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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 SSR 🢒 Restraints 🢒 SIR 🢒 DTC P0894

Object Number: 42275 Size: MF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

Circuit Description

The transmission control module (TCM) monitors the difference between engine speed and transmission output speed. In D3 drive range with the torque converter clutch (TCC) engaged, the engine speed should closely match the transmission output speed. In D4 drive range, with the 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 TP sensor DTCs P0122 or P0123.
    • No OSS 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, P0976, or P0977.
    • No 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 greater than 50 N·m (37 lb ft).
    • 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 ratio is third or fourth.
    • The transmission fluid temperature 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 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.

  1. This step tests the torque converter for slippage while in a commanded lock-up state.

DTC P0894

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Inspect for correct transmission fluid level.

Refer to Transmission Fluid Check .

Did you perform the fluid checking procedure?

--

Go to Step 3

Go to Transmission Fluid Check

3

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.

    3. Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the transmission control module (TCM).

  3. Record the DTC Freeze Frame and Failure Records.
  4. Clear the DTC.

    5. Important: It may be necessary to allow multiple torque converter clutch (TCC) cycles to occur in order to verify a slipping condition. It may also be necessary to ensure the transmission is warm before performing this step.

  5. Drive the vehicle in 4th gear with the TCC commanded ON.

Does the scan tool TCC Slip Speed measure within the specified range for 7 seconds?

130-800 RPM

Go to Step 4

Go to Diagnostic Aids

4
  1. Inspect the TCC solenoid valve for the following conditions:
    2. • Internal malfunction, such as sediment or damage
    • Damaged seals
  2. Inspect the torque converter clutch pulse width modulation (TCC PWM) solenoid valve for the following conditions:
    3. • Internal malfunction, such as sediment or damage
    • Damaged seals

Did you find and correct the condition?

--

Go to Step 14

Go to Step 5

5
  1. Inspect the 1-2 shift solenoid (SS) valve for the following conditions:
    2. • Internal malfunction, such as sediment or damage
    • Damaged seals
    • Refer to Shift Solenoid Leak Test .
  2. Inspect the 2-3 shift solenoid (SS) valve for the following conditions:
    3. • Internal malfunction, such as sediment or damage
    • Damaged seals
    • Refer to Shift Solenoid Leak Test .
  3. Inspect the 3-2 shift solenoid valve assembly for the following conditions:
    4. • Internal malfunction, such as sediment or damage
    • Damaged seals
    • Refer to Shift Solenoid Leak Test .

Did you find and correct the condition?

--

Go to Step 14

Go to Step 6

6

Inspect the valve body assembly for the following conditions:

    • Stuck regulator apply valve
    • Scored regulator apply valve body
        Refer to Control Valve Body Disassemble in the 4L60-E section of the Transmission Unit Repair Manual.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 7

7

Inspect the torque converter assembly for the following conditions:

    • Front stator shaft bushing for wear
    • Stator roller clutch not holding
    • External damage/leaks
        Refer to Torque Converter End Play Inspection in the 4L60-E section of the Transmission Unit Repair Manual.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 8

8

Inspect the oil pump assembly for the following conditions:

    • A stuck converter clutch valve
    • The converter clutch valve is assembled backwards
    • A mispositioned converter clutch valve retaining ring
    • A cocked converter clutch outer valve spring
    • A mispositioned pump to case gasket
    • Restricted orifice cup plugs
    • Damaged orifice cup plugs
    • Over-tightened, or unevenly tightened pump body to cover bolts

Refer to Oil Pump Cover Disassemble in the 4L60-E section of the Transmission Unit Repair Manual.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 9

9

Inspect the input housing and shaft assembly for the following conditions:

    • Cut turbine shaft O-ring seal
    • Damaged turbine shaft O-ring seal
    • Restricted turbine shaft retainer and ball assembly
    • Damaged turbine shaft retainer and ball assembly

