Workshop Manual

TRANSMISSION CONTROL SYSTEM (4L30–E)
7A1–39
DTC P0713 Transmission Fluid Temperature (TFT) Sensor Circuit High Input
D07R200004
Circuit Description
The TFT sensor is a thermistor that controls the signal
voltage to the PCM. The PCM supplies a 5–volt reference
signal to the sensor on circuit RED/BLK. When the
transmission fluid is cold, the sensor resistance is high
and the PCM will sense high signal voltage. As the
transmission fluid temperature warms to the normal
operating temperature of 100°C (212°F), the sensor
resistance becomes less and the voltage decreases to
about 1.5 to 2 volts.
This DTC detects a continuous open or short to power in
the TFT signal circuit or the TFT sensor. This is a type “D”
DTC.
Conditions For Setting The DTC
B Battery voltage is between 10 and 16 volts.
B Ignition is “on”.
B TFT sensor indicating a voltage greater than 4.86
volts.
B All conditions met for 20 seconds.
Action Taken When The DTC Sets
B Transmission default temperature will be:
80°C (176°F) if engine temperature code is set.
100°C (212°F) if engine temperature is warm.
80°C (176°F) if engine run time is greater than 5
minutes.
21°C (69.8°F) if engine run time is less than 5
minutes.
B The PCM will not illuminate the Malfunction Indicator
Lamp (MIL).
Conditions For Clearing The DTC
B The DTC can be cleared from the PCM history by
using a scan tool.
B The DTC will be cleared from history when the vehicle
has achieved 40 warmup cycles without a failure
reported.
B The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled “off”
long enough to power down the PCM.
Diagnostic Aids
B Inspect the wiring for poor electrical connection at the
PCM and transmission 7-way connector. Look for
possible bent, backed out, deformed or damaged
terminals. Check for weak terminal tension as well.
Also check for a chafed wire that could short to bare
metal or other wiring. Inspect for a broken wire inside
the insulation.
B When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.
B Scan tool displays transmission fluid temperature in
degrees. After transmission is operating, the
temperature should rise steadily to about 100°C
(212°F), then stabilize.
B The temperature to resistance value scale may be
used to check the TFT sensor at the various
temperature levels to evaluate the possibility of a
“skewed” (mis–scaled) sensor.
A “skewed” sensor could result in hard shifts or TCC
complaints.
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
3. This check verifies problem in the TFT sensor circuit.
4. This test simulates a TFT sensor DTC P0712. If the
PCM recognizes the low signal voltage (high
temperature), and the scan tool displays 146°C
(295°F) or greater, the PCM and wiring are OK.
5. This test checks the TFT sensor and internal wiring
harness.