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P0077 Code Explained: Intake Valve Control Solenoid Circuit High Bank 1 Causes, Symptoms & Fixes

P0077 code displayed on an OBD-II scanner with the Bank 1 intake valve control solenoid, high circuit voltage, disconnected wiring, and VVT camshaft actuator highlighted.

If your OBD-II scanner displays P0077, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected a higher-than-expected electrical signal in the Bank 1 intake valve control solenoid circuit.

The generic OBD-II definition for P0077 is:

Intake Valve Control Solenoid Circuit High Bank 1

Depending on the manufacturer or scan tool, the description may appear as:

P0077 is an electrical circuit code involving the solenoid that controls oil flow to the Bank 1 intake camshaft actuator. On certain Hyundai and Kia applications, manufacturer diagnostic information describes P0077 as an intake oil-control-valve circuit that is open or shorted to battery voltage.

Common causes include:

Possible symptoms include:

Because P0077 affects the variable valve timing system, the PCM may disable intake camshaft adjustment and leave the camshaft in a default position until the electrical fault is repaired.

For additional diagnostic information, visit:

P0077 Quick Facts

ItemInformation
OBD-II CodeP0077
DescriptionIntake Valve Control Solenoid Circuit High Bank 1
CategoryPowertrain
SystemVariable Valve Timing
Main ComponentIntake Valve Control Solenoid
Affected SideBank 1
Fault TypeHigh Circuit Voltage
Common Electrical CauseOpen Circuit or Short to Battery
SeverityModerate
Safe to Drive?Sometimes, for a short distance
Typical Repair Cost$100–700

What Does P0077 Mean?

P0077 means the PCM sees voltage or circuit feedback that is higher than expected in the Bank 1 intake valve control solenoid circuit.

The affected circuit may include:

Depending on circuit design, P0077 may be triggered by:

A Hyundai diagnostic reference for P0077 describes the detection strategy as an electrical check for an open circuit or short to battery, with the fault detected when the control circuit remains at battery voltage instead of responding correctly to PCM control.

P0077 is primarily an electrical code. Engine-oil condition still matters because the solenoid controls hydraulic oil flow, but dirty oil alone does not explain a control circuit that remains electrically high.

What Is Bank 1?

Bank 1 is the side of the engine containing cylinder number 1.

On an inline engine, such as an inline four-cylinder or inline six-cylinder, there is only one cylinder bank. That bank is Bank 1.

On a V-type engine, Bank 1 may be located on either side depending on the engine’s cylinder-numbering layout.

Bank 1 is not automatically:

Use the correct:

to identify Bank 1.

Replacing the Bank 2 solenoid because it was easier to reach may improve access to your wallet, but it will not repair P0077.

What Is an Intake Valve Control Solenoid?

The intake valve control solenoid is an electrically operated oil-control valve used by the engine’s variable valve timing system.

Depending on the manufacturer, it may also be called:

The solenoid regulates pressurized engine oil flowing to the intake camshaft actuator or cam phaser.

This allows the PCM to change intake camshaft timing according to:

Variable intake camshaft timing can improve:

P0077 does not necessarily mean the camshaft actuator itself has failed. It means the PCM has detected an electrical problem in the circuit controlling the intake solenoid.

How Variable Valve Timing Works

The variable valve timing system changes when the intake valves open and close relative to crankshaft position.

A typical system includes:

  1. Engine oil supply
  2. Oil passages in the cylinder head
  3. Intake valve control solenoid
  4. Intake camshaft actuator or phaser
  5. Camshaft position sensor
  6. Crankshaft position sensor
  7. PCM control strategy

When the PCM commands a timing adjustment:

If the PCM cannot electrically control the solenoid because the circuit is open or held at excessive voltage, it may store P0077 and disable variable valve timing.

How the Intake Valve Control Solenoid Circuit Works

Many intake VVT solenoids use two electrical terminals.

A common design includes:

The PCM controls solenoid current by rapidly switching the ground side using pulse-width modulation.

The PCM may monitor:

When the PCM commands the circuit low but the voltage remains high, it may interpret the condition as:

Other vehicles may use a high-side control circuit, so the exact meaning of “circuit high” must be confirmed using the correct wiring diagram.

