P1778 Volvo Auto Trouble Code on vehicles with electronically controlled automatic transmissions, the 3-4 shift solenoid is responsible for actuating the hydraulic circuits to activate clutches or bands that change gears inside the automatic transmission.
The computer notices the canister is empty when it detects a leaner condition (all the vapors are used up) and it resumes normal fuel delivery. Some car manufacturers then close the vent solenoid but leave the purge solenoid open. That creates a vacuum throughout the entire fuel storage system. Once the correct vacuum is reached, it closed the purge solenoid and waits to see if the vacuum holds.
Power Steering Pressure (PSP) Switch Signal Malfunction The PCM counts the number of times vehicle speed transitions from 0 to a calibratable speed. After a calibratable number of speed transitions the PCM expects that the PSP input should have changed. This DTC is set if the transition is not detected. Vehicle towed with engine running Power steering hydraulic concern was repaired but DTC was not erased PSP switch/shorting bar damaged SIG RTN circuit open PSP circuit open or shorted to SIGRTN PCM damaged Check, if possible, if vehicle was towed or power steering service was performed. Observe PSP V PID while checking wires for intermittents.
P1778 Volvo Trouble Repair :
When you turn on the ignition, the Service Engine Soon or Check Engine P1778 Volvo light should flash briefly, indicating that the OBD system is ready to scan your vehicle for any malfunctions. After this brief flash, the light should stay off while you drive as long as no problems are detected. You'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the car! |
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