DTC 73 - P1798

Name of Code:
P-1798(73) Deteriorated Transaxle Fluid

When Monitored: At every Fully Electronically Modulated Converted Clutch (FEMCC) to Partial Electronically Modulated Converter Clutch (PEMCC) transition miles when A/C compressor clutch is being cycled.

Set Condition: The code will be set if vehicle shudder is detected 20 times when the A/C clutch is cycled.

Theory of Operation: While in 3rd or 4th FEMCC and just before the A/C clutch engages, the Powertrain Control Module (PCM) requests the Transmission Control Module (TCM) to momentarily establish PEMCC operation. If vehicle shudder is detected during the FEMCC to PEMCC transition, a counter is incremented. If the count reaches 20, the trouble code is set. The driver may then notice harsh bumps when the A/C clutch is being cycled, but vehicle shudder will be eliminated. After 35 OBDII warm-up starts or if the code is cleared, PEMCC will be reactivated to see if shudder is still present. If one shudder event occurs, the code will be reset. Clearing the code and running battery disconnect with the DRBIII(R) is the only way to reset the shudder counter from 20 back to zero.

Transmission Effects: This code does not cause the transmission to go into limp-in mode. However, once the code is set, FEMCC to PEMCC operation before the A/C clutch engagement will be disabled for 35 OBDII warm up starts.

Possible Causes:
- Degraded transmission fluid
- Wheels severely out of alignment
- Internal torque converter problem