What Does “Circuit High” Mean?

“Circuit high” means the PCM sees electrical voltage or feedback above its expected range.

It does not necessarily mean:

The fault concerns the monitored solenoid circuit.

Common circuit-high conditions include:

On many low-side-controlled circuits, an open connection leaves the control wire near supply voltage. The PCM sees that the circuit remains high when it should have been pulled toward ground.

P0075 vs P0076 vs P0077

CodeDescriptionTypical Meaning
P0075Intake Valve Control Solenoid Circuit Bank 1General electrical circuit malfunction
P0076Intake Valve Control Solenoid Circuit Low Bank 1Circuit voltage below expected range
P0077Intake Valve Control Solenoid Circuit High Bank 1Circuit voltage above expected range

Related Bank 2 codes include:

CodeDescription
P0081Intake Valve Control Solenoid Circuit Bank 2
P0082Intake Valve Control Solenoid Circuit Low Bank 2
P0083Intake Valve Control Solenoid Circuit High Bank 2

P0077 does not automatically prove that the solenoid is bad.

The failure may be located in the:

P0077 vs P0010

P0010 is generally defined as:

“A” Camshaft Position Actuator Circuit Bank 1

P0077 is defined as:

Intake Valve Control Solenoid Circuit High Bank 1

Depending on manufacturer terminology, both codes may involve the Bank 1 intake camshaft oil-control solenoid.

The difference is that P0077 specifically identifies a high electrical circuit condition, while P0010 is a broader actuator-circuit malfunction.

Vehicle-specific service information should determine:

How the PCM Detects P0077

The PCM may set P0077 when:

On one documented Hyundai circuit, the PCM runs the electrical check with battery voltage within a defined operating range and can identify a short-to-battery condition within approximately two seconds. Thresholds and timing vary by vehicle.

The PCM may respond by:

Symptoms of P0077

Possible symptoms include:

Reduced performance, increased fuel consumption, rough running, and occasional starting problems are commonly associated with P0077 and loss of intake-camshaft control.

Symptoms depend on:

Some engines continue running reasonably well with VVT disabled.

Others feel as though the powerband has been replaced with a gently worded suggestion.

Can P0077 Cause a Rough Idle?

Yes.

If the PCM cannot control the intake camshaft, the camshaft may remain in a position that is not ideal for idle.

Possible results include:

However, rough idle can also be caused by:

Confirm that the P0077 circuit fault is active before blaming every idle complaint on the VVT system.

Can P0077 Cause Poor Acceleration?

Yes.

Variable intake camshaft timing helps optimize cylinder filling across different engine speeds and loads.

If VVT operation is disabled, the engine may lose:

The PCM may also limit engine output if it cannot verify safe camshaft control.

Common Causes of P0077

1. Disconnected Intake Valve Control Solenoid

A disconnected solenoid is one of the most common causes of a circuit-high fault.

The connector may have been left unplugged during:

A disconnected connector prevents current flow and may leave the monitored circuit at supply voltage.

2. Open Solenoid Coil

The electrical coil inside the solenoid may break.

Possible causes include:

An open coil normally measures:

The PCM may detect that no current flows when the solenoid is commanded.

3. Broken PCM Control Wire

The control wire may break because of:

A broken wire commonly causes:

The conductor may be broken inside insulation that still appears intact.

4. Control Circuit Shorted to Battery Voltage

The PCM control wire may contact:

Manufacturer-oriented diagnostic references specifically associate P0077 with an open circuit or short to battery in the intake oil-control-valve circuit.

A short to voltage can prevent the PCM from pulling the control circuit low and may damage the PCM driver.

5. Loose Solenoid Connector

A connector that is not fully locked may cause:

Inspect for:

6. Corroded Connector Terminals

Corrosion can increase resistance enough to prevent proper current flow.

Inspect for:

Poor connections and damaged connectors are recognized common causes of P0077.

7. Backed-Out Connector Terminal

A terminal may be pushed backward when the connector is installed.

It may appear connected externally while failing to contact the solenoid pin.

