2-3 Block-Out Relay

2nd - 3rd Block-Out Solenoid Circuit Diagram:

DESCRIPTION
The 1-4 upshift system requires the vehicle to be shifted from first gear to fourth gear under certain conditions. When in operation, the 2-3 block-out solenoid in the transmission prevents the linkage from engaging second and third gears. By shifting from 1st to 4th gear during specified engine conditions, fuel economy is increased.

OPERATION
The 1-4 upshift relay gets battery power when the ignition is turned "ON" and becomes energized when the PCM completes the circuit to ground. When energized, the relay supplies power to the 2-3 block-out solenoid in the transmission. The PCM uses engine speed, vehicle speed, throttle position and engine coolant temperature sensors to determine if the vehicle is within parameters to shift directly to fourth gear from first gear. The 1-4 upshift system operate only once per upshift cycle and will not re-enable until the vehicle speed drops below 1 mph. The PCM completes relay circuit under the following conditions:

^ Engine running
^ Vehicle speed greater than 12 mph but less than 19 mph
^ Throttle position less than 35%
^ BARO pressure greater than 76 kPa.
^ Engine coolant temperature greater than 50°C (122°F)


LOCATION
The 2-3 block-out relay is mounted on the rear of the right front wheel housing, nearest to the engine.