Code P057, Shorted Transaxle Temperature Sensor Circuit: Action

WARNING: This page is about a different car, the 1995 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.

PCM turns on SERVICE VEHICLE SOON message. PCM substitutes engine coolant temperature value for transaxle temperature until engine coolant temperature reaches 221°F (105°C) before it sets to hot mode operation. Transaxle shift adapts and garage shift adapts are maintained in current levels.

NOTE: Test numbers refer to numbers on diagnostic chart.

If transaxle temperature sensor is shorted, PCM data parameter PD77 should read 298°F (148°C) or greater. If parameter does not show this reading, sensor and wiring are okay.
Checks if circuit No. 585 (Tan/White wire) is shorted. If parameter value stays at -18°F (-28°C) or greater with transaxle temperature sensor connector disconnected, check for short between sensor connector and PCM terminal No. 1B14.
Checks for short to ground on circuit No. 585 (Tan/White wire) inside transaxle. If wire is okay, replace shorted transaxle temperature sensor.

Fig 1: Code P057 Schematic, Shorted Transaxle Temp. Sensor Circuit

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P057 Diagnostic Flow Chart, Shorted Transaxle Temp. Sensor Ckt.

Courtesy of GENERAL MOTORS CORP.