Transmission Control System

CODE NUMBER
Scan tool: 38
General scan tool: P0740

CODE NAME
Lockup control out of range

CODE DESCRIPTION
Technical Description
When in 2nd, 3rd, or 4th gear, the Torque Converter Clutch (TCC) can be locked when certain conditions are met. The TCC piston is electronically modulated by increasing the duty cycle of the L-R/TCC solenoid until the torque converter slip difference (difference between engine and turbine speed) is within 60 r/min, Then the L-R/TCC solenoid is fully energized (FEMCC = 100% duty cycle) torque converter slip is monitored in FEMCC to ensure adequate clutch capacity. The code will be set if one of these event's happen three times at a throttle angle less than 30 degrees.

Check Area
During Partial Electronically Modulated Converter Clutch (PEMCC) operation (also during FEMCC).

Set Conditions:
a) The transmission must be in PEMCC, with the input speed greater than 1750 r/min. The TCC/L-R solenoid must achieve it's maximum duty cycle and still not be able to pull the engine speed within 60 r/min of input speed.
b) If the transmission is in FEMCC and the engine can slip the TCC by more than 100 r/min (engine speed - Input speed) for 10 seconds.

Transmission Effects
EMCC will still be available after code is set. MIL will illuminate after 5 minutes of accumulated limp in FEMCC. The transmission will attempt normal operation (no-limp-in) even after the MIL is illuminated.

PROBABLE CAUSE
- Low/high fluid level in transaxle
- Worn pump bushing and/or failed torque converter- both should be replaced during a rebuild with code 38 present.
- Valve body-lock-up accumulator diameter out of spec. Possible, but not likely.





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