Refer to Input Housing and Shaft Assembly Inspection in the 4L60-E section of the Transmission Unit Repair Manual.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 10

10
    • Inspect the 2-4 band assembly for the following conditions:
       - Worn 2-4 band
       - Damaged 2-4 band
       - Mispositioned 2-4 band
       - Misassembled 2-4 band
       - The band anchor pin is not engaged
       - Refer to 2-4 Band Installation in the 4L60-E section of the Transmission Unit Repair Manual.
    • Inspect the 2-4 servo assembly for the following conditions:
       - Restricted apply passages in the 2-4 servo assembly
       - Blocked apply passages in the 2-4 servo assembly
       - Nicks or burrs on the 2nd apply piston pin
       - Damaged 2nd apply piston pin
       - Incorrect 2nd apply piston pin
       - Nicks or burrs on the pin bore in the case
       - Damaged fourth servo piston
       - Misassembled fourth servo piston
       - Damaged servo bore in the case
       - Missing piston seals
       - Cut piston seals
       - Damaged piston seals
       - Porosity in the pistons
       - Porosity in the cover
       - Porosity in the case
       - Damaged piston seal grooves
       - Plugged orifice cup plug
       - Missing orifice cup plug

Refer to 2-4 Servo Disassemble , 2-4 Band Servo Piston Pin Length Check and 2-4 Servo Assembly Installation in the 4L60-E section of the Transmission Unit Repair Manual.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

11

Inspect the forward clutch assembly for the following conditions:

    • Worn clutch plates
    • Porosity in the forward clutch piston
    • Damaged forward clutch piston
    • Missing forward clutch piston inner and outer seals
    • Cut forward clutch piston inner and outer seals
    • Damaged forward clutch piston inner and outer seals
    • Missing input housing to forward clutch housing O-ring seal
    • Cut input housing to forward clutch housing O-ring seal
    • Damaged input housing to forward clutch housing O-ring seal
    • Damaged forward clutch housing
    • Damaged forward clutch housing retainer and ball assembly
    • Forward clutch housing retainer and ball assembly is not sealing

Refer to Forward Clutch Assembly Assemble in the 4L60-E section of the Transmission Unit Repair Manual.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

12

Inspect the 3-4 clutch assembly for the following conditions:

    • Worn clutch plates
    • Porosity in the 3-4 clutch piston
    • Damaged 3-4 clutch piston
    • Missing 3-4 clutch inner and outer seals
    • Cut 3-4 clutch inner and outer seals
    • Damaged 3-4 clutch inner and outer seals
    • Damaged 3-4 clutch spring assembly
    • Damaged 3-4 clutch apply ring
    • Damaged piston seal grooves
    • Plugged orifice cup plug
    • Missing orifice cup plug

Refer to 3-4 Clutch Assemble and 3-4 Clutch Plate Travel Check in the 4L60-E section of the Transmission Unit Repair Manual.

Did you find and correct the condition?

--

Go to Step 13

Go to Testing for Intermittent Conditions and Poor Connections

13
  1. Change the AT fluid and filter.
  2. Inspect for correct transmission fluid level.

    3. Refer to Transmission Fluid Check .

  3. Add new AT fluid as necessary.

    4. Important: The Clear TAP function will clear all adapt cells. This may affect transmission performance. The TCM will update the transmission adapt cell values as the vehicle is driven.

  4. With a scan tool, perform the Clear TAP function.

Did you complete the above procedure?

--

Go to Step 14

--

14

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
    4. • Drive the vehicle in D4, with the TCC ON, and a throttle position at 10%.
    • Ensure that the scan tool TCC Slip Speed is -25 to +25 RPM for at least 10 seconds.
  4. Select Specific DTC.
  5. Enter DTC P0894.

Has the test run and passed?

--

Go to Step 15

Go to Step 2

15

With the scan tool, observe the stored information, capture info, and DTC Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK