P0039
Fix within a few daysThe engine computer detects a problem with the electrical circuit that controls the turbocharger or supercharger bypass valve.
Code P0039 means the engine computer sees an issue with the turbo/supercharger bypass valve control circuit. Common causes: Bypass valve solenoid (70%), wiring (20%). Drivability: Yes, but with reduced power. Repair cost: $50-$250 DIY, $150-$500 professional.
Can I Drive With P0039?
Yes, for short trips only
Essential trips under 10 miles, avoid highways and heavy acceleration
Stop driving immediately if: Flashing CEL, loud abnormal noises from the engine or turbo, significant power loss, or burning smell.
Symptoms of P0039
- 1Check Engine Light is on
- 2Reduced engine power or 'limp mode'
- 3Poor acceleration
- 4Engine may sound different under acceleration
- 5Turbocharger or supercharger may not engage properly
Common Causes of P0039
Parts most likely causing this code, ranked by probability
The solenoid itself can fail electrically (open/short circuit) or mechanically (stuck open or closed), preventing proper boost control.
70% of P0039 cases are fixed by replacing this part
Damaged, corroded, or loose wiring and connectors can interrupt the electrical signal to the bypass valve solenoid.
20% of P0039 cases are fixed by repairing wiring or connectors
A leak in the vacuum lines or a faulty vacuum actuator can prevent the bypass valve from operating correctly, triggering a control circuit error.
8% of P0039 cases are fixed by repairing vacuum system issues
A rare internal fault within the PCM's driver circuit for the bypass valve solenoid can cause this code.
2% of P0039 cases are fixed by replacing the PCM
Check These First (Before Buying Parts)
- Visually inspect the bypass valve solenoid and its electrical connector for any visible damage, corrosion, or loose connections.
- Check all vacuum lines connected to the turbo/supercharger system for cracks, leaks, or disconnections (if your system uses vacuum control).
How to Diagnose P0039
- 1Visually inspect the bypass valve solenoid, its wiring harness, and connector for any obvious damage, corrosion, or loose connections.
- 2Check all vacuum lines connected to the turbo/supercharger system for cracks, leaks, or disconnections (if applicable).
- 3Using a multimeter, test the resistance of the bypass valve solenoid; compare to factory specifications.
- 4With the engine off, check for proper voltage at the bypass valve solenoid connector (refer to service manual for specific pinouts and values).
- 5If possible, use an advanced scan tool to command the bypass valve solenoid on and off to check for mechanical operation and electrical response.
P0039 on Popular Vehicles
Ford F-150
2011-2024Commonly seen on EcoBoost engines. The turbocharger bypass valve solenoid can fail due to heat and wear, leading to this code and reduced power.
75% fixed by replacing the bypass valve solenoid
Chevrolet Silverado
2014-2024For turbocharged Silverado models, the bypass valve solenoid or its wiring are the primary culprits. Inspect the harness for chafing near engine components.
70% fixed by replacing the bypass valve solenoid or repairing wiring
Honda Civic
2016-2024On 1.5L turbocharged Civic models, P0039 often relates to the turbocharger wastegate or bypass valve actuator. Check for vacuum leaks if applicable, and inspect the electrical connection to the actuator.
65% fixed by replacing the bypass valve solenoid/actuator
Frequently Asked Questions
What does P0039 mean?
P0039 indicates the engine's computer has detected an electrical problem with the circuit that controls the bypass valve for your turbocharger or supercharger. This valve is critical for regulating boost pressure.
Can I drive with P0039?
Yes, you can drive with P0039, but expect reduced engine power and acceleration. The engine may enter 'limp mode' to protect itself. Fix this within a few days to prevent potential damage to the turbocharger or other engine components.
Will P0039 clear itself?
No, P0039 will not clear itself. The underlying electrical or mechanical fault must be repaired. After the repair, you will need to clear the code with a scan tool, or it will clear after several drive cycles if the fault is resolved and no longer detected.
How do I fix P0039 myself?