Check for:

A backed-out terminal can make the circuit electrically identical to an unplugged solenoid.

8. Oil Inside the Connector

Engine oil may enter the connector because of:

Oil can:

Repair the leak and replace contaminated terminals or pigtails when necessary.

9. Heat-Damaged Wiring

VVT wiring may be routed near:

Heat may cause:

Inspect missing or damaged heat shields.

10. Chafed Wiring Harness

The harness may rub against:

A chafed wire may alternately:

depending on engine movement.

11. Incorrect Previous Wiring Repair

Poor repairs may include:

A weak connection may add enough resistance to create a circuit-high code.

12. Incorrectly Wired Replacement Connector

A replacement pigtail may have:

Always verify the connector pinout using the wiring diagram.

Matching colors is useful, but previous repairs may have already converted the harness into an automotive guessing game.

13. Failed Intake Valve Control Solenoid

The solenoid may fail electrically or mechanically.

Electrical failures include:

Mechanical failures include:

P0077 points first toward the electrical circuit, but a complete diagnosis should also inspect the solenoid mechanically after the circuit is tested.

14. Incorrect Replacement Solenoid

An incorrect solenoid may have:

An aftermarket solenoid may physically fit while remaining electrically incompatible.

That is not an upgrade. It is a more polished method of storing the same code.

15. Missing PCM Ground Control

On a low-side-controlled circuit, the PCM must ground the solenoid to energize it.

If the PCM cannot pull the circuit low, causes may include:

The solenoid supply side may test correctly while the control side remains at battery voltage.

16. Poor PCM Connector Connection

The PCM connector may have:

Inspect the PCM only after disconnecting the battery and following manufacturer procedures.

17. Blown Fuse or Failed Relay

Circuit design matters.

A failed fuse or relay more commonly removes supply voltage and may trigger a general circuit code, but some monitoring strategies can report a high or open condition when current does not flow as expected.

If several engine actuators have codes, inspect:

Do not replace multiple solenoids before checking the one fuse they all share.

18. High Circuit Resistance

A partially broken wire or corroded terminal may allow voltage to appear on a multimeter while preventing sufficient current flow.

Possible sources include:

A loaded voltage-drop test is more useful than a simple continuity test.

19. Low Engine Oil Level

Low oil level is not normally the direct cause of the high electrical signal.

However, it can cause:

Low oil is frequently listed among broader VVT-system conditions that should be checked during P0077 diagnosis.

Always inspect oil level before commanding the VVT system.

20. Dirty or Sludged Engine Oil

Dirty oil may restrict:

Dirty oil more commonly causes timing-performance codes than a circuit-high code, but it can coexist with an electrically damaged solenoid.

An oil change will not repair an open wire, though it may give the technician something cleaner to lean over while finding it.

21. Incorrect Oil Viscosity

Oil that is too thick or too thin can reduce VVT performance.

Possible effects include:

Use the manufacturer-specified:

22. Clogged Solenoid Screen

Some VVT solenoids contain a fine oil screen.

It may become restricted by:

A clogged screen does not normally create an open electrical circuit, but it may explain continued timing problems after P0077 is repaired.

23. PCM Software Issue

A software or calibration problem may cause the PCM to:

Check for:

Software issues are less common than connector, wiring, and solenoid faults.

24. Failed PCM Driver

The internal PCM driver may fail because of:

A damaged driver may be unable to ground or control the solenoid circuit.

Only suspect the PCM after confirming:

Replacing the PCM before checking whether the solenoid connector is plugged in is automotive diagnostics sponsored by unnecessary expense.

Is P0077 Serious?

P0077 is generally considered a moderate-severity code.

The engine may continue running, but intake camshaft timing may become:

Possible consequences include:

P0077 becomes more serious if:

Can You Drive With P0077?

You may be able to drive a short distance if:

Avoid continued driving if:

P0077 usually will not destroy the engine immediately.

Continuing to drive with low oil pressure or severe timing noise because the scanner mentioned a solenoid is a far more ambitious risk.

How to Diagnose P0077

Step 1: Scan for All Stored Codes

Check for:

Record:

Do not clear the codes before recording diagnostic information.

