P0771 code definition
The P0771 code signifies that the car’s computer has detected a problem with shift solenoid E.
What the P0771 code means
A P0771 code means that there is a problem with the shift solenoid E in the automatic transmission. Your car’s transmission uses solenoids to automatically adjust the flow of transmission fluid to match driving needs and ensure smooth shifting. The problem can be due to electrical issues with the solenoid, or it could be contamination of the solenoid itself causing it to stick.
What causes the P0771 code?
Code P0771 can be caused by many different factors, including the following:
- Low transmission fluid
- Dirty/contaminated transmission fluid
- Faulty shift solenoid E
- Short or open in the wiring harness for shift solenoid E
- Blockage within shift solenoid E
- Faulty transmission control module (rare)
What are the symptoms of the P0771 code?
You may experience a number of different symptoms with code P0771, including the following:
- Harsh shifting
- Failure to shift
- Overheating of the transmission
- Check Engine Light or Transmission light on
- Reduced fuel economy
- Transmission stuck in “limp home” mode
How does a mechanic diagnose the P0771 code?
First, a mechanic will use an OBD II scanner to pull any codes from the car’s computer. Often, there are additional codes stored as well as the P0771 code. These can provide further guidance for the mechanic to determine the underlying problem.
The mechanic will also check the level and color of the transmission fluid to determine if the fluid is low, dirty or contaminated. This can also provide valuable guidance for further diagnostics, as well as determining the underlying cause of the trouble code.
If the fluid smells burnt or is very dark, the mechanic may pull the transmission fluid pan and inspect the fluid as well as the transmission for signs of damage from debris, such as clutch material. If no debris is found, the mechanic will then inspect the wiring harness and connection to shift solenoid E and replace any damaged wires, or clean corrosion and tighten connections.
The mechanic will also top off the transmission fluid (or change it completely in the case that it is dirty), and then clear the codes. The vehicle will be test driven for operation as well as to see if the code resets. Freeze frame data stored in the computer will also be used.
The shift solenoid E may also need to be tested mechanically and electrically. If it fails these tests, it will need to be replaced. The entire shift solenoid circuit should also be tested.
Common mistakes when diagnosing the P0771 code
The most common mistake is replacing shift solenoid E without first testing the shift solenoid circuit. Often, a malfunction with the circuit due to wiring damage or loose connections is the actual cause, rather than failure of the solenoid. Debris clogging the solenoid is also a common culprit.
How serious is the P0771 code?
The P0771 code is serious, as it will affect whether the vehicle can be safely driven. If the transmission fluid is contaminated, further driving can cause damage to other system components, as well. Repair this problem as soon as possible.
What repairs can fix the P0771 code?
In most instances, repairs to the shift solenoid wiring harness will fix the P0771 code, although replacing a faulty or clogged solenoid is also common. Adhering to the specified transmission service schedule can help to mitigate the risk of debris clogging the solenoid.
Additional comments for consideration regarding the P0771 code
While it can be tempting to assume that the problem is the solenoid, mechanics should not forget that the circuit can play a significant role here, and should be tested before parts are replaced.
Need help with a P0771 code?
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