P0502

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 vehicle speed 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 a low vehicle speed when the vehicle has a large engine speed in a drive gear range, DTC P0502 sets. DTC P0502 is a type B DTC.

DTC PARAMETERS
DTC P0502 will set if:
^ TOSS signal is less than 100 rpm for 6 seconds.
^ Gear selector is not Park/Neutral
^ TPS greater than 15%
^ No TPS, TISS, TFP, P0503, or P1810 codes
^ No engine torque codes
^ Engine torque is greater than 54 N.m
^ Transaxle is in drive range
^ MAP is greater than 50 kPa
^ Input speed is greater than 1,000 RPM

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.