Step 2: Confirm Bank 1

Identify:

Do not confuse:

Step 3: Check Engine Oil Level

Park the vehicle on level ground.

Verify:

Correct low oil before operating or testing the VVT system.

Step 4: Inspect Oil Condition

Look for:

Perform an oil and filter change when needed, but continue electrical diagnosis because P0077 specifically identifies a circuit-high fault.

Step 5: Locate the Bank 1 Intake Solenoid

The solenoid is commonly mounted:

Use service information to verify the component.

Step 6: Confirm the Connector Is Attached

Before testing anything complicated, verify that the connector is:

P0077 is often caused by an open or disconnected solenoid circuit.

This simple inspection can prevent a lengthy diagnostic journey toward a connector visibly hanging beside the solenoid.

Step 7: Inspect the Solenoid Connector

Disconnect the connector and check for:

Repair connector damage before replacing the solenoid.

Step 8: Inspect the Wiring Harness

Follow the wiring toward the PCM and power distribution system.

Look for:

Pay special attention to the first several inches behind the connector.

Step 9: Measure Solenoid Resistance

Disconnect the solenoid and measure resistance across its terminals.

Compare the measurement with factory specifications.

Possible findings include:

Generic resistance specifications should not be substituted for vehicle-specific data.

Step 10: Check Each Terminal Against the Solenoid Housing

When service information permits, measure resistance between each solenoid terminal and its metal body.

Unexpected continuity may indicate:

Step 11: Reconnect or Substitute a Known-Good Solenoid

When approved, connect:

Observe whether circuit status changes.

If P0077 changes or the monitored circuit returns to normal, the original solenoid may have an open coil.

Use only a test load appropriate for the PCM driver.

Step 12: Verify Solenoid Power Supply

With the ignition on, identify and test the power-supply terminal.

Depending on circuit design, expected voltage may be:

If power is missing, inspect:

Step 13: Load-Test the Power Circuit

A high-impedance multimeter may display normal voltage even through a severely corroded connection.

Use an approved load test to check:

Excessive voltage drop indicates resistance in the circuit.

Step 14: Test the PCM Control Wire for an Open

Disconnect the PCM and solenoid as instructed.

Measure continuity through the control wire.

Check for:

Move the harness while monitoring resistance.

Step 15: Test for a Short to Battery Voltage

With the PCM and solenoid disconnected, test whether the control wire receives voltage from another circuit.

Possible sources include:

A short to battery is a documented P0077 detection condition on some applications.

Step 16: Test for a Short Between Wires

Inspect whether the control circuit is shorted to:

Heat damage can fuse several wires together inside an otherwise normal-looking harness.

Step 17: Check Connector Terminal Tension

Use the manufacturer-approved terminal test tool.

Check for:

Poor terminal tension can create an intermittent open that stores P0077.

Do not insert an oversized meter probe directly into the connector and manufacture the failure yourself.

Step 18: Perform Voltage-Drop Testing

With the circuit operating, test voltage drop across:

Excessive voltage drop indicates unwanted resistance.

Step 19: Command the Solenoid With a Scan Tool

Use a bidirectional scan tool when supported.

Monitor:

Possible results include:

Step 20: Use a Current Clamp

A low-current clamp can measure solenoid current without opening the circuit.

Possible findings include:

Compare with:

Step 21: Examine the Control Signal With an Oscilloscope

An oscilloscope can show:

A circuit that remains near battery voltage while commanded may indicate:

Step 22: Perform a Wiggle Test

Monitor live circuit data while moving:

Watch for:

Step 23: Inspect the Solenoid Mechanically

If the electrical circuit is repaired but VVT performance remains poor, remove the solenoid.

Inspect for:

Mechanical restrictions are more likely to cause P0011, P0012, or similar performance codes than P0077 alone.

Step 24: Compare Bank 1 With Bank 2

On engines with two banks, compare:

Bank 2 can provide a useful reference if both circuits use identical components and control strategies.

Step 25: Swap Solenoids Only When Approved

If the Bank 1 and Bank 2 intake solenoids are confirmed identical, a controlled swap may help isolate the fault.

