Allison Automatic Transmission

ALLISON AUTOMATIC TRANSMISSION

DTC P0711

DTC P0711 Step 1 - 5:

DTC P0711 Step 6 - 12:

Circuit Description for Allison Automatic Transmission
The Transmission Fluid Temperature (TFT) sensor is a part of the transmission Pressure Switch Manifold (PSM) assembly. The TFT sensor is a thermistor, which changes value based on temperature of the transmission fluid. The sensor has a negative-temperature coefficient. This means that as the temperature increases, the resistance decreases, and as the temperature decreases the resistance increases. The Transmission Control Module (TCM) supplies a 5 V reference signal to the TFT sensor and measures the voltage drop in the circuit. As the fluid temperature warms to a normal operating temperature, the resistance becomes less and the signal voltage decreases. The TCM uses this information to control shift quality and torque converter clutch apply. DTC P0711 is a type B DTC.

Conditions for Running the DTC
^ No DTC, P0721, P0722, P0717, P0716, P0713, P0712
^ The components are powered and ignition voltage is greater than 9 V and less than 18 V.
^ Engine speed is greater than 200 RPM and less than 7,500 RPM for 5 seconds.
^ Engine has been running for 2 seconds.
^ Engine speed is above 450 RPM and output speed is above 100 RPM.
^ The transmission fluid temperature is in the range -35°C (-31°F) to 149°C (300°F).

Conditions for Setting the DTC
DTC P0711 sets when the TCM detects one of the following conditions:
^ The TCM detects a temperature change that is under a set limit when compared to samples of the minimum and maximum temperature values.
^ The TFT has an unrealistic temperature change of more than 10°C (50°F) for 10 occurrences.
^ The temperature from start-up decreases 40°C (104°F) or more within duration of 6 or more seconds.

Action Taken When the DTC Sets
^ The TCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
^ The TCM freezes shift adapts.
^ The TCM records the operating conditions when the conditions for setting the DTC are met. The TCM stores this information as Failure Records.
^ The TCM stores DTC P0218 in TCM history.
^ TCM inhibits TCC engagement.

Conditions for Clearing the MIL/DTC
A Scan Tool can clear the code from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

Diagnostic Aids
^ The Transmission Fluid Temperature (TFT) should rise steadily during warm-up cycles then stabilize.
^ DTC P0218 may set after DTC P0711 has set. Follow the diagnostic table for DTC P0711 before proceeding to the diagnostic for the DTC P0218.
^ Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
- A bent terminal
- A backed-out terminal
- A damaged terminal
- Poor terminal tension
- A chafed wire
- A broken wire inside the insulation.
^ When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
^ You may have to drive the vehicle in order to experience a fault.
^ An open condition at circuit (CKT 2762) may allow a ground path internally through circuit (CKT 2471). If this occurs, the TCM sees a temperature that appears to be within normal operation, about -22°C (-7.6°F) and initially a code will not be set. However, the transmission will still inhibit shift adapts and TCC operation. It may take several minutes before a P0711 code is set to indicate a failure.

Test Description
The numbers refer to the step numbers on the diagnostic table.
4. This step tests 5 V reference signal from TCM.
5. This step tests the integrity of the AT wiring harness assembly.
6. This step tests for a short or open in the Engine Wiring Harness.