P0777 Pressure control solenoid B stuck on

Pressure control solenoid B stuck on

P0777 in short

P0777 means pressure control solenoid B appears stuck on, so the transmission is not getting the pressure the computer commands. Dirty fluid or debris in the valve body is a common cause, and GM has bulletins for its trucks. It can cause harsh shifts, slipping or no forward drive; have it inspected soon.

Pressure control solenoids set the fluid pressure that applies the clutches. P0777 sets when the computer sees that solenoid B is not releasing as commanded, as if it were stuck on, so clutch pressure is wrong.

GM bulletins tell technicians to look for debris in the valve body with pressure solenoid codes on 2010–2011 trucks, and say a history-only P0777 on some 2016 Silverado and Sierra 1500 trucks needs no repair while a calibration is prepared. Some GM vehicles lose forward drive with P0777.

Shifts may be harsh or erratic, the transmission may slip or stay in one gear, and it may overheat.

Most likely causes

  1. Dirty fluid or debris in the valve body

    Common general cause
    Why it ranks here
    A code reference lists low or dirty fluid and blocked passages, and GM tells technicians to check the valve body for debris with this code.
    What would change this
    Rises if the fluid is dark, burnt or has particles.

  2. Faulty pressure control solenoid B or wiring

    Common general cause
    Why it ranks here
    The solenoid is the monitored part, and a code reference lists the solenoid and wiring.
    What would change this
    Rises if the solenoid or circuit fails a test.

  3. Software calibration (2016 GM 1500 trucks)

    Supported by vehicle data
    Why it ranks here
    GM says a history-only P0777 on 2016 Silverado and Sierra 1500 needs no repair and a new calibration is coming.
    What would change this
    Rises if P0777 is history only on a covered truck.
    How to test the transmission control module (tcm)

  4. Internal clutch or valve fault (some GM)

    Supported by vehicle data
    Why it ranks here
    GM bulletins cover no forward movement, slipping or binding with P0777 on several models.
    What would change this
    Rises if the vehicle will not move forward or slips in drive.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read codes from the engine and transmission modules with a scan tool that supports both, before anything is cleared.

    Low riskTool: scan tool that reads the transmission module

  2. Check for a P0777 bulletin for your VIN at a dealer or on the NHTSA site.

    Low risk

  3. Have a shop check fluid condition, test the solenoid circuit and inspect the valve body if needed.

    Best left to a shopTool: scan tool with transmission output controls

    Warning:Shop test. It needs the maker's procedure.

Symptoms

  • Check engine light
  • Harsh or erratic shifts
  • Slipping or no forward movement Gets more serious: stop and have it checked.
  • Transmission stuck in one gear (limp-home mode) Gets more serious: stop and have it checked.

How to fix

  1. Do not clear the code before the transmission module has been read; GM treats current and history P0777 differently.

  2. Ask a dealer whether your VIN has an open P0777 bulletin. GM has issued several.

Parts and cost context

  • Transmission control module (TCM):GM asks technicians to check the transmission computer date code with pressure solenoid codes on some 2010–2011 trucks, but fluid and the valve body come first.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Chevrolet

  • 2016 · Silverado 1500

    Supported by vehicle data

    GM PIP-5396 says do not repair when P0777 is only a history code; a new calibration was planned. The Sierra 1500 is also covered. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

  • PIP4831EStatus unverified

    Pressure solenoid codes: look for valve body debris

    2010–2011silverado-2500 · issued · NHTSA 10154593

    Covers several pressure solenoid codes including P0777; look for debris in the valve body and review the TCM date code. Only the NHTSA flat-file summary was read, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • PIP-5396Status unverified

    P0777 history code: no repair, calibration coming

    2016silverado-1500 · issued · NHTSA 10078870

    If P0777 is current, follow normal diagnosis; if history only, do not repair. Also lists the Sierra 1500. Only the NHTSA flat-file summary was read, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

GMC

  • 2015 · Canyon

    Supported by vehicle data

    GM PI1419 gives diagnostic tips for no forward movement with P0777 or P2723. The Colorado is also covered. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

  • PI1419Status unverified

    No forward movement with P0777 or P2723

    2015canyon · issued · NHTSA 10113555

    Diagnostic tips for no forward movement. Also lists the Colorado. Only the NHTSA flat-file summary was read, not the bulletin itself.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0700Transmission module requests the check engine light

    Primary / secondary Possible — needs testing

    Likely primary: P0777. On cars with a separate transmission module, a basic code reader may show only P0700, which means the module has stored its own code. P0777 can be that code, so fix P0777 and P0700 goes with it.

  • P0776Pressure control solenoid B not working as expected or stuck off

    Same system Possible — needs testing

    P0776 is the stuck-off or performance code for the same solenoid B. GM lists both with valve body debris.

  • P2714Pressure control solenoid D is not working or stuck off

    Same system Possible — needs testing

    P2714 is the matching performance code for pressure control solenoid D, also in the GM debris bulletin.

All Transmission codes

P0777 questions

What is the difference between P0776 and P0777?

Both are for pressure control solenoid B. P0776 means it appears stuck off or not performing, P0777 that it appears stuck on.

Sources and review

  1. Toyota Camry Owner's Manual (OM06291U) — Toyota
  2. P0777 OBD-II Trouble Code: Pressure Control Solenoid B Stuck On — Kelley Blue Book
  3. GM PI1419: No forward movement with P0777 or P2723 — General Motors / NHTSA ,
  4. GM 3996: No movement, slipping or binding in forward — General Motors / NHTSA
  5. Cal. Code Regs. Tit. 13, § 1968.2 — Malfunction and Diagnostic System Requirements (OBD II) — California Air Resources Board (via Cornell LII)
  6. GM PIP4831E: Pressure control solenoid codes: look for valve body debris — General Motors / NHTSA ,
  7. GM PIP-5396: P0777 history code: no repair, calibration coming — General Motors / NHTSA ,
  8. DTC P0700 — Saab 9-5 (9650) 2010 Workshop Information System — SaabWISOnline (community rehost of Saab/GM service information)
Last reviewed
Written by
Saurabh K.
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