code

  1. Failed OCV valve. The coil is open or shorted.
  2. OCV connector with oil or corrosion.
  3. Wiring. Look for rubbing against the engine, the chassis or the exhaust.
  4. Computer. This is uncommon.

How to diagnose the P1656 code step by step

  1. Check the oil level and condition.
  2. Command the OCV with the scan tool. At idle the engine should shake or stall if it works.
  3. Measure the OCV resistance. It is 6.9 to 7.9 ohms on many engines.
  4. Clean the OCV screen if the engine has one.
  5. Verify the valve timing of the timing chain or belt.

How to fix the P1656 code

  • Change the oil and filter with the correct viscosity.
  • Clean or replace the OCV.
  • Replace the VVT gear if it is damaged.
  • Correct the valve timing if it is off.

Technical reference data

  • OCV resistance: approximately 6.9 to 7.9 ohms at 20 °C (68 °F).
  • Usual oil: 0W-20 or 5W-30 depending on the engine.
  • P1xxx codes are manufacturer-specific: confirm the definition with a scan tool that supports your brand.
  • Reference values: check the manufacturer data for your vehicle.

Brand-specific notes

VVT-i is very sensitive to oil, so oil changes done on time and with the right viscosity matter a lot here.

P1656 on Toyota

Very common on the Corolla, Yaris, RAV4 and Camry. Always use the oil viscosity the manufacturer specifies and change the oil on schedule.

If your vehicle is another brand, check the table above for the meaning its manufacturer gives this code and confirm it with a compatible scan tool.

Frequently asked questions about P1656

What does the P1656 code mean on a Toyota?
It means the VVT oil control valve (OCV) circuit is open or shorted. You may notice a rough idle, a loss of power and sometimes a rattle at startup.
Does P1656 mean the same thing on every brand?
No. It is a manufacturer-specific code, so on other brands it may not exist or may mean something different. Confirm it with a scan tool that supports your make.
Can I drive with a P1656 code?
Yes, with caution. If you hear a metallic knock, have it checked soon, because the P1656 code can point to a problem that gets worse.
How much does it cost to fix P1656?
Roughly $20 to $900 on a Toyota. An oil change or an OCV cleaning is cheap, while a VVT gear or a timing repair sits at the top of the range.
Will a P1656 code clear itself?
Not while the OCV circuit is open or shorted. After a repair, clear the code and make sure the idle is steady.
What is the most common cause of P1656?
A failed OCV valve with an open or shorted coil. A connector with oil or corrosion and damaged wiring come next.

Related codes

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