P0894
DTC P0894
Circuit Description
The transmission control module (TCM) monitors the difference between engine speed and transmission output speed. In D3 drive range with the TCC engaged, the engine speed should closely match the transmission output speed. In D4 drive range, with the torque converter clutch (TCC) engaged, the TCC slip speed should be -20 to +50 RPM.
When the TCM detects excessive TCC slip when the TCC should be engaged, then DTC P0894 sets. DTC P0894 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0894 Transmission Component Slipping
Conditions for Running the DTC
^ No throttle position (TP) sensor DTCs P0122 or P0123.
^ No vehicle speed sensor (VSS) DTCs P0722 or P0723.
^ No TCC DTCs P0741, P0742, P2763, or P2764.
^ No 1-2 SS DTCs P0751, P0752, P0973, or P0974.
^ No 2-3 SS DTCs P0756, P0757, P0973, or P0974.
^ No transmission fluid pressure (TFP) manual valve position switch DTCs P1810, P1815, P1816.
^ The engine speed is greater than 450 RPM for 5 seconds.
^ The engine is not in fuel cutoff.
^ The engine torque is between 108 Nm (80 ft. lbs.) and 882 Nm (651 ft. lbs.).
^ The vehicle speed is 48 - 177 km/h (30 - 110 mph).
^ The engine speed is 1,200 - 3,750 RPM.
^ The speed ratio is 0.70-2.25, speed ratio is engine speed divided by the transmission output speed.
^ The gear range is D4.
^ The commanded gear is not 1st gear.
^ The transmission fluid temperature (TFT) is 20 - 130°C (68 - 266°F).
^ The shift solenoid performance diagnostic counters are zero.
Conditions for Setting the DTC
DTC P0894 sets if the following conditions occur for 3 TCC cycles.
^ The TCC is commanded ON for 5 seconds.
^ The throttle position is greater than 10 percent.
^ The TCC slip speed is 100 - 550 RPM for 10 seconds.
^ Important:
The following actions may occur before the DTC sets.
If the TCC is commanded ON for 10 seconds, the TCC is at 75 percent duty cycle for 5 seconds, the TP angle is 10-99 percent and the transmission slip counter has incremented to either 1 or 2, out of 3 to increment the fail counter for the current ignition cycle, then the following slip conditions and actions may increment the fail counter for the current ignition cycle:
^ These conditions must occur sequentially.
Condition 1
If the TCC slip speed is 100 - 550 RPM for 10 seconds, then the TCM will command maximum line pressure and freeze shift adapts from being updated.
Condition 2
If Condition 1 is met and the TCC slip speed is 100 - 550 RPM for 10 seconds, then the TCM will command the TCC OFF for 1.5 seconds.
Condition 3
^ If Condition 2 is met and the TCC slip speed is 100 - 550 RPM for 10 seconds, then the fail counter on the current ignition cycle is incremented.
^ The above slip conditions and actions may be disregarded if the TCC is commanded OFF at any time as a result of a driving maneuver, sudden acceleration or deceleration.
Action Taken When the DTC Sets
^ The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
^ The TCM commands maximum line pressure.
^ The TCM freezes transmission adaptive functions.
^ The TCM inhibits TCC.
^ The TCM inhibits 4th gear if in hot mode.
^ At the time of the first failure, the TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record.
^ At the time of the second failure, the ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame.
^ The TCM stores DTC P0752 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.
Conditions for Clearing the DTC
^ The ECM turns OFF the MIL after the 4th consecutive drive trip in which the TCM does not send a MIL illumination request.
^ A scan tool can clear the DTC.
^ The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
^ The TCM cancels the DTC default actions when the ignition is OFF long enough in order to power down the TCM.
Diagnostic Aids
^ Bronze material found in the transmission oil pan may indicate stator shaft bushing wear. If bushing wear is suspected, inspect the stator shaft and the input, turbine, shaft for damage.
^ Refer to Symptoms - Automatic Transmission for more information.
Test Description
The number below refers to the step number on the diagnostic table.
3. This step tests the torque converter for slippage while in a commanded lock-up state.
Step 1 - Step 6:
Step 7 - Step 10:
