The 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 +20 RPM.
When the VCM detects excessive TCC slip when the TCC should be engaged,
then DTC P1870 sets. DTC P1870 is a type A DTC.
The following conditions are met for three TCC cycles with reported
excessive TCC slip conditions.
The numbers below refer to the step numbers on the diagnostic table.
DTC P1870 Transmission Slipping Component
Step
| Action
| Value(s)
| Yes
| No
|
1
| Was the Powertrain On-Board Diagnostic (OBD) System Check performed?
| --
|
Go to Step 2
| |
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 (tech 1)
®.
- Turn ON the ignition, with the engine OFF.
Important: Before clearing the DTCs, 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 Freeze Frame and Failure Records.
- Clear the DTCs.
- With the engine idling and at normal operating temperature, apply
the brake pedal.
- Select each transmission range: D1, D2, D3, D4, N, R and P.
Refer to Transmission Fluid Pressure (TFP) Manual Valve Position Switch
Logic.
Does each selected transmission range match the scan tool TFP switch A/B/C display?
| --
|
Go to Step 4
| Go to
Transmission Fluid Pressure Manual Valve Position Switch Resistance Check
|
4
|
- Install the scan tool (tech 1)
®.
- With the engine OFF, turn the ignition switch to the RUN position.
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze
Frame and Failure Records for reference. The Clear Info function will erase
the data.
- Record the DTC Freeze Frame and Failure Records.
- Drive the vehicle in 4th gear with the TCC engaged.
Is the TCC Slip Speed greater than the specified value for 7 seconds?
| 130 RPM
|
Go to Step 5
| Go to Diagnostic Aids
|
5
|
| • | Inspect the Torque Converter Clutch Solenoid Valve (TCC Sol. Valve)
for the following conditions: |
| • | Internal malfunction (such as sediment or damage) |
| • | Inspect the Torque Converter Clutch Pulse Width Modulation Solenoid
Valve (TCC PWM Sol. Valve) for the following conditions? |
| • | Internal malfunction (such as sediment or damage) |
Did you find a problem?
| --
|
Go to Step 14
|
Go to Step 6
|
6
|
| • | Inspect the 1-2 Shift Solenoid Valve (1-2 SS Valve) for the following
conditions: |
| • | Internal malfunction (such as sediment or damage) |
| • | Inspect the 2-3 Shift Solenoid Valve (2-3 SS Valve) for the following
conditions? |
| • | Internal malfunction (such as sediment or damage) |
Did you find a problem?
| --
|
Go to Step 14
|
Go to Step 7
|
7
| Inspect the valve body assembly for a stuck TCC signal valve.
Refer to Unit Repair.
Did you find a problem?
| --
|
Go to Step 14
|
Go to Step 8
|
8
| Inspect the torque converter assembly for the following conditions:
| • | Stator roller clutch not holding |
Did you find a problem?
| --
|
Go to Step 14
|
Go to Step 9
|
9
| Inspect the oil pump assembly for the following conditions:
| • | Stuck converter clutch valve |
| • | Converter clutch valve assembled backwards |
| • | Mispositioned converter clutch valve retaining ring |
| • | 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 problem?
| --
|
Go to Step 14
|
Go to Step 10
|
10
| 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 problem?
| --
|
Go to Step 14
|
Go to Step 11
|
11
| 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 problem?
| --
|
Go to Step 14
|
Go to Step 12
|
12
| 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 problem?
| --
|
Go to Step 14
|
Go to Step 13
|
13
| 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 problem?
| --
|
Go to Step 14
| Go to Diagnostic Aids
|
14
| In order to verify your repair, perform the following procedure:
- 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 TCC Slip Speed is -20 to +20 RPM
for at least 12 seconds. |
- Select Specific DTC. Enter DTC P1870.
Has the test run and passed?
| --
| System OK
| Begin the diagnosis again. Go to Step 1
|
