Transmission Control System

CODE NUMBER
Scan tool: 24
General scan tool: P1784

CODE NAME
Pressure switch circuit: LR

CODE DESCRIPTION
Technical Description
The transmission system uses three pressure switches to monitor the fluid pressure in the L-R element. The pressure switches are continuously monitored for the correct states in each gear.
(R, 2nd, 3rd, 4th: Open/P, N, 1st: Close)

Check Area
Whenever the engine is running.

Set Conditions
This code is set if the L-R pressure switch is open or closed at the wrong time in a given gear.

Transmission Effects
If a set condition is identified, 1st gear and torque converter lock-up (EMCC) will be inhibited. The vehicle will launch in 2nd gear and shift normally through the gears without allowing EMCC. If during the same key start, the set condition is no longer valid, the transmission will return to normal operation (1st and EMCC available). A relay open limp-in will not occur unless code 24 is accompanied by a code 28.

PROBABLE CAUSE
- If code 35 is present, ignore code 24 and perform code 35 diagnostic procedures
- L-R pressure switch sense circuit open or shorted to ground between TCM and solenoid pack
- L-R pressure switch sense circuit shorted to battery
- Solenoid pack
- Valve body-solenoid switch valve stuck. (May be accompanied by a code 37)
- Loose valve body bolts
- Plugged filter-internal transmission or torque converter failure
- Defective TCM





DIAGNOSTIC CHART