DTC P1870 Transmission Component Slipping 4.3L
Circuit Description
The vehicle control module (VCM) 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 VCM detects excessive TCC slip when the TCC should be engaged,
then DTC P1870 sets. DTC P1870 is a type B DTC.
Conditions for Running the DTC
| • | No TP sensor DTCs P0122 or P0123. |
| • | No VSS assembly DTCs P0502 or P0503. |
| • | No TFT sensor DTCs P0711, P0712 or P0713. |
| • | No TCC solenoid valve DTC P0740. |
| • | No 1-2 SS valve DTC P0753. |
| • | No 2-3 SS valve DTC P0758. |
| • | No TFP manual valve position switch DTC P1810. |
| • | No TCC PWM solenoid valve DTC P1860. |
| • | The engine speed is greater than 450 RPM for 5 seconds. |
| • | The engine is not in fuel cutoff. |
| • | The vehicle speed is 48-112 km/h (30-70 mph). |
| • | The engine speed is 1500-3000 RPM. |
| • | The speed ratio is 0.69-0.88 (speed ratio is engine speed
divided by the output speed). |
| • | The engine torque is 50-400 lb ft. |
| • | The engine vacuum is 0-150 kPa. |
| • | The commanded gear is not 1st gear. |
| • | The TFT is 20-130°C (68-266°F). |
| • | The shift solenoid performance diagnostic counters are zero. |
Conditions for Setting the DTC
DTC P1870 sets if the following conditions occur for three TCC
cycles.
| • | The TCC is commanded ON for 5 seconds. |
| • | The TCC is at maximum duty cycle (95%) for 5 seconds. |
| • | The TCC slip speed is 130-800 RPM for 7 seconds. |
Action Taken When the DTC Sets
| • | The VCM illuminates the malfunction indicator lamp (MIL) during
the second consecutive trip in which the conditions for setting the DTC are
met. |
| • | The VCM inhibits TCC engagement. |
| • | The VCM commands maximum line pressure. |
| • | The VCM inhibits 4th gear if the transmission is in hot mode. |
| • | The VCM freezes shift adapts from being updated. |
| • | The VCM stores DTC P1870 in VCM history during the second
consecutive trip in which the conditions for setting the DTC are met. |
Conditions for Clearing the MIL/DTC
| • | The VCM turns OFF the MIL during the third consecutive trip in
which the diagnostic test runs and passes. |
| • | A scan tool clears the DTC from VCM history. |
| • | The VCM clears the DTC from VCM history if the vehicle completes
40 warm-up cycles without an emission-related diagnostic fault occurring. |
| • | The VCM cancels the DTC default actions when the fault no longer
exists and the ignition switch is OFF long enough in order to power down the
VCM. |
Diagnostic Aids
Internal transmission failures could set a DTC P1870.
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 P1870 Transmission Component Slipping (4.3L)
Step
| Action
| Value(s)
| Yes
| No
|
1
| Was the Powertrain On-Board Diagnostic
(OBD) System Check performed?
| --
|
Go to Step
2
| Go to
Powertrain On Board Diagnostic (OBD) System Check
in Engine Controls
|
2
| Perform the transmission fluid checking procedure.
Refer to
Transmission Fluid Check
.
Did you perform the fluid checking procedure?
| --
|
Go to Step 3
| Go to
Transmission Fluid Check
|
3
|
- Install the Scan Tool
.
- With the engine OFF, turn the ignition switch to the RUN position.
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 VCM.
- Record the DTC Freeze Frame and Failure Records.
- Clear the DTC.
- Drive the vehicle in 4th gear with the TCC commanded ON.
Is the scan tool TCC Slip Speed within the specified range for 7 seconds?
| 130-800 RPM
|
Go to Step 4
| Go to Diagnostic Aids
|
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 a condition?
| --
|
Go to Step
13
|
Go to Step 5
|
5
|
- Inspect the 1-2 shift solenoid (SS) valve for the following conditions:
| • | Internal malfunction (such as sediment or damage) |
| • | Refer to Shift Solenoid Leak Test
. |
- Inspect the 2-3 shift solenoid (SS) valve for the following conditions:
| • | Internal malfunction (such as sediment or damage) |
| • | Refer to Shift Solenoid Leak Test
. |
Did you find a condition?
| --
|
Go to Step
13
|
Go to Step 6
|
6
| Inspect the valve body assembly for a stuck regulator apply valve.
Refer to Unit Repair.
Did you find a condition?
| --
|
Go to Step
13
|
Go to Step 7
|
7
| Inspect the torque converter assembly for the following conditions:
| • | Stator roller clutch not holding |
Did you find a 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 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 Unit Repair.
Did you find a 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 Unit Repair.
Did you find a 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. |
| • | Restricted apply passages in the 2-4 servo assembly |
| • | Blocked apply passages in the 2-4 servo assembly |
| • | Nicks or burrs on the servo pin |
| • | Nicks or burrs on the pin bore in the case |
| • | Damaged fourth servo piston |
| • | Misassembled fourth servo piston |
| • | Incorrect band apply pin |
| • | Damaged servo bore in the case |
| • | Porosity in the pistons |
| • | Damaged piston seal grooves |
| • | Plugged orifice cup plug |
| • | Missing orifice cup plug |
Refer to Unit Repair.
Did you find a 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 Unit Repair.
Did you find a 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 Unit Repair.
