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 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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0894 Transmission Component Slipping
Conditions for Running the DTC
• | No TP sensor DTCs P1120 or P1220. |
• | No VSS 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 TFP manual valve position switch DTC P1810. |
• | No TCC 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 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 3 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 TCM freezes transmission adaptive functions. |
• | 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
| Values
| Yes
| No
|
1
| Did you perform the Diagnostic System Check - Vehicle?
| --
| Go to
Step 2
| Go to
Diagnostic System Check - Vehicle
in Vehicle DTC Information
|
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 powertrain control module (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
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems
|
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
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems
|
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 TAP will clear all adapt cells. This may affect Transmission performance. The PCM will update the transmission adapt cell values as the vehicle is driven.
- 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:
- 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 - Vehicle
in Vehicle DTC Information
| System OK
|
DTC P0894 5.3L
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 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. |
Test Description
The number below refers to the step number on the diagnostic table.
-
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
|
- 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 transmission control module (TCM).
- Record the DTC Freeze Frame and Failure Records.
- Clear the DTC.
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.
- 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
|
- Inspect the 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
Testing for Intermittent Conditions and Poor Connections
|
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 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.
- 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:
- 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 at 10%. |
• | Ensure that the scan tool TCC Slip Speed is -25 to +25 RPM for at least 10 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 - Vehicle
| System OK
|