DTC 59

Trouble Code 59 Chart:

Transmission Fluid Switch Schematic:

CIRCUIT DESCRIPTION
The Transmission Fluid Temperature (TFT) sensor is a 2 wire thermistor located in the transaxle. This sensor operates in the same way as an Engine Coolant Temperature (ECT) or Intake Air Temperature (IAT) sensor. The Powertrain Control Module (PCM) applies 5 volts to the sensor on circuit 1227. The voltage sensed at PCM pin "A32" will be high when the trans fluid is cold, and as the trans fluid warms the voltage signal will drop. A very high signal voltage therefore indicates a low fluid temperature or failure in the sensor circuit. Normal operating temperatures range between 75° C (167° F) and 10O° C (212° F).

DIAGNOSTIC TROUBLE CODE (DTC) 59 WILL SET WHEN
Transaxle fluid temperature is indicated below - 40° C (- 40° F) for 5 seconds.

ACTION TAKEN (PCM) WILL DEFAULT TO
The Malfunction Indicator Lamp (MIL) will not become illuminated, and the PCM will use a default TFT of 90° C (194° F).

DTC 59 WILL CLEAR WHEN
A current DTC 59 will clear when the TFT is indicated above the calibrated low temperature threshold. A History DTC 59 will clear after 50 consecutive ignition key cycles without a current DTC 59 being stored.

TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.

1. This test is to determine if a current condition exists.
2. This test simulates a DTC 58. If the PCM recognizes the low signal voltage (high temperature), and the scan displays 148°C (298°F) or greater, the PCM and wiring are OK.
3. This test checks if circuit 1227 is open.

DIAGNOSTIC AIDS
Scan tool displays transmission temperature in degrees Centigrade. The temperature should rise steadily to about 90° C (212° F) then stabilize.
A faulty connection or an open in circuit 452 or circuit 1227 can result in a DTC 59.
A "skewed" sensor can result in firm shifts, or Torque Converter Clutch (TCC) enabled complaints.