DTC P059: Open Transaxle Temperature Sensor Circuit: Action

1. PCM turns on the "SERVICE VEHICLE SOON" message.
2. PCM will substitute coolant temperature value for transaxle temperature until coolant temperature reaches 115°C then the transaxle will be set to hot mode operation.

NOTE: Numbers in list refer to circled numbers in diagnostic flow chart, see Fig 1. For circuit identification see Fig 2.

1. With the transaxle temperature sensor or wiring open circuited PCM data PD77 will read -35°C or less. If the parameter does not show this, then the sensor and wiring are OK.
2. Checking for an open in CKT 585 between the PCM and connector "C111". If PD77 shows 148-151°C with the "C111" terminal "D" jumpered to ground, then CKT 585 and PCM are OK.
3. Checking CKT 469 for an open to PCM terminal "2D1".
4. Checking the PCM's ability to recognize low voltage on terminal "1B14", transaxle temperature sensor input. If grounding terminal "1B14" causes PD77 to show 148-151°C, then there is an open in CKT 585 between the PCM and connector "C111".

Fig 1: DTC P059: Open Transaxle Temperature Sensor Circuit Flow Chart

Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC P059: Open Transaxle Temperature Sensor Circuit Flow Chart Circuit

Courtesy of GENERAL MOTORS CORP.