P0779 — Pressure Control Solenoid “B” Intermittent #

Note: The code description may vary depending on the vehicle manufacturer.

• P0779 – Pressure Control Solenoid “B” Intermittent (Generic/SAE)
• P0779 – Shift Solenoid B Intermittent (Honda)
• P0779 – Pressure Control Solenoid B Performance/Intermittent (GM, Ford, Toyota)
• P0779 – Solenoïde de pression B intermittente (Renault, Peugeot – French translation)

Summary for DTC P0779 #

P0779 is a diagnostic trouble code (DTC) indicating an intermittent issue with the Pressure Control Solenoid “B” in an automatic transmission. The pressure control solenoid is an electronically controlled valve that manages fluid pressure within the transmission to enable smooth gear shifts. When the Engine Control Module (ECM) or Transmission Control Module (TCM) detects an irregular or erratic electrical signal from this solenoid, it sets code P0779. This can result in unpredictable shifting, and in some cases, the transmission may enter a “limp” or “fail-safe” mode to prevent further damage. This code doesn’t usually point to a catastrophic failure, but it should be diagnosed and repaired promptly to avoid long-term transmission problems.

Common Symptoms for DTC P0779 #

When code P0779 is present, your vehicle may display a range of symptoms, mostly related to transmission performance. Some issues may be subtle, while others can make the vehicle difficult or unsafe to drive. Here are the most frequent warning signs:

• Harsh or delayed gear shifts, especially when accelerating or decelerating
• Transmission slipping (engine revs increase but vehicle speed does not)
• Failure to shift into certain gears or “stuck” in a single gear (limp mode)
• Transmission warning light or Check Engine Light (CEL) illuminated
• Erratic or unpredictable shifting behavior
• Reduced fuel economy in some cases

Most Likely Causes for DTC P0779 #

Several potential issues can trigger code P0779, but some are more common than others. In most cases, the problem lies within the transmission’s hydraulic or electrical systems. Here are the most frequent causes, listed in order of likelihood:

1. Faulty pressure control solenoid “B” (internal electrical or mechanical failure)
2. Contaminated, degraded, or incorrect transmission fluid
3. Wiring problems (damaged wires, corroded connectors, or loose terminals in the solenoid circuit)
4. Faulty transmission control module (TCM) or engine control module (ECM)
5. Internal transmission mechanical issues (e.g., sticking valves, excessive debris in valve body)
6. Poor ground or power supply to the solenoid or control module

Step-by-Step Diagnostic for DTC P0779 #

Accurate diagnosis of P0779 requires a methodical approach to avoid unnecessary repairs. Here’s how a professional technician or a knowledgeable DIYer should proceed:

• 1. Scan for additional codes: Check for other transmission or electrical DTCs that could provide more context.
• 2. Inspect transmission fluid: Check fluid level, color, and smell. Dirty or burnt fluid may indicate internal problems.
• 3. Inspect wiring and connectors: Look for damaged, corroded, or loose connections at the pressure control solenoid “B” and related harnesses.
• 4. Test solenoid operation: Using a scan tool, perform an actuation test on solenoid “B” if available. If not, measure solenoid resistance with a multimeter and compare with OEM specs.
• 5. Check power and ground: Verify correct voltage and ground at the solenoid’s harness connector.
• 6. Inspect valve body (if accessible): Look for signs of debris, sticking valves, or internal damage.
• 7. Test or substitute control module: If all else checks out, consider the possibility of a faulty TCM/ECM.

Possible Repairs for DTC P0779 #

The required repair depends on the root cause found during diagnosis. Here are the most common solutions, matched to their likely cause:

• Replace faulty pressure control solenoid “B” if electrical or mechanical failure is confirmed
• Flush and replace transmission fluid if it’s dirty, burnt, or the wrong type
• Repair or replace damaged wiring/connectors in the solenoid circuit
• Repair or replace faulty TCM/ECM if confirmed defective after all other checks
• Clean or rebuild valve body if internal sticking or debris is found
• Address any internal transmission damage as necessary (may require rebuild in severe cases)

Can You Drive with Code P0779? #

Limited — Caution advised. While some vehicles may continue to operate with reduced performance, driving with code P0779 can lead to further transmission damage or leave you stranded if the shift solenoid fails completely. If you notice harsh shifting, slipping, or are stuck in one gear, it’s safest to have the vehicle inspected and repaired as soon as possible. Prolonged driving may increase repair costs and risks.

Vehicles Most Commonly Affected by DTC P0779 #

While P0779 is a generic code found in many modern vehicles with automatic transmissions, it’s more frequently reported in certain makes and models. The issue often appears in vehicles from the early 2000s onward, especially those using electronically controlled transmissions.

• Honda Accord, Odyssey, Pilot (2002–2012)
• Toyota Camry, Corolla, Highlander (2001–2016)
• Ford Fusion, Escape, Focus (2005–2017)
• GM Chevrolet Malibu, Impala, Equinox (2004–2015)
• Nissan Altima, Maxima (2005–2017)
• Chrysler Town & Country, Dodge Caravan (2001–2014)

Common Mistakes & Best Practices for DTC P0779 #

Misdiagnosis is common with P0779 due to its intermittent nature. To avoid unnecessary repairs, keep these tips in mind:

• Don’t replace the transmission or control module before testing the solenoid and wiring thoroughly.
• Always inspect and change the transmission fluid if it’s dirty or burnt; old fluid can mimic electrical faults.
• Double-check connector tightness and corrosion — intermittent codes are often due to poor contact.
• Use OEM or high-quality replacement parts for solenoids and connectors to ensure durability.
• Clear the code and re-test after repair to verify the fix.

Quick FAQ for DTC P0779 #

Q: Will clearing the code fix the problem?
A: No. Clearing the code without addressing the root cause will only make the warning disappear temporarily. The code will return as soon as the issue reappears.

Q: Is it expensive to fix P0779?
A: It depends. If the issue is only with the solenoid or wiring, repairs are often affordable. If internal transmission damage is present, costs can rise significantly.