Start by visually inspecting the bypass valve solenoid and its wiring. Check for loose connections, corrosion, or damaged wires. If the wiring is good, test the solenoid's resistance with a multimeter. If the solenoid is faulty, replacing it is a common DIY fix.
How much does it cost to fix P0039?
DIY repair costs for P0039 typically range from $50 to $250 for a new bypass valve solenoid. Professional shop repair costs are between $150 and $500, which includes parts and 1-2 hours of labor.
P0039 keeps coming back - why?
If P0039 keeps returning, it means the root cause was not fully addressed. This often points to a persistent wiring issue that was missed, a faulty replacement part, or a less common problem like a vacuum leak or a rare PCM fault.
Will P0039 fail emissions/smog test?
Yes, P0039 will cause your vehicle to fail an emissions or smog test. A Check Engine Light indicates an active fault in the emissions-related systems, which includes proper engine operation and boost control.
What's the difference between P0039 and P0234?
P0039 specifically points to an electrical circuit issue with the turbo/supercharger bypass valve control. P0234 indicates an 'Engine Overboost Condition,' meaning the turbo/supercharger is producing too much boost, which can be a symptom of a stuck bypass valve or other boost control issues, but P0039 is about the electrical control circuit itself.
P0039 on Ford F-150 EcoBoost
On Ford F-150s with EcoBoost engines, P0039 is frequently caused by a failing turbocharger bypass valve solenoid. These solenoids can become sticky or fail electrically over time, leading to boost control issues. Inspect the solenoid and its electrical connector first.
Questions to Ask Your Mechanic
Did you test the resistance of the bypass valve solenoid and compare it to factory specifications?
Good answer: Yes, the solenoid's resistance was X ohms, and the factory spec is Y ohms. It's out of range, indicating an internal fault.
Did you check the voltage and ground at the bypass valve solenoid connector?
Good answer: Yes, we confirmed proper voltage and ground at the connector, so the wiring from the PCM is good. The problem is likely the solenoid itself.
Have you inspected all vacuum lines and the bypass valve for proper mechanical movement?
Good answer: Yes, all vacuum lines are intact with no leaks, and we manually checked the bypass valve for free movement. It's not physically stuck.
Repair Cost Estimate
DIY Repair
Parts only
$50-$250
Shop Repair
Parts + labor
$150-$500
Save $100-$250 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate - requires basic hand tools, a multimeter for testing, and potentially a scan tool. Access to the solenoid can be challenging on some vehicles.
Cost of Waiting
Ignoring P0039 can lead to continued reduced engine power and potentially cause premature wear or damage to your turbocharger/supercharger due to improper boost regulation. A $100-$250 solenoid replacement now prevents a $1,000-$3,000 turbocharger replacement later.
While You're In There...
If you are already accessing the turbo/supercharger area, checking or replacing the boost pressure sensor can prevent future boost-related codes, as it often operates in the same environment.
If the repair requires removing the intake manifold, replacing the gaskets is a smart preventative measure to avoid future vacuum leaks and repeat labor.
Tools You'll Need
- Basic hand tools (sockets, wrenches)
- Multimeter
- Wire stripper/crimper (if wiring repair is needed)
- Scan tool (to clear codes and potentially command solenoid)
P0039 is a common code on forced induction engines. Most repairs involve replacing a relatively inexpensive solenoid, and your engine will regain its full power afterward.
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Your Next Steps
Step 1: Perform a thorough visual inspection of the bypass valve solenoid, its wiring harness, and any associated vacuum lines. Look for frayed wires, corroded pins, or disconnected hoses.
Step 2: If the visual inspection reveals no obvious issues, use a multimeter to test the resistance of the bypass valve solenoid. Compare your reading to the resistance specified in your vehicle's service manual. An out-of-spec reading confirms a faulty solenoid.
Step 3: If the solenoid tests good, check for proper voltage and ground at the solenoid's electrical connector. If power is missing, the issue is in the wiring back to the PCM or the PCM itself. Parts you'll likely need: a new turbocharger/supercharger bypass valve solenoid.