P0776 Fault Code

Long Description

Fault code P0776 is logged when the primary onboard computer, the powertrain control module (PCM), has detected a malfunction with the shift solenoid “B” pressure control circuit.

This happens when the PCM has detected that the pressure control solenoid B is not performing properly and is likely stuck off, causing solenoid B to malfunction.

Shift solenoids are responsible for allowing an automatic transmission to shift up or down without the use of a clutch input from the driver. This is done by using transmission fluid and hydraulic circuits.

This code is obviously limited to vehicles with automatic transmissions as the driver plays the role of the PCM in this instance with a manual transmission.

Nissan is by far the most commonly searched manufacturer alongside this fault code. Mitsubishi and Toyota are also fairly regularly associated with this issue.

Other Signs of This Problem

Because of the importance of the shift solenoids, there can be some significant changes in driveability when there is an issue like this.

The most obvious sign will be that the Check Engine light will illuminate.

Other signs will be related to the improper operation of the automatic transmission.

These can be things like gear slipping, overheating, and being stuck in a certain gear.

In some cases, the vehicle may enter limp mode as it cannot properly change into the appropriate gear.

There may also be other shift solenoid codes like P0745, P0755, and P0779.

What Could Be The Problem?

The shift solenoids operate through both transmission fluid and electronics, meaning the cause for this issue can be found within either the transmission fluid system or the pressure solenoid control circuit.

Clogging in the transmission fluid lines can cause this fault code. Additionally, a defective or clogged transmission fluid filter can prevent sufficient pressure.

It is also possible that there is insufficient transmission fluid.

This can also be caused by a defective transmission fluid pump as it cannot supply enough pressure for the shift solenoid to open or close correctly.

Faults like damaged wiring or a loose connection within the solenoid circuit are other potential causes. Additionally, a faulty control solenoid B can cause this fault code.

Hydraulic passages that are restricted or clogged can prevent the solenoid from functioning properly.

Fixes

Fixes should focus on the pressure control solenoid B circuit before addressing potential issues within the transmission fluid system.

The solenoid B circuit should be checked. Loose connections or damaged wires need to be fixed. A faulty solenoid should be replaced.

If there are no issues with the pressure control solenoid B circuit, the transmission fluid system needs to be checked.

A defective transmission fluid filter must be replaced. Transmission fuel should be replaced if it is too low due to a leak or damage.

Any restrictions in the hydraulic fluid lines need to be fixed to allow for proper flow.

Seriousness

Fault code P0776 should be considered a serious issue. It can completely hamper the driveability of a vehicle as the automatic transmission cannot function properly.

It is a good idea to have this issue fixed immediately to restore the proper operation of the vehicle.