What does fault code P0086 mean?
Fault code P0086, applicable to all vehicle manufacturers, means “Exhaust Valve Control Solenoid Circuit High (Bank 2).”
Background Knowledge: The camshaft’s function is to control the opening and closing of the valves. In a variable valve timing system, the electronic camshaft adjustment valve (or oil control valve, OCV) adjusts the camshaft angle by changing the oil pressure to the camshaft adjuster (mechanical) based on instructions from the Engine Control Module (ECM), ensuring the valves open and close at the optimal time. This fault code appears if the exhaust camshaft adjustment valve circuit voltage exceeds the calibrated maximum value.
Symptoms of Fault Code P0086
- Malfunction Indicator Lamp (Check Engine Light) illuminated
- Difficulty starting the engine
- Unstable idle
- Power loss during acceleration
- Increased fuel consumption
- Engine may stall while driving
Main Causes of Fault Code P0086
- Damaged fuel pressure control valve position sensor
- Compromised wiring or connector integrity
- Short circuit to power in the sensor circuit
- Faulty Engine Control Module (ECM)
How to Diagnose P0086 Error Code?
- Read the fault code with an OBD2 scanner
- Inspect the condition and connectors of the fuel pressure regulator sensor
- Measure voltage and resistance at the circuit contacts
- Check the wiring for open circuits and short circuits
- Test the ECU for control faults
Possible Causes and Diagnostic Methods
| Possible Cause | How to Check? |
| Defective sensor | Measure resistance, compare with technical specifications |
| Wiring issues | Visual inspection for damage and breaks |
| Short circuit in the circuit | Check for short circuits with a multimeter |
| ECU failure | Perform computer diagnostics, check for additional fault codes |
Tools Required: OBD2 diagnostic scanner, multimeter, automotive circuit schematic, toolkit for connector and sensor removal
How to Fix Fault Code P0086? (Problem Solutions)
Simple Repair Methods
- Clear the fault code and test the system
- Check that all connectors are securely connected
- Clean dirt and oxidation from contact points
In-Depth Diagnosis and Repair Plan
- Replace the faulty regulator position sensor
- Repair damaged wiring or replace connectors
- Replace the Engine Control Unit if it is faulty
Troubleshooting by Symptoms
| Symptom | Possible Solutions |
| Engine power loss | Inspect the pressure regulator, replace if necessary |
| Engine stalling | Diagnose wiring and replace damaged sections |
| Check Engine light + instability | Check voltage and test the sensor |
Fault Code P0086 in Common Vehicles
- P0086 in Audi: This error may be accompanied by fuel supply interruptions, especially in turbocharged engines. Accurate circuit diagnosis is required.
- P0086 in BMW: This is often caused by sensor wear and voltage instability. Checking the control circuit and DME unit is recommended.
- P0086 in Chevrolet: In models with GDI (Gasoline Direct Injection) systems, the regulator on the rail may be problematic. Sensor replacement is needed.
- P0086 in Ford: This error may be combined with other fuel system faults. Checking the circuit for short circuits is essential.
- P0086 in Mercedes-Benz: This situation usually occurs with an ECU fault or moisture ingress into connectors. Drying and sealing are recommended.
P0086 FAQ
What should I do if I encounter fault code P0086?
Fault P0086 indicates a problem with the fuel pressure regulator circuit. If the fault is detected, a comprehensive diagnosis of the sensor, wiring, and engine control unit is necessary.
Is it possible to drive with a P0086 error?
Not recommended. A fault can lead to fuel interruptions, power loss, and unstable engine operation, affecting driving safety.
What are the main causes of P0086?
Main causes include faulty valve position sensor, short circuit in wiring, poor contacts, or Engine Control Unit failure.
Is it possible to reset the fault without diagnostics?
The code can be temporarily cleared with a scanner or by disconnecting the battery, but the error will reappear if the cause is not addressed.
Is P0086 related to fuel pump damage?
Sometimes, yes. If the pressure regulator or its circuit fails, symptoms similar to fuel pump failure may appear.
Can I replace the sensor myself?
Yes, if you are certain of the cause and have basic repair skills. However, a full diagnosis is recommended before replacement.
P0086 Related OBD2 Faults
- P0087 – Low Fuel Rail Pressure
Description: Fuel pressure below minimum threshold. Possible causes: Pump failure, clogged filter, damaged regulator.
- P0088 – High Fuel Rail Pressure System
Description: Fuel pressure exceeds allowable standard. Possible causes: Stuck regulator, ECU fault, faulty pressure sensor.
- P0090 – Fuel Pressure Control Valve Control Circuit Malfunction
Description: No signal or open control circuit. Possible causes: Wiring, sensor, control module.
Important! If the P0086 fault appears simultaneously with other fuel system errors, it may indicate a more serious failure in the fuel supply system or engine control unit. Never ignore the illuminated Check Engine light. Even if the engine runs normally, the fault may indicate a hidden issue that could lead to expensive repairs in the long term.