Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car has a part that helps control how the gears shift. This code means that part is getting too much power.
The pressure control solenoid 'M' is a part of the transmission system that helps manage the pressure of the transmission fluid, ensuring smooth gear shifts. A 'Control Circuit High' error indicates that the electrical circuit controlling this solenoid is experiencing higher than expected voltage.
The P27B8 code is triggered when the Powertrain Control Module (PCM) detects a high voltage condition in the control circuit of the pressure control solenoid 'M'. This solenoid is responsible for regulating hydraulic pressure in the transmission to optimize gear shift quality. A high voltage condition may indicate a short to power or an open circuit.
• Harsh or erratic shifting
• Transmission slipping
• Illuminated Check Engine Light
• Faulty pressure control solenoid 'M'
• Wiring issues such as a short to power or open circuit
• Faulty PCM or transmission control module
PCM: Powertrain Control Module
Solenoid: An electromechanical device used to control fluid flow
• Use an OBD-II scanner to confirm the code.
• Inspect wiring and connectors for damage or corrosion.
• Test the pressure control solenoid 'M' for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the faulty pressure control solenoid 'M'.
• Reprogram or replace the PCM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regular transmission fluid checks and changes.
• Inspect wiring harnesses for wear.
• Avoid overloading the vehicle.
Transmission Control
• Drive gently to avoid further damage until repaired.
• Avoid towing or heavy loads.
• Schedule a repair as soon as possible.
Check if your vehicle's powertrain warranty covers transmission components.
This code is relatively uncommon and often associated with specific transmission issues in certain models.
Moderate – Should be addressed soon to avoid transmission damage.
Driving with transmission issues can lead to further damage and potential safety hazards.
• Engine running
• Transmission in various gear positions
The pressure control solenoid is located inside the transmission, typically accessible by removing the transmission pan.
Q: Can I drive with a P27B8 code?
A: It's not recommended as it can cause further transmission damage.
Q: Will this code clear itself?
A: It may clear temporarily but will likely return if the underlying issue is not fixed.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.