P0077🔧 Variable valve timing (intake camshaft oil control solenoid)Stop and fix promptly

P0077: Intake Valve Control Solenoid Circuit High Bank 1 (Meaning, Causes, Fixes)

Reviewed 2026-10-24 · Based on 2 cited source(s)

What P0077 means

On engines with variable valve timing, the engine computer (ECM/PCM) moves the camshaft by sending engine oil through a control solenoid. OBD-Codes.com explains that the computer drives this solenoid with a pulse width modulated (PWM) signal and watches that signal; if the voltage is above specification, it sets P0077 and turns on the check engine light. Bank 1 is the side of the engine with cylinder number 1, and OBD-Codes.com says the intake valve control solenoid is usually on the intake manifold side of the cylinder head. It is a generic code that applies to all makes from 1996 on, though repair steps vary by model. The sources differ in a few ways. OBD-Codes.com describes a purely electrical fault (an open circuit, a bad connection or a short to power), while RepairPal says the code sets when the PCM finds an issue with the solenoid's signal but lists engine oil problems among the common causes. RepairPal's write-up also says this intake solenoid controls the exhaust valve and lists an exhaust valve control solenoid failure as a cause, which conflicts with the code's own name and with OBD-Codes.com; on a P0077 it is the bank 1 intake solenoid that should be checked. RepairPal's severity (Urgent) and its 'engine may not start' symptom are also stronger than anything OBD-Codes.com lists. OBD-Codes.com says this code is similar to P0075 and P0076, which cover the same bank 1 solenoid circuit, and may be accompanied by P0026.

Severity: can I keep driving?

Stop and fix promptly

Get it checked soon and avoid hard driving until then. RepairPal rates P0077 Urgent, meaning immediate action is needed, and lists decreased engine performance, higher fuel use and, in some cases, an engine that may not start. OBD-Codes.com gives no severity rating and lists milder symptoms: the check engine light, poor acceleration and lower fuel economy. Check your engine oil level right away, since RepairPal lists low or wrong-spec oil among the causes.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. Poor or disconnected wiring harness connections (OBD-Codes.com), or another wiring issue (RepairPal)
  2. Open circuit inside the intake valve control solenoid (OBD-Codes.com; RepairPal lists a failed exhaust valve control solenoid)
  3. Short to power in the solenoid wiring (OBD-Codes.com)
  4. Engine oil level too low (RepairPal only)
  5. Engine oil that doesn't meet the manufacturer's requirements (RepairPal only)
  6. Faulty engine computer (ECM/PCM) (OBD-Codes.com, RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Check the engine oil level and make sure the oil matches your owner's manual spec; RepairPal lists low or wrong oil as common causes and an oil and filter change as the common repair.
  2. Find the bank 1 intake valve control solenoid, usually on the intake side of the cylinder head on the cylinder 1 side, and look for unplugged connectors, corrosion or loose wires.
  3. OBD-Codes.com notes the solenoid can be switched on its power side or its ground side depending on the vehicle, so check a factory wiring diagram to see how your circuit works before testing.
  4. With the solenoid and computer connectors unplugged, OBD-Codes.com describes checking each solenoid wire end to end with a multimeter on the ohms setting. An over-limit reading may mean an open wire, a loose connection or a bad terminal.
  5. To test the solenoid itself, measure resistance across its two terminals and compare it with the factory spec or a known good solenoid. OBD-Codes.com says an over-limit or very low reading means the solenoid is likely faulty.
  6. To check for a short to power, OBD-Codes.com says to unplug the computer connector, set the meter to volts, put the negative lead on ground and the positive lead on each solenoid wire. Any voltage present may mean a short to power; unplug connectors and work back toward the solenoid to find it.
  7. If wiring and solenoid test good, OBD-Codes.com suggests comparing the duty cycle commanded on an advanced scan tool with the actual signal at the solenoid using an oscilloscope or graphing multimeter at different engine speeds and loads. A signal from the computer that is constantly on may mean a computer fault.

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • The engine won't start or runs poorly along with the code
  • You don't have a wiring diagram, multimeter or a scan tool that shows solenoid duty cycle
  • The code returns after an oil change and a wiring repair or new solenoid
  • Other camshaft timing codes such as P0026, P0011 or P0014 are also set
  • Tests point to the engine computer, which may need programming to your vehicle

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Can I drive with P0077?

Only carefully and for a short time. RepairPal rates it Urgent and says the engine may lose performance or even fail to start, while OBD-Codes.com lists poor acceleration and lower fuel economy. Check the oil level first and get it diagnosed soon.

What does 'circuit high' mean on P0077?

OBD-Codes.com says the engine computer watches the solenoid's control signal and sets P0077 when that voltage is above specification. Its listed causes are a poor or disconnected connection, an open circuit in the solenoid, a short to power, or a faulty computer.

Can low oil cause P0077?

RepairPal lists low engine oil and oil that doesn't meet the manufacturer's requirements as common causes, because the timing solenoid works with engine oil pressure. OBD-Codes.com treats P0077 as an electrical fault, so check both the oil and the wiring.

How much does it cost to fix P0077?

Neither source gives a repair cost for P0077. It can be as simple as an oil change or a loose connector, or it may need a new solenoid, so diagnose it before buying parts.

Sources

  1. OBD-Codes.com: P0077 Intake Valve Control Solenoid Circuit High (Bank 1)
  2. RepairPal: P0077 Intake Valve Control Solenoid Circuit High (rated Urgent)

Last reviewed 2026-10-24. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.