The powertrain control module (PCM) 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 TCC engaged, the TCC slip speed should be -20
to +50 RPM.
When the PCM detects excessive TCC slip when the TCC should be engaged,
then DTC P0894 sets. DTC P0894 is a type B DTC.
DTC P0894 sets if the following conditions occur for three TCC
cycles.
If the TCC slip speed is 130-800 RPM for 7 seconds,
then the PCM will command maximum line pressure and freeze shift adapts from
being updated.
If Condition 1 is met and the TCC slip speed is 130-800 RPM
for 7 seconds, then the PCM will command the TCC Off for 1.5 seconds.
If Condition 2 is met and the TCC slip speed is 130-800 RPM
for 7 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.
The numbers below refer to the step numbers on the diagnostic table.
DTC P0894
Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the Powertrain Diagnostic System Check?
| --
| Go to
Step 2
| Go to
Diagnostic System Check - Engine Controls
in Engine Controls - 4.3L or
Diagnostic System Check - Engine Controls
in Engine Controls - 4.8L, 5.3L and 6.0L
|
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
|
- With a scan tool.
- Turn ON the ignition, with the engine OFF.
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 PCM.
- Record the DTC Freeze Frame and Failure Records.
- Clear the DTC.
Important: It may be necessary to allow multiple 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.
- 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
Intermittent Conditions
in Engine Controls - 4.3L or
Intermittent Conditions
in Engine Controls - 4.8L, 5.3L and 6.0L
|
4
|
- Inspect the torque converter clutch (TCC) solenoid valve for the
following conditions:
• | Internal malfunction, such as sediment or damage |
- Inspect the torque converter clutch pulse width modulation (TCC PWM)
solenoid valve for the following conditions:
• | Internal malfunction, such as sediment or damage |
Did you find and correct the condition?
| --
| Go to
Step 14
| Go to
Step 5
|
5
|
- Inspect the 1-2 shift solenoid (SS) valve for the following conditions:
• | Internal malfunction, such as sediment or damage |
- Inspect the 2-3 shift solenoid (SS) valve for the following conditions:
• | Internal malfunction, such as sediment or damage |
- Inspect the 3-2 shift solenoid valve assembly for the following
conditions:
• | Internal malfunction, such as sediment or damage |
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 |
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 |
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:
• | The band anchor pin is not engaged |
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 |
• | Porosity in the pistons |
• | 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:
• | 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:
• | 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
Intermittent Conditions
in Engine Controls - 4.3L or
Intermittent Conditions
in Engine Controls - 4.8L, 5.3L and 6.0L
|
13
|
- Change the AT fluid and filter.
- Inspect for correct transmission fluid level.
Refer
to
Transmission Fluid Check
.
- Add new AT fluid as necessary.
Important: The Clear TAPS function will clear all adapt cells. This may affect
transmission performance. The PCM will update the transmission adapt cell
values as the vehicle is driven.
- Using the scan tool, perform the Clear TAPS function.
Did you complete the above procedure?
| --
| Go to
Step 14
| --
|
14
| Perform the following procedure in order to verify the repair:
- Select DTC.
- Select Clear Info.
- Operate the vehicle under the following conditions:
• | Drive the vehicle in D4, with the TCC ON, and a throttle position
of 20-99%. |
• | Ensure that the scan tool TCC Slip Speed is -20 to +50 RPM
for at least 7 seconds. |
- Select Specific DTC.
- 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
in Engine Controls - 4.3L or
Diagnostic Trouble Code (DTC) List
in Engine Controls - 4.8L, 5.3L and 6.0L
| System OK
|