P0775 code definition
The P0775 code identifies a problem with a solenoid located within an automatic transmission.
What the P0775 code means
The P0775 code is the OBD-II generic code for insufficient fluid pressure within a solenoid operating the automatic transmission. When the P0775 code is indicated, then that means that a hydraulic solenoid in the transmission is not experiencing the proper amount of pressure from the hydraulic fluid. These solenoids are responsible for moving the transmission into gear and controlling the torque converter. Insufficient fluid pressure means that the solenoids may not be able to operate correctly.
What causes the P0775 code?
The insufficient solenoid pressure code may have several causes:
- Leaks or blockages in fluid pathways within the transmission
- Malfunctioning electronic pressure control solenoid
- Low or dirty transmission fluid
- Electrical problem with transmission control module
- Electrical problem with powertrain control module
- Mechanical issue within the transmission
What are the symptoms of the P0775 code?
The P0775 code has most directly to do with the transmission. Because of this, symptoms that coincide with the P0775 code involve transmission performance. In some vehicles, this code will cause the transmission to go into “limp” mode, slowing and reducing transmission function. Shifting will become rougher and less regular. The transmission will likely slip gears as well, and stands a higher chance of overheating. All of this will likely reduce fuel economy noticeably.
In some applications, this code must persist for a while before the Check Engine Light will illuminate on the dashboard.
How does a mechanic diagnose the P0775 code?
Before doing any significant diagnostic work, the technician will check the transmission fluid levels while also checking the fluid quality. If there is low or dirty fluid in the transmission, it is likely the cause of the P0775 code.
After the fluid is checked, a certified technician will use an OBD-II scanner to view the trouble code in real-time to see when it was first indicated. Then the code will be reset before the technician takes the vehicle for a test drive. If the code appears again during the course of the test drive, then it will confirm that the original code was not the result of an electrical short or issue that occurs intermittently.
Once the code appears again, the wiring and circuitry around the transmission control module and the powertrain control module will be inspected for damage or disconnections. The circuitry will then be tested by a technician with a voltmeter.
Common mistakes when diagnosing the P0775 code
Parts like the high pressure pump, electronic pressure control solenoid, and the wiring harness are often replaced unnecessarily when this error code appears. Often, the problem arises due to poor quality or insufficient quality regarding the transmission fluid. Small, intermittent electrical issues can also cause this code to appear, so it is wise to do a full diagnosis of the issue when the P0775 code appears.
How serious is the P0775 code?
The P0775 code has the potential to significantly hinder vehicle performance via the transmission. If the transmission enters “limp” mode or if the issues within the transmission prevent proper operation, then the fuel economy and overall performance will suffer. For these reasons, the P0775 code is serious enough that it should be diagnosed immediately.
What repairs can fix the P0775 code?
The most common repairs to address the P0775 are as follows:
- Repair or replace damaged wiring harness
- Repair or replace damaged or corroded circuitry
- Rebuild or replace transmission
- Replace or add transmission fluid
- Repair or replace high pressure pump
- Repair or replace electronic pressure control solenoid
Additional comments for consideration regarding the P0775 code
Codes for the torque converter clutch, shift solenoid, gear ratios, and transmission slippage often accompany the P0775 code. The amount of pressure that is needed within the solenoids controlling the transmission is determined by throttle position, engine speed, and several other metrics that are calculated together to determine the the correct gear and amount of torque converter lockup.
Need help with a P0775 code?
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