Code P059, Open Transaxle Temperature Sensor Circuit: Action

PCM turns on MIL. PCM substitutes coolant temperature value for transaxle temperature until coolant temperature reaches 221°F (105°C) then sets transaxle to hot mode operation.

1. With transaxle temperature sensor or wiring open, PCM data PD19 will read -31°F (-35°C) or less. If parameter does not show this, sensor and wiring are okay.
2. Check for open in circuit No. 585 between PCM and transaxle connector. If PCM data PD77 reads 298-303°F (148-151°C) with connector terminal "F" jumpered to ground, circuit No. 585 and PCM are okay.
3. Checks circuit No. 808 for open to PCM terminal 3E11.
4. Checks PCM's ability to recognize low voltage on PCM terminal 3F12 (transaxle temperature sensor input). If grounding PCM terminal 3F12 caused PCM data PD19 to read 298-303°F (148-151°C), check for open in circuit No. 585 between PCM and transaxle connector.
5. Checks for an open transaxle temperature sensor.

Fig 1: Code P059 Schematic, Open Transaxle Temperature Sensor Circuit

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P059 Diagnostic Flow Chart, Open Transaxle Temperature Sensor Circuit

Courtesy of GENERAL MOTORS CORP.