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
3. If fluid and wiring are satisfactory, install a pressure gauge in the pressure tap for the offgoing
clutch. Make the shift indicated by the subcode using the clutch test mode of the Pro-Link®
diagnostic tool. If the pressure gauge shows clutch pressure (above 55 kPa or 8 psi) remains in the
offgoing clutch, drain the fluid and remove the control module (see the transmission Service
Manual). Disassemble and clean the control module and check for damaged valve body gaskets
and stuck or sticky valves, particularly latch valves and solenoid second-stage valves.
4. If excessive clutch pressure is not remaining in the offgoing clutch, replace the engine speed
sensor and the turbine speed sensor.
5. If the control module is removed to replace the turbine speed sensor (MD, B 300, B 400), clean the
control module and inspect for stuck or sticky valves (particularly the latch valves and solenoid G
second stage valve). Check the rotating clutch drum to which the turbine speed sensor is directed
for damage, contamination, or signs of contact between the drum and the sensor.
6. If the problem recurs, replace the solenoid(s) for the offgoing clutch(es).
7. If the problem again recurs, the offgoing clutch must be held on mechanically (coned, burned,
etc.). Remove the transmission and repair or rebuild as necessary.
8. 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.
CODE 53 XX OFFGOING SPEED TEST (DURING SHIFT)