P0503

Diagnostic Chart:

Schematic:

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

When the PCM detects a loss of vehicle speed while the vehicle is in motion, then DTC P0503 sets.

DTC PARAMETERS
DTC P0503 will set if TOSS drops greater than 1200 rpm for 3 seconds when:
- Output speed drops greater than 1,200 RPM for 3 seconds.
- No TFP manual valve position switch DTC P1810.
- The engine is running.
- The time since the gear selector was moved is greater than 6 seconds.
- TOSS signal is greater than 500 rpm.
- TOSS signal does not increase by more than 500 rpm within a 100 ms time period for greater than 5 seconds.

DIAGNOSTIC AIDS
- The PCM will command maximum line pressure
- The condition may be intermittent. Inspect for a loose TOSS, or faulty sensor connection.
- When diagnosing for an intermittent short or open condition, massage the wiring harness while watching Scan tool for a change.
- Inspect for a damaged TOSS. Inspect for damaged transmission rotor teeth.
- PCM will calculate vehicle speed based on engine speed, TISS, and commanded gear but speedometer will remain inoperative.