Aisin 81-40LE - Automatic Transmission (European Emissions)

DTC P0748 (European Emissions)

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0748 Pressure Control (PC) Solenoid Control Circuit

Conditions for Setting the DTC

* The transmission control module (TCM) detects that the ON signal of the lockup solenoid monitor during 0.5 seconds when lockup solenoid driver outputs the OFF signal. The torque converter clutch (TCC) circuit is open or short to battery.
* The TCM detects that the OFF signal of the lockup solenoid monitor during 0.3 seconds when lockup solenoid driver outputs the ON signal. The TCC circuit is short to battery.
* The above detection 8 times at shifting continuously

Action Taken When the DTC Sets

* TCM will request the illumination of the malfunction indicator lamp (MIL) and store the DTC when the TCM detects failures on 2 consecutive ignition cycles
* No TCC lockup solenoid
* 1st gear fixed under the 10 km/h

Conditions for Clearing the DTC

* The TCM turns off the MIL when no further failures are detected on the next ignition cycles.
* The scan tool can clear the DTC from the TCM history.
* The TCM clears the DTC from the TCM history memory after 40 consecutive ignition cycles without fault.
* The TCM detects the ON signal of the lockup solenoid monitor during 160 ms when the lockup solenoid driver outputs the ON signal and the TCM detects the OFF signal of the lockup solenoid monitor during 160 ms when lockup solenoid driver outputs the OFF signal.

Cause of Failure

* Wiring harness or connector between lockup solenoid and TCM
* Lockup solenoid
* TCM