CODE 25 XX -- OUTPUT SPEED SENSOR, DETECTED AT ZERO SPEED, X RANGE

WTEC III ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL

CODE 25 XX -- OUTPUT SPEED SENSOR, DETECTED AT ZERO SPEED,

X RANGE (Figure 59)

6. If, after detecting leaking pressure and replacing solenoids, the problem persists, check for worn

clutch or piston seals. Remove the transmission and repair or replace as necessary.

7. This code requires accurate output and turbine speed readings. If there were no transmission prob-

lems detected, use the diagnostic tool and watch the speed readings for noise (erratic signals) from

low speed to high speed in the range indicated by the code.

8. If a noisy sensor is found, check the sensor resistance (refer to the sensor resistance chart below)

and check its wiring for opens, shorts, and shorts-to-ground (see code 22 XX). Also closely check

the terminals in the connectors for corrosion, contamination, or damage. Ensure the wiring to the

sensors is a properly twisted wire pair. Remove sensor and check for damage at the tone wheel

end. Check for looseness of the tone wheel. Replace the sensor if it is damaged or if its resistance

(refer to Service Manual for proper procedure) is incorrect and isolate and repair any noted wiring

problems. (Use St. Clair P/N 200153 Service Harness Twisted Pair for this procedure.)

Resistance

Temp. C

Temp. F

200

300

400

110

230

9. If no apparent cause for the code can be located, replace the turbine and output speed sensors.

Refer to the appropriate transmission Service Manual for proper procedure.

10. If the condition persists, replace the ECU. If replacing the ECU corrects the problem, reinstall the

original (bad) ECU to confirm that the problem is in the ECU. If the original ECU now works,

inspect the ECU connectors for any corrosion or damage which may cause an intermittent

condition. If the original problem recurs, reinstall the replacement ECU.

0021 0072