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 transaxle will be set to hot mode operation.

1. With transaxle temperature sensor or wiring open, PCM data PD77 will read -35°C or less. If parameter does not show this, sensor and circuit is okay.
2. Check for open in circuit No. 585 between PCM and sensor connector. If PCM data PD77 reads 148-151°C with sensor terminal "M" jumpered to ground, the circuit No. 585 and PCM are okay.
3. Checks circuit No. 452 for open to PCM terminal connector.
4. Checks PCM's ability to recognize low voltage on PCM terminal 1B14 (transaxle temperature sensor input). If grounding PCM terminal 1B14 caused PCM data PD77 to read 148-151°C, check for open in circuit No. 585 between PCM and sensor connector.
5. Checks for 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.