Code 15

This DTC does NOT flash the CHECK TRANS indicator and does NOT set the BACKUP MODE.

CIRCUIT DESCRIPTION:
The transmission oil temperature sensor is a thermistor within the internal wiring harness of the transmission in the adaptor case oil pan. The Transmission Control Module (TCM) applies 5 volts to the sensor connector M-6 terminal 3(C). The other side of the sensor is connected to ground through the TCM terminal C14.
When the transmission oil is cold, the sensor resistance is high and the TCM will sense high signal voltage.
As the transmission oil temperature warms to normal transmission operating temperature of 80°C (176°F), the sensor resistance becomes less and the voltage decreases at about 3.5 volts. Note, for more accuracy the measurement is done differently for low temperature (less than 45°C) and high temperature (more than 50°C).
- When DTC15 is set, the transmission will use a warm value for operation, but the scan tool will display the actual oil temperature.
- Table shows thermistor resistance at different temperatures.

DIAGNOSTIC AIDS:
- This Diagnostic is an electrical test done by the TCM.
- Detection Conditions:
- Voltage between terminals B3 and C14 > 4.74 volts.
- The condition needs to be present for at least 20 seconds. Note: during the detection time the TCM reads the high voltage that defines a -40°C temperature.
- Action after the detection time: Default Transmission Oil Temperature is set to 100°C. But winter mode still available.
- Recovery conditions: To recover when voltage < or = to 4.74 volts after detection time.