Express Up operation of the front door power windows is monitored and controlled by the front door modules and the window sensors. Each front door window motor has a window sensor mounted to it. The driver door module (DDM) and the passenger front door module (PDM) each supply battery voltage and ground to power their respective window sensors. The door modules and sensors communicate with each other via a power window high speed serial data circuit, and a power window low speed serial data circuit. The window sensor detects differences in the window motors electrical pulses to determine if there is an obstruction to the travel of the window glass. The door modules use the information generated by the sensors to disable the Express Up movement of a window, or reverse the direction of travel, in the event that a passenger, or other obstacle, has become trapped in it.

The power window high speed serial data circuit is a unique one-way communications link between the sensor and the door module. The sensor uses a voltage signal, and also a 1 kHz signal, to transmit information, via this circuit, from the sensor to the door module.

This diagnostic procedure supports the following DTCs:

The door module must be powered and can not have B1327-Battery Voltage Low or B1328-Battery Voltage High set for this DTC to set.

The DTC will be set by the DDM or the PFDM when the DDM or PFDM detects either of the following conditions:

The DDM or PDM will not allow the Express Up function for that window to operate. All other window functions for that window will still operate.

The DDM or PFDM will clear the current DTC when either of the following occurs:

DTC U1713 may indicate a failure of the power window high speed serial data circuit, however, if DTC U1713 is set only in history and there is no complaint or failure symptom present, clearing the DTC should be the only action necessary. Some vehicles may set DTC U1713 erroneously if a window is operated in one express direction, then suddenly reversed to the opposite express direction. This can occur when the window express direction is quickly reversed by the operator, or during a window reversal triggered by an object becoming trapped between the window glass and window frame. DTC U1713 can be permanently concealed from the affected door module using the scan tool masking capability. With the scan tool, the DTC Mask screen is accessed from the Special Functions, Set Options screen of the door module. The on-screen instructions explain how to mask the DTC.