P0777

Code

LAND ROVER P — Powertrain

Pressure Control Solenoid B - stuck in

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 18 EN: 50 RU: 39

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Page language: EN

Causes

Faulty Pressure Control Solenoid B (stuck mechanically or electrically)
Contaminated, dirty or low transmission fluid restricting solenoid/valve movement
Valve body internal sticking or debris
Open, short or high resistance in solenoid wiring or connectors
Poor ground or 12V supply to the solenoid
Faulty Transmission Control Module (TCM) or PCM software/driver

Symptoms

Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
Harsh, delayed, or erratic shifting; transmission may fail to shift properly
Transmission stuck in a gear (often limp-in mode)
Poor drivability and reduced fuel economy
Unusual transmission noise or shudder
Stored transmission-related trouble codes and possible limp-home strategy

What to check

Read and record all stored codes and freeze frame data with a capable scan tool
Check transmission fluid level and condition (color, smell, debris). Refill/replace if contaminated
Visual inspection of solenoid connector and wiring for damage, corrosion or loose pins
Backprobe solenoid connector while commanding with a scan tool to verify supply and driver signals
Measure solenoid coil resistance and compare to manufacturer spec
Perform wiggle test on harness while monitoring for intermittent changes

Signal parameters

Supply voltage: battery/ignition 12 V (nominal) to solenoid supply pin when key on
Driver output: PWM duty cycle command from TCM, typically 0–100% (varies by model)
Command frequency: commonly tens to a few hundred Hz (varies by vehicle/TCM)
Expected coil resistance: typically in the low tens of ohms (manufacturer-specific; check spec)
Open-circuit: infinite/very high resistance; Short: near 0 Ω — both are fault conditions
When commanded, voltage at control pin will vary with duty cycle; when off, should be near 0 V or ground depending on driver type

Diagnostic algorithm

Retrieve P0777 and any related codes, note freeze frame and drive conditions.
Check transmission fluid level and condition. If fluid is low or heavily contaminated, correct level or replace fluid and filter before further testing.
Perform a careful visual inspection of the solenoid connector and wiring harness for damage, corrosion, bent pins or poor ground.
With ignition on (engine off), measure coil resistance at the solenoid connector. Compare to factory specification. Replace solenoid if out of spec.
Backprobe harness while commanding the solenoid with a scan tool. Verify proper supply voltage, ground and PWM signal. Observe changes as duty cycle is varied.
Wiggle the wiring and connector while monitoring the command and feedback for intermittent faults.
If electrical tests are good but solenoid does not actuate or transmission behavior is abnormal, remove and bench-test the solenoid and inspect valve body for contamination or stuck valves.
Clean or replace the solenoid and/or valve body as required. Replace filter and fluid if contaminated.
After repair, clear codes and perform a road test and re-scan to confirm the fault does not return. If fault persists with good solenoid and wiring, consider TCM/software or internal hydraulic issues and refer to manufacturer procedures.
If replacing TCM/PCM is considered, verify all wiring and mechanical components first and follow OEM programming and adaptation procedures.

Likely causes

Solenoid plunger mechanically stuck from contamination or wear
Clogged valve body passages or stuck shuttle valve
Connector corrosion, damaged pins, or broken wire causing intermittent or no control
Low/dirty transmission fluid causing sluggish solenoid response
Failed solenoid coil (open/short) or intermittent coil winding

Fault status

⚠️ Status

P0777 — Pressure Control Solenoid B stuck; TCM detected no expected movement or response from PCSB. May set MIL and enable limp mode until repaired.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.5 hours

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P0777 — Pressure Control Solenoid B - stuck in