P0503

Diagnostic Chart:

Schematic:

The Transaxle Output Speed Sensor (TOSS) is a Permanent Magnet (PM) generator mounted to the transaxle case. The PM generator produces an AC voltage as the transaxle speed sensor rotor teeth pass through the sensor's magnetic field. The AC voltage level increases as the speed of the vehicle increases. The Transaxle Control Module (TCM) converts the AC voltage into a digital signal. The TCM uses the vehicle speed signal to determine shift timing, Torque Converter Clutch (TCC) apply, TCC release, and gear ratio calculations.

When the TCM detects an intermittent loss of vehicle speed when the vehicle has a large engine speed in a drive gear range, DTC P0503 sets. DTC P0503 is a type B DTC.

DTC PARAMETERS
DTC P0503 will set if:
^ Drop in output speed is greater than 1800 rpm in Drive ranges
^ Gear selector is not Park/Neutral
^ TPS greater than 15%
^ No TISS or TFP codes
^ Time since last manual range change greater than 6 seconds
^ Engine speed greater than 500 RPM for 5 seconds and not at fuel cutoff

IMPORTANT: The TOSS signal is continuously checked once the above conditions are met. If TOSS signal is missing, the speedometer will be inoperative.

DIAGNOSTIC AIDS
^ The TCM will calculate vehicle speed based on engine speed, input shaft speed, and commanded gear, but the speedometer will remain inoperative.
^ TOSS resistance = 1530-1870 ohms.
^ If problem is intermittent wiggle wires while monitoring TOSS signal on Scan tool and watch for loss or change in signal.