P0086 trouble code definition
P0086 is a OBD2 diagnostic trouble code indicating a fault within the exhaust valve control circuit. This code is similar to P0085 and P0084.
What the P0086 code means
P0086 is a DTC when high voltage is found in the exhaust valve control solenoid circuit bank 2. The fault is triggered when the ECU tries to control the solenoid and finds the voltage to be out of range with high voltage present, this triggers a Check Engine Light to be set on the dashboard. Once this light is set the vehicle is put into a failsafe mode to prevent damage and disabling variable valve timing.
What causes the P0086 code?
- Failed bank 2 exhaust valve control solenoid
- ECU that has failed
- Poor electrical connection
- Wiring harness that has an open or short
What are the symptoms of the P0086 code?
Any felt symptoms will be preceded by the Check Engine Light being displayed on the dash. Once this Check Engine Light is set, a failsafe mode is set to prevent any further damage to the vehicle or engine.
This disabled the variable valve timing which may decrease fuel economy and result in slower than normal vehicle acceleration. The failsafe mode will remain until the code is cleared or the fault is resolved.
How does a mechanic diagnose the P0086 code?
A scan tool is used to check for any codes present.
All of the freeze frame data associated with each code will be checked to tell us about the conditions that the code was triggered under.
The codes will then be cleared and the vehicle will be taken on a test drive under similar conditions as the freeze frame data.
Once the code is seen again on the test drive, a visual inspection will be performed to look for any damage, loose connections, or shorted wiring.
The scan tool will then be used to monitor live solenoid operation.
If the solenoid passes all tests, then the ECU will need to be tested by manufacturer specific testing procedures.
Common mistakes when diagnosing the P0086 code
Most commonly mistakes are made when steps are not followed or are skipped entirely.
The solenoid operation must be tested before it is replaced, even though it is normally the cause of P0086.
How serious is the P0086 code?
P0086 should not prevent the vehicle from being driven to a safe location after the DTC is set. Though caution should be taken with the vehicle if it has a lack of power when acceleration and poor gas milage. The vehicle will operate normally once the fault is repaired.
What repairs can fix the P0086 code?
- Engine control Module replacement
- Repair or replace wiring issues
- Bank 2 exhaust valve control solenoid replacement
- Fixing poor electrical connection
Additional comments for consideration regarding the P0086 code
The Variable valve timing system uses the ECU to control the bank 1 and 2 intake and exhaust control solenoids. This system is used to change valve timing as needed to increase engine power and offer improved fuel economy.
Bank 2 is typically found on the passenger side of the engine compartment. The exhaust valve solenoid is usually located near the exhaust manifold on the engine cylinder head.
An advanced scan tool is required to properly diagnose P0086. These scan tools offer the ability to view sensor and solenoid operation and its changes over time. This helps technicians diagnose electrical issues especially intermittent faults that would otherwise be hard to track down.
Need help with a P0086 code?
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This article originally appeared on YourMechanic.com as P0086 OBD-II Trouble Code: Exhaust Valve Control Solenoid Circuit High (Bank 2) and was authored by Spencer Clayton.