After swapping:

Do not swap intake and exhaust solenoids unless the manufacturer confirms they are interchangeable.

Step 26: Check PCM Power and Grounds

Before condemning the PCM, verify:

A PCM ground problem may interfere with driver operation and circuit monitoring.

Step 27: Check Technical Service Bulletins

Search manufacturer information using:

Possible factory corrections include:

Step 28: Evaluate the PCM Driver

Only evaluate PCM failure after confirming:

If the PCM cannot switch the circuit and all external wiring tests pass, the driver may require:

Step 29: Verify the Repair

After completing repairs:

  1. Clear all diagnostic trouble codes.
  2. Start the engine.
  3. Confirm normal oil-pressure warning-light operation.
  4. Monitor the intake solenoid command.
  5. Check circuit voltage and current.
  6. Compare desired and actual camshaft timing.
  7. Check idle quality.
  8. Road-test the vehicle under varied load and RPM.
  9. Complete the required drive cycle.
  10. Rescan for pending and confirmed codes.
  11. Confirm P0077 does not return.

Common Repairs and Costs

RepairEstimated Cost
Reconnect or reseat solenoid connector$0–100
Clean electrical connector$50–150
Replace connector terminals$75–250
Engine oil and filter change$60–180
Replace intake valve control solenoid$150–500
Repair open or shorted wiring$150–650
Replace solenoid connector$100–325
Repair engine power-supply circuit$150–700
Replace fuse or relay after repairing fault$75–250
Clean restricted oil passage$200–700
Replace camshaft actuator or phaser$700–2,000+
Replace timing-chain components$1,000–4,000+
Update PCM software$100–300
Replace and program PCM$1,000–2,500+

Actual repair cost depends on:

A disconnected solenoid may require only a few seconds to repair.

An open control wire hidden beneath the intake manifold may require the patience normally reserved for archaeology.

Common Diagnostic Mistakes

Avoid these common P0077 diagnostic mistakes:

P0077 is an electrical circuit-high code.

Replacing the timing chain because the engine has variable valve timing skips several cheaper and considerably more relevant diagnostic steps.

Vehicles Commonly Affected

P0077 is a generic OBD-II code and may appear on various vehicles, including certain:

Manufacturer terminology may include:

P0077 diagnostic information is particularly documented on Hyundai and Kia applications, where the PCM may set the code when the oil-control-valve circuit is open or shorted to battery voltage.

Always use the correct service procedure for the vehicle and engine.

P0077 on Hyundai and Kia Vehicles

Hyundai and Kia may refer to the component as the:

On certain applications, the PCM controls the oil control valve using a duty-cycle signal and monitors the circuit for:

The documented diagnostic logic may identify the fault quickly when battery voltage is within the expected operating range.

Important inspection areas include:

P0077 on Nissan and Infiniti Vehicles

Nissan commonly calls the component the:

Intake Valve Timing Control Solenoid Valve

Possible causes include:

Oil condition and oil pressure should also be checked if additional intake timing-performance codes are stored.

P0077 After Engine Repairs

If P0077 appears after:

inspect for:

A code that appears immediately after repair work should be investigated first in the area that was disturbed.

The PCM is sophisticated, but it still cannot plug in the connector the technician forgot.

P0077 After Replacing the VVT Solenoid

If P0077 appears after installing a new solenoid, check:

A new component may be:

Do not assume the PCM failed because the newly installed part arrived in a box.

Can Dirty Oil Cause P0077?

Dirty oil can contribute to mechanical VVT problems, but P0077 specifically identifies a high electrical circuit condition.

Dirty oil may cause:

Dirty oil does not directly repair or explain:

Check oil condition, but do not abandon electrical diagnosis.

Can a Bad VVT Solenoid Cause P0077?

Yes.

A VVT solenoid can cause P0077 if its internal coil is:

Measure coil resistance and compare it with manufacturer specifications.

Can a Bad Camshaft Position Sensor Cause P0077?

A camshaft position sensor is not a common direct cause of P0077.

The camshaft sensor reports camshaft position, while P0077 monitors the intake valve control solenoid circuit.

