DTC P0894 4.2L
Circuit Description
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 torque converter clutch (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.
Conditions for Running the DTC
| • | No throttle position (TP) sensor DTCs P1120 or P1220. |
| • | No vehicle speed sensor (VSS) assembly DTCs P0502 or P0503. |
| • | No TCC solenoid valve DTC P0740. |
| • | No 1-2 SS valve DTC P0753. |
| • | No 2-3 SS valve DTC P0758. |
| • | No 3-2 SS valve assembly DTC P0785. |
| • | No transmission fluid pressure (TFP) manual valve position switch
DTC P1810. |
| • | No TCC/pulse width modulated (PWM) solenoid valve DTC P1860. |
| • | The engine speed is greater than 450 RPM for 5 seconds. |
| • | The engine is not in fuel cutoff. |
| • | The engine torque is 68-542 N·m (50-400 lb ft). |
| • | The engine vacuum is 0-105 kPa (0-15 psi). |
| • | The TP angle is 20-99 percent. |
| • | The vehicle speed is 48-131 km/h (30-82 mph). |
| • | The engine speed is 1,500-3,000 RPM. |
| • | The speed ratio is 0.69-0.88, speed ratio is engine speed
divided by the transmission output speed. |
| • | The commanded gear is not 1st gear. |
| • | The TFT is 20-150°C (68-302°F). |
| • | The shift solenoid performance diagnostic counters are zero. |
Conditions for Setting the DTC
DTC P0894 sets if the following conditions occur for three TCC
cycles.
| • | The TCC is commanded ON for 5 seconds. |
| • | The TCC is at 40 percent duty cycle for 5 seconds. |
| • | The TCC slip speed is 130-800 RPM for 7 seconds. |
| | Important: The following actions may occur before the DTC sets.
|
| • | If the TCC is commanded ON for 5 seconds, the TCC is at 40 percent
duty cycle for 5 seconds, the TP angle is 20-99 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 130-800 RPM for 7 seconds,
then the PCM 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 130-800 RPM
for 7 seconds, then the PCM will command the TCC OFF for 1.5 seconds.
Condition 3
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.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during
the second consecutive trip in which the Conditions for Setting the DTC are
met. |
| • | The PCM commands maximum line pressure. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM inhibits 4th gear if the transmission is in hot mode. |
| • | The PCM freezes shift adapts from being updated. |
| • | The PCM records the operating conditions when the Conditions for
Setting the DTC are met. The PCM stores this information as Freeze Frame and
Failure Records. |
| • | The PCM stores DTC P0894 in PCM history during the second
consecutive trip in which the Conditions for Setting the DTC are met. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL during the third consecutive trip in
which the diagnostic test runs and passes. |
| • | A scan tool can clear the MIL/DTC. |
| • | The PCM clears the DTC from PCM history if the vehicle completes
40 warm-up cycles without an emission-related diagnostic fault
occurring. |
| • | The PCM cancels the DTC default actions when the fault no longer
exists and/or the ignition switch is OFF long enough in order to power down
the PCM. |
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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the torque converter for
slippage while in a commanded lock-up state.
DTC P0894 (4.2L)
Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the Diagnostic System Check - Engine Controls?
| --
| Go to
Step 2
| Go to
Diagnostic System Check - Engine Controls
in Engine Controls-4.2L
|
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
|
- Install 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 - 4.2L
|
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 - 4.2L
|
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: Performing the Service Procedure to Clear TAPS will clear all adapt
cells. This may affect Transmission performance. The PCM will update the transmission
adapt cell values as the vehicle is driven.
- Use the Service Procedure that disconnects power to the PCM for approximately
30 minutes to clear TAPS.
Refer to
Powertrain Control Module Replacement
in Engine Controls -
4.2L.
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 - 4.2L
| System OK
|
DTC P0894 5.3L
Circuit Description
The powertrain control module (PCM) 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 PCM detects excessive TCC slip when the TCC should be engaged,
then DTC P0894 sets. DTC P0894 is a type B DTC.
Conditions for Running the DTC
| • | No throttle position (TP) sensor DTCs P0122 or P0123. |
| • | No vehicle speed sensor (VSS) assembly DTCs P0502 or P0503. |
| • | No TCC solenoid valve DTC P0740. |
| • | No 1-2 SS valve DTC P0753. |
| • | No 2-3 SS valve DTC P0758. |
| • | No 3-2 SS valve assembly DTC P0785. |
| • | No transmission fluid pressure (TFP) manual valve position switch
DTC P1810. |
| • | No TCC/pulse width modulated (PWM) solenoid valve DTC P2761. |
| • | The engine speed is greater than 450 RPM for 5 seconds. |
| • | The engine is not in fuel cutoff. |
| • | The engine torque is 68-542 N·m (50-400 lb ft). |
| • | The engine vacuum is 0-105 kPa (0-15 psi). |
| • | The TP angle is 20-99 percent. |
| • | The vehicle speed is 48-131 km/h (30-82 mph). |
| • | The engine speed is 1,500-3,000 RPM. |
| • | The speed ratio is 0.69-0.88, speed ratio is engine speed
divided by the transmission output speed. |
| • | The commanded gear is not 1st gear. |
| • | The TFT is 20-150°C (68-302°F). |
| • | The shift solenoid performance diagnostic counters are zero. |
Conditions for Setting the DTC
DTC P0894 sets if the following conditions occur for three TCC
cycles.
| • | The TCC is commanded ON for 5 seconds. |
| • | The TCC is at 40 percent duty cycle for 5 seconds. |
| • | The TCC slip speed is 130-800 RPM for 7 seconds. |
| | Important: The following actions may occur before the DTC sets.
|
| • | If the TCC is commanded ON for 5 seconds, the TCC is at 40 percent
duty cycle for 5 seconds, the TP angle is 20-99 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 130-800 RPM for 7 seconds,
then the PCM 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 130-800 RPM
for 7 seconds, then the PCM will command the TCC Off for 1.5 seconds.
Condition 3
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.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during
the second consecutive trip in which the Conditions for Setting the DTC are
met. |
| • | The PCM commands maximum line pressure. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM inhibits 4th gear if the transmission is in hot mode. |
| • | The PCM freezes shift adapts from being updated. |
| • | The PCM records the operating conditions when the Conditions for
Setting the DTC are met. The PCM stores this information as Freeze Frame and
Failure Records. |
| • | The PCM stores DTC P0894 in PCM history during the second
consecutive trip in which the Conditions for Setting the DTC are met. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL during the third consecutive trip in
which the diagnostic test runs and passes. |
| • | A scan tool can clear the MIL/DTC. |
| • | The PCM clears the DTC from PCM history if the vehicle completes
40 warm-up cycles without an emission-related diagnostic fault
occurring. |
| • | The PCM cancels the DTC default actions when the fault no longer
exists and/or the ignition switch is OFF long enough in order to power down
the PCM. |
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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the torque converter for
slippage while in a commanded lock-up state.
DTC P0894 (5.3L)
Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the Diagnostic System Check - Engine Controls?
| --
| Go to
Step 2
| Go to
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
|
- Install 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 - 4.8L, 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 - 4.8L, 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 percent. |
| • | 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 - 4.8L, 5.3L and 6.0L
| System OK
|
