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Home >> Chevrolet >> 2018 >> Spark LT, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 56 (Automatic Transmission - JATCO CVT) >> Diagnostic Information and Procedures >> DTC P0961-P0963, P0965-P0967, P0970, P0971, P2720, P2721, P2763 or P2764: Control Solenoid Valve (MR8) >> Circuit/System Description

Circuit/System Description

WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.

For an overview of the component/system, refer to Electronic Component Description  Enter Cell-Link

Circuit Description
Control Regulated voltage supplied by the control module. Supplied from a fuse.
Component Description
Q8 Control Solenoid Valve Assembly A matrix of PWM solenoids and valves that control what gear the transmission is in.
K71 Transmission Control Module An electronic control module used to control the transmission.
Q77 Transmission Control Solenoid Valve - 1, 2, 3, 4, 5 Part of the Q8 Control Solenoid Valve Assembly A solenoid valve is an electro-mechanically operated valve. The valve is controlled by a pulse width modulated electric current through the solenoid used to control hydraulic pressure.

The pressure control solenoid valves are part of the control solenoid valve assembly which has no serviceable parts.

The K71 Transmission Control Module connects to the Q77 Transmission Control Solenoid Valves thorough the Q8 Control Solenoid Valve Assembly connector.

The transmission control module controls the pressure that the pressure control solenoids supply by regulating the current flow through the pressure control solenoid valve windings. The transmission control module determines the appropriate pressure for a given load by monitoring the throttle position sensor voltage, the engine speed and other inputs. The transmission control module then varies the duty cycle on the high side of the pressure control solenoid valve to control current flow to the solenoid. The magnetic field produced by the coil moves the solenoids internal valve which varies pressure to the pressure regulator valve. The transmission control module controls the pressure control solenoid valve by applying a varying amount of amperage to the solenoid. Current is controlled from about 20 mA for minimum line pressure to 1200 mA for maximum pressure. The transmission control module monitors the actual current to the solenoid as compared to the requested current.