Did you find a condition?
| --
|
Go to Step
13
| Go to Diagnostic Aids
|
13
| 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 9-35%. |
| • | Ensure that the scan tool TCC Slip Speed is -20 to +50 RPM
for at least 7 seconds. |
- Select Specific DTC.
- Enter DTC P1870.
Has the test run and passed?
| --
| System OK
|
Go to Step
1
|
DTC P1870 Transmission Component Slipping 4.8L and 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 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 P1870 sets. DTC P1870 is a type B DTC.
Conditions for Running the DTC
| • | No MAF sensor DTCs P0101, P0102 or P0103. |
| • | No TP sensor DTCs P0122 or P0123. |
| • | No VSS assembly DTCs P0502 or P0503. |
| • | No TFT sensor DTCs P0711, P0712 or P0713. |
| • | No TCC solenoid valve DTC P0740. |
| • | No 1-2 SS valve DTC P0753. |
| • | No 2-3 SS valve DTC P0758. |
| • | No TFP manual valve position switch DTC P1810. |
| • | No TCC PWM solenoid valve DTC P1860. |
| • | The engine speed is greater than 300 RPM for 5 seconds. |
| • | The engine is not in fuel cutoff. |
| • | The vehicle speed is 48-112 km/h (30-70 mph). |
| • | The engine speed is 1500-3000 RPM. |
| • | The speed ratio is 0.69-0.88 (speed ratio is engine speed
divided by the transmission output speed). |
| • | The engine torque is 50-400 lb ft. |
| • | The engine vacuum is 0-105 kPa. |
| • | The commanded gear is not 1st gear. |
| • | The TFT is 20-130°C (68-266°F). |
| • | The shift solenoid performance diagnostic counters are zero. |
Conditions for Setting the DTC
DTC P1870 sets if the following conditions occur for three TCC
cycles.
| • | The TCC is commanded ON for 5 seconds. |
| • | The TCC is at maximum duty cycle (90%) for 3 seconds. |
| • | The TCC slip speed is 130-800 RPM for 7 seconds. |
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 inhibits TCC engagement. |
| • | The PCM commands maximum line pressure. |
| • | The PCM inhibits 4th gear if the transmission is in hot mode. |
| • | The PCM freezes shift adapts from being updated. |
| • | The PCM stores DTC P1870 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 clears the DTC from PCM history. |
| • | 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 the ignition switch is OFF long enough in order to power down the
PCM. |
Diagnostic Aids
Internal transmission failures could set a DTC P1870.
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 P1870 Transmission Component Slipping (4.8L and 5.3L)
Step
| Action
| Value(s)
| Yes
| No
|
1
| Was the Powertrain On-Board Diagnostic
(OBD) System Check performed?
| --
|
Go to Step
2
| Go to
Powertrain On Board Diagnostic (OBD) System Check
in Engine Controls
|
2
| Perform the transmission fluid checking procedure.
Refer to
Transmission Fluid Check
.
Did you perform the fluid checking procedure?
| --
|
Go to Step 3
| Go to
Transmission Fluid Check
|
3
|
- Install the Scan Tool
.
- With the engine OFF, turn the ignition switch to the RUN position.
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.
- Drive the vehicle in 4th gear with the TCC commanded ON.
Is the scan tool TCC Slip Speed within the specified range for 7 seconds?
| 130-800 RPM
|
Go to Step 4
| Go to Diagnostic Aids
|
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 a condition?
| --
|
Go to Step
13
|
Go to Step 5
|
5
|
- Inspect the 1-2 shift solenoid (SS) valve for the following conditions:
| • | Internal malfunction (such as sediment or damage) |
| • | Refer to Shift Solenoid Leak Test
. |
- Inspect the 2-3 shift solenoid (SS) valve for the following conditions:
| • | Internal malfunction (such as sediment or damage) |
| • | Refer to Shift Solenoid Leak Test
. |
Did you find a condition?
| --
|
Go to Step
13
|
Go to Step 6
|
6
| Inspect the valve body assembly for a stuck regulator apply valve.
Refer to Unit Repair.
Did you find a condition?
| --
|
Go to Step
13
|
Go to Step 7
|
7
| Inspect the torque converter assembly for the following conditions:
| • | Stator roller clutch not holding |
Did you find a 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 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 Unit Repair.
Did you find a 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 Unit Repair.
Did you find a 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. |
| • | Restricted apply passages in the 2-4 servo assembly |
| • | Blocked apply passages in the 2-4 servo assembly |
| • | Nicks or burrs on the servo pin |
| • | Nicks or burrs on the pin bore in the case |
| • | Damaged fourth servo piston |
| • | Misassembled fourth servo piston |
| • | Incorrect band apply pin |
| • | Damaged servo bore in the case |
| • | Porosity in the pistons |
| • | Damaged piston seal grooves |
| • | Plugged orifice cup plug |
| • | Missing orifice cup plug |
Refer to Unit Repair.
Did you find a 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 Unit Repair.
Did you find a 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 Unit Repair.
Did you find a condition?
| --
|
Go to Step
13
| Go to Diagnostic Aids
|
13
| 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 9-35%. |
| • | Ensure that the scan tool TCC Slip Speed is -20 to +50 RPM
for at least 7 seconds. |
- Select Specific DTC.
- Enter DTC P1870.
Has the test run and passed?
| --
| System OK
|
Go to Step
1
|
