P0020 "A" Camshaft Position Actuator Circuit/Open (Bank 2)

The P0020 trouble code indicates an electrical problem in the circuit that controls the “A” camshaft position actuator on Bank 2.

This code is different from a camshaft timing code where the ECM detects that the camshaft is physically in the wrong position. With P0020, the first area to investigate is the electrical circuit controlling the camshaft actuator.

The actuator is usually part of the engine's variable valve timing (VVT) system. The ECM controls an oil control solenoid to regulate the camshaft timing mechanism. If the electrical circuit is open, disconnected, or otherwise unable to operate the actuator correctly, the ECM can store P0020.

The Important Part of P0020: "Circuit/Open"

The word “Open” is particularly important in this code.

The ECM expects to control the camshaft actuator through an electrical circuit. If that circuit is interrupted, current cannot flow as intended.

An open circuit can be caused by something as simple as a disconnected connector or broken wire. It can also result from a damaged terminal, corrosion, an internal failure of the VVT solenoid, or a problem in the circuit between the actuator and ECM.

Therefore, P0020 should initially be approached as an electrical circuit diagnosis, rather than assuming that the camshaft itself has a mechanical timing problem.

What Does the Camshaft Actuator Do?

Variable valve timing allows the engine to alter camshaft timing while the engine is running.

The ECM uses an electrically controlled oil control valve to regulate oil flow to the camshaft phaser. Changing the oil flow changes the position of the phaser and therefore changes when the valves open and close.

The system can adjust camshaft timing according to engine speed, load, temperature, and other operating conditions.

When P0020 is present, the ECM may be unable to control this system because the electrical path to the actuator is not functioning correctly.

That means the engine may still run, but the VVT system may remain in a limited or default position.

Where Should You Look First?

The VVT actuator/solenoid connector and wiring are usually among the first things worth inspecting.

The actuator is mounted on the engine, where it is exposed to:

• Engine heat

• Oil

• Vibration

• Moisture

• Engine movement

Over time, wiring can become brittle or rub against nearby components.

A connector that appears plugged in can still have a problem if a terminal has pushed backward, lost tension, or become corroded.

Common Causes of P0020

Broken or disconnected wiring

A broken control wire can completely interrupt communication between the ECM and VVT actuator.

This can happen after engine repairs, harness movement, vibration, or contact with hot components.

Damaged connector

A loose connector or damaged terminal can create an open circuit even when the connector appears physically connected.

Failed VVT control solenoid

The actuator itself may have an internal open circuit. In that situation, the wiring may be completely intact while the solenoid's internal coil has failed.

Corrosion or water intrusion

Moisture entering the connector can corrode the terminals and interrupt the electrical connection.

Harness damage

The wiring may be melted, chafed, stretched, or crushed.

This is particularly important where the harness passes close to the exhaust system or other hot engine components.

Fuse or power-supply problem

Some VVT systems receive power through a shared fuse or relay. A power-supply problem can therefore prevent the actuator from operating.

The exact circuit arrangement varies by vehicle.

Poor electrical connection

High resistance or poor terminal contact can interfere with actuator operation even if a basic continuity check appears normal.

ECM driver fault

The ECM contains the circuitry that controls the actuator. An internal driver failure is possible, but it should generally be considered only after the actuator and wiring have been properly tested.

P0020 Symptoms

The symptoms depend on how the engine's VVT system behaves when the actuator circuit stops functioning.

Possible symptoms include:

• Check Engine Light

• Reduced engine performance

• Poor acceleration

• Hesitation

• Rough idle

• Increased fuel consumption

• Difficult starting

• Engine misfires

• Reduced low-speed torque

• Poor high-speed performance

• Increased emissions

Some engines can continue running reasonably well because the ECM uses a default camshaft position when VVT operation is unavailable.

In other engines, the loss of variable valve timing can have a much more noticeable effect on drivability.

Start With a Visual Inspection

P0020 is one of those codes where a careful visual inspection can sometimes reveal the problem immediately.

Inspect the actuator connector and harness carefully.

Look for:

• Broken wires

• Exposed copper

• Melted insulation

• Oil inside the connector

• Corroded terminals

• Bent pins

• Loose terminals

• Harnesses rubbing against the engine

• Previous wiring repairs

Pay particular attention to areas where the harness may have been disturbed during previous engine work.

Don't Assume the Solenoid Is Bad

A common diagnostic mistake is to see an actuator-circuit code and immediately replace the VVT solenoid.

That can be an expensive way of solving the wrong problem.

For example, imagine the solenoid is perfectly functional but one of its control wires has broken inside the insulation.

Replacing the solenoid would change nothing.

The circuit needs to be tested from the actuator back toward the ECM.

Electrical Testing Is the Key

The exact test procedure depends on the vehicle's wiring design.

Using the manufacturer's wiring diagram, identify the actuator's:

• Power supply

• Control circuit

• Ground arrangement

• ECM terminal

• Fuse or relay supply

Then determine whether the actuator is receiving the correct electrical conditions.

Testing may involve checking:

• Supply voltage

• Ground

• Coil resistance

• Continuity

• Short to ground

• Short to power

• Voltage drop

• ECM control signal

A simple continuity test is not always enough.

