P0779: Pressure Control Solenoid B Intermittent

Pressure control solenoids are current-controlled proportional valves, and what B and C mean depends on the design: on GM's clutch-to-clutch automatics they are the pressure valves of clutches 2 and 3, on GM's CVT B is primary pulley pressure and C line pressure, on Jatco CVTs B is the secondary pressure valve, on Saab's AF40 B and C are clutch valves SLC1/SLC2. In J2012 P0779 is an intermittent fault of valve B. The only manufacturer use found differs: Mitsubishi's 2022 Jatco CVT sets P0779 for an open circuit or short to positive in the secondary pressure valve circuit after 1 s (short to ground is P0778). The transmission then engages harshly, accelerates weakly and does not lock up.

Symptoms

• Harsh engagement at times
• Weak acceleration, no lock-up
• Check engine light

Most likely causes

• Connector or wire open or loose contact
• Short to positive in the harness
• Valve coil faulty

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the fluid level and condition according to the manufacturer
2. Gently move the wiring with the engine running and watch whether the reading changes.
3. Check the transmission connector
4. Read the data with a transmission-compatible scanner
5. Measure the solenoid valve circuit
6. Leave opening the transmission to a specialized repair shop

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P0779 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 7: Transmission
• 79: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0779?

Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.

What causes code P0779?

The most common causes are: connector or wire open or loose contact; short to positive in the harness; valve coil faulty.

Related codes

• P0778Pressure Control Solenoid B Electrical
• P0776Pressure Control Solenoid B Performance/Stuck Off
• P0966Pressure Control Solenoid B Control Circuit Low
• P0967Pressure Control Solenoid B Control Circuit High
• P0965Pressure Control Solenoid B Control Circuit Range/Performance

Sources

• mitsubishitechinfo.com: N5040201C0009700USA
• mitsubishitechinfo.com: N5040201F0000500USA
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.