W T E C I I I E L E C T R O N I C C O N T R O L S T R O U B L E S H O O T I N G M A N U A L
Figure 59. Code 25 Schematic Drawing
Main code 25 occurs if the output speed sensor reports a zero speed reading while both engine and turbine speeds
are approximately equal, turbine speed is above a calibration value, and neutral is not selected or commanded.
Main code 25 indicates either the output speed sensor has failed or the required oncoming clutch or clutches did not
come on. Code 2511 can be generated by a false turbine speed reading. This may be due to crosstalk between
solenoid and turbine speed sensor circuits caused by direct wire-to-wire short or by water in the electrical
connectors. See Section 4 for corrective action.
If code 25XX is in memory at ECU initialization (ignition on), all display segments are illuminated.
Active Indicator Clearing Procedure:
Before troubleshooting, read Paragraph 56. Also, check battery and ECU input voltages.
Intermittent connections or lack of battery-direct power and ground connections can cause this and
1. Check the transmission fluid level and ensure correct fluid level.
2. Check for the presence of code 2216. If code 2216 is in the code list, go to code 22XX section
and follow troubleshooting steps for code 2216.
3. Connect the Pro-Link® 9000 with ignition on, engine off; check for indication of turbine speed. If
turbine speed is indicated, refer to Paragraph 42 for corrective action.
4. If the output speed sensor and wiring are satisfactory, install pressure gauges into the appropriate
clutch pressure taps (see Appendix B in this manual) and make the shift again. See if either of the
clutches has low or no pressure. Lack of pressure in C1 in first range may be due to a G solenoid
stuck closed. Lack of pressure in C5 in first range may be due to an E solenoid stuck closed.
5. If a clutch is leaking pressure, drain the fluid, remove the control module and check for damaged
valve body gaskets and stuck or sticky valves. If no problems are found, replace the solenoids for
the clutches used in the range indicated by the code (refer to Figure 51). Refer to the appropriate
transmission Service Manual for replacement procedure.
Output speed sensor, detected at zero speed, Low range
Output speed sensor, detected at zero speed, 1st range
Output speed sensor, detected at zero speed, 2nd range
Output speed sensor, detected at zero speed, 3rd range
Output speed sensor, detected at zero speed, 4th range
Output speed sensor, detected at zero speed, 5th range
Output speed sensor, detected at zero speed, 6th range
Output speed sensor, detected at zero speed, Reverse
CODE 25 XX OUTPUT SPEED SENSOR, DETECTED AT ZERO SPEED,
X RANGE (Figure 59)