1, 2 and 3 Digit Codes: 27

Name of Code:
27 Pressure Switch Circuit

When Monitored:
Whenever the engine is running.

Set Condition:
This code is set if the L-R and 2-4 and OD pressure switches are either open or closed at the wrong time in a given gear. (See chart below) This code indicates that all of the pressure switches indicated the wrong state at the time the fault was set.

Theory of Operation:
The Transmission system uses three pressure switches to monitor the fluid pressure in the L-R, 2-4, and OD elements. The pressure switches are continuously monitored for the correct states in each gear as shown below.

Transmission Effects:
- 89-95 MY + 96 MY V-I calibration - relay open limp-in mode.
- 96 MY V-2 calibration (default desensitization) and 97 MY - Code eliminated, codes 21, 22 and 24 will be set.

Possible Causes:
- If code 35 is present, ignore code 27 and perform code 35 diagnostic procedures.
- If code 35 is not set, follow diagnostic procedures for codes 21, 22 and 24.