A wire can have continuity when measured with almost no load but fail when the circuit is actually operating. Voltage-drop testing and harness movement testing can expose these problems.

Check the VVT Solenoid Resistance

If the actuator contains an electrical coil, its resistance can be measured.

However, there is no universal resistance value for a P0020 actuator.

The correct specification must come from the manufacturer.

A resistance measurement that is considered normal on one engine may be incorrect on another.

An open reading where the manufacturer's specification expects a measurable coil resistance can indicate an internal open circuit.

Likewise, an extremely low resistance can indicate an internal short.

Inspect the Circuit for an Open

When P0020 is stored, an open circuit is one of the most important possibilities to investigate.

A broken conductor can occur:

• Inside the connector

• Near the connector strain relief

• Inside the wiring harness

• At a previous repair

• Where the harness bends

• Where the harness contacts the engine

A visual inspection may not reveal an internal break.

A wiggle test while monitoring the circuit can sometimes expose an intermittent connection.

What About the Camshaft Position Sensor?

The camshaft position sensor is not the same component as the camshaft position actuator.

This distinction is important.

The sensor tells the ECM where the camshaft is positioned.

The actuator or VVT solenoid is involved in changing the camshaft timing.

P0020 primarily points toward the electrical circuit controlling the actuator. Therefore, replacing the camshaft position sensor simply because P0020 is present is generally not the logical first repair.

Can a Fuse Cause P0020?

Yes, depending on the vehicle's circuit design.

Some systems use a shared power supply for one or more VVT actuators.

If the relevant fuse is blown, the actuator may lose its power supply and the ECM can detect a circuit problem.

However, if a fuse is blown, don't simply replace it repeatedly.

A blown fuse can be the result of a short circuit in the actuator or wiring. The cause of the fuse failure needs to be established.

Could Engine Oil Cause P0020?

Engine oil problems can cause VVT operation problems, but they are not normally the first explanation for a true circuit/open fault.

Dirty oil, low oil pressure, or restricted oil passages can affect the mechanical operation of the VVT system.

However, P0020 specifically concerns the electrical actuator circuit.

If the electrical circuit is confirmed to be intact, then oil pressure, oil flow, and mechanical VVT operation can be investigated if the engine also has timing-related symptoms or additional codes.

A Better Way to Diagnose P0020

A practical diagnostic sequence is:

First, scan the vehicle for all DTCs.

Don't isolate P0020 from other codes. Additional VVT, voltage, or engine-control codes may provide important information.

Next, inspect the actuator connector and harness.

This is often the fastest way to find an open circuit.

Then identify the circuit using the manufacturer's wiring diagram.

Determine exactly how the actuator receives power and how the ECM controls it.

Test the actuator itself.

Measure resistance and perform the manufacturer's recommended actuator tests.

Test the wiring under realistic conditions.

Check for open circuits, shorts, excessive resistance, and voltage drop.

Finally, evaluate the ECM control side.

Only after the actuator and wiring have been proven good should an ECM driver problem become a serious consideration.

Why P0020 Can Appear After Engine Repairs

An actuator circuit code can sometimes appear after work has been performed around the engine.

The VVT harness may have been:

• Left disconnected

• Incorrectly routed

• Pinched

• Pulled during reassembly

• Damaged by heat

• Connected incorrectly

• Left with a poorly seated terminal

If P0020 appeared immediately after engine, cylinder-head, intake, exhaust, timing-chain, or other related work, inspect anything that was disturbed during the repair before replacing components.

Is P0020 Serious?

P0020 should be diagnosed, but the severity depends on how the engine responds when VVT operation is lost.

If the engine runs normally apart from the Check Engine Light, the vehicle may remain driveable for a limited period.

However, if P0020 is accompanied by:

• Severe misfires

• Significant power loss

• Difficult starting

• Engine stalling

• Timing-chain noise

• Multiple camshaft timing codes

the problem should be investigated promptly.

A VVT electrical fault can prevent the engine from controlling valve timing correctly, and another underlying mechanical problem may exist alongside the circuit fault.

What Repairs Can Fix P0020?

The correct repair depends on what testing finds.

Possible repairs include:

• Reconnecting the VVT actuator

• Repairing a broken wire

• Replacing damaged wiring

• Repairing connector terminals

• Removing corrosion

• Correcting a poor electrical connection

• Replacing a defective VVT actuator/solenoid

• Replacing a blown fuse after finding and repairing its cause

• Repairing a power or ground circuit

• Repairing the ECM control circuit

• Replacing or repairing the ECM in rare cases

The important point is that the circuit should be proven faulty before parts are replaced.

Final Thoughts

P0020 is primarily an electrical problem involving the “A” camshaft position actuator circuit on Bank 2. The most likely areas to investigate are the VVT actuator, its connector, wiring, power supply, and control circuit.

The word “Open” is especially significant. A broken wire, disconnected connector, damaged terminal, or internally open actuator can prevent the ECM from controlling the VVT system even though the engine itself is mechanically intact.

A proper diagnosis should therefore start at the actuator and follow the electrical circuit systematically. Only after the circuit has been verified should attention move toward less common possibilities such as an ECM failure or a separate mechanical VVT problem.