A bad camshaft sensor is more likely to set:

Diagnose all stored codes together.

How to Prevent P0077

Reduce the likelihood of P0077 by:

Frequently Asked Questions

What does P0077 mean?

P0077 means the PCM has detected a higher-than-expected electrical signal in the Bank 1 intake valve control solenoid circuit.

What is the full definition of P0077?

The generic definition is:

Intake Valve Control Solenoid Circuit High Bank 1

Where is Bank 1?

Bank 1 is the side of the engine containing cylinder number 1.

An inline engine has only one bank, which is Bank 1.

What does circuit high mean?

Circuit high means the monitored electrical voltage or driver feedback is above the PCM’s expected range.

Common causes include:

Does circuit high mean high engine oil pressure?

No.

The word “high” refers to the electrical circuit signal, not engine-oil pressure.

What causes P0077 most often?

Common causes include:

Is P0077 serious?

P0077 is moderately serious.

The engine may continue running, but performance, fuel economy, idle quality, and emissions may be affected.

Can I drive with P0077?

Possibly for a short distance if:

Stop driving if the oil-pressure light is on, the engine rattles, it stalls, or power loss is severe.

Can P0077 cause a rough idle?

Yes.

Loss of intake camshaft control may cause rough idle, surging, misfires, or stalling.

Can P0077 cause poor acceleration?

Yes.

The engine may lose torque and throttle response if intake valve timing cannot be adjusted.

Can an unplugged VVT solenoid cause P0077?

Yes.

A disconnected solenoid commonly creates an open circuit and may leave the monitored circuit at a high voltage.

Can broken wiring cause P0077?

Yes.

An open control wire or a wire shorted to battery voltage can set P0077.

Can a bad connector cause P0077?

Yes.

Loose, backed-out, corroded, or oil-contaminated terminals can interrupt current flow and cause a circuit-high fault.

Can dirty oil cause P0077?

Dirty oil can contribute to mechanical VVT problems, but P0077 requires electrical testing because it identifies a circuit-high condition.

What is the difference between P0075 and P0077?

P0075 indicates a general Bank 1 intake valve control solenoid circuit malfunction.

P0077 specifically indicates that the circuit signal is above the expected range.

What is the difference between P0076 and P0077?

P0076 indicates a low circuit condition, often involving a short to ground or shorted coil.

P0077 indicates a high circuit condition, often involving an open circuit or short to battery.

Can I test the VVT solenoid with a multimeter?

Yes.

Common tests include:

Use vehicle-specific specifications.

Can I apply battery voltage directly to the solenoid?

Only if the manufacturer’s test procedure permits it.

Incorrect polarity, continuous power, or excessive current can damage the solenoid or wiring.

Does a replacement VVT solenoid require programming?

Usually not.

The vehicle may require:

A replacement PCM requires programming.

How much does P0077 cost to repair?

A basic solenoid replacement typically costs approximately $150–500.

Wiring, connector, PCM, camshaft actuator, or timing-system repairs may cost substantially more.

Final Thoughts

The P0077 code means the PCM has detected a high electrical condition in the Bank 1 intake valve control solenoid circuit.

The most common causes include:

Start diagnosis by:

  1. Scanning for related codes.
  2. Identifying Bank 1 correctly.
  3. Checking oil level and condition.
  4. Confirming the solenoid is connected.
  5. Inspecting connector terminals.
  6. Measuring solenoid resistance.
  7. Verifying supply voltage.
  8. Testing control-wire continuity.
  9. Checking for a short to battery voltage.
  10. Commanding the solenoid with a bidirectional scan tool.
  11. Evaluating the PCM only after external circuits pass.

Do not interpret “circuit high” as high oil pressure or over-advanced valve timing.

P0077 is warning that the electrical circuit remains above its expected voltage. On many systems, that means the circuit is open, the solenoid is disconnected, or the PCM control wire has found an unwanted source of battery voltage.

The repair may be as simple as reconnecting one plug.

It may also involve finding a broken wire buried beneath a collection of engine covers apparently designed to ensure that every two-minute electrical repair begins with 45 minutes of plastic removal.

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