P0778
PPowertrainPressure Control Solenoid B Electrical Fault
What does this code mean?
Severity : HighP0778 reports an electrical fault in the circuit of automatic transmission pressure control solenoid "B". This solenoid regulates the hydraulic pressure that applies the internal clutches during shifts. An electrical fault upsets this pressure and the gearbox often goes into limp mode.
Symptoms
- Check engine or transmission warning light on.
- Harsh shifts or slipping.
- Gearbox stuck in one gear.
- Difficulty pulling away on a slope.
Possible causes
- Faulty pressure control solenoid B.
- Damaged transmission wiring or connector.
- Damaged internal transmission harness.
- Degraded fluid or incorrect fluid level.
- Faulty transmission control module, less commonly.
Diagnosis and repair
- Check transmission fluid level and condition.
- Inspect the transmission connector and external wiring.
- Measure solenoid B resistance and continuity to the control module.
- Replace the solenoid or internal harness if needed.
- Clear the code, run transmission adaptations and road test.
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Code
P0778
Category
Powertrain
Prefix
P
Standard
OBD-II / SAE J2012