DTC P1870 Transmission Component Slipping Gas
Circuit Description
The Vehicle Control Module (VCM) monitors the engine speed, and the transmission output shaft speed. The VCM calculates turbine shaft speed and Torque Converter Clutch (TCC) slip speed by using inputs from the transmission Input Shaft Speed (ISS) Sensor, Transmission Output Shaft Speed (OSS) Sensor and other transmission components. The forward clutch housing is used as the ISS Sensor rotor. Whenever the TCC is engaged, engine speed and turbine speed will closely match, indicating low TCC slip speed. In D3 with the TCC engaged, calculated transmission component slip can only occur in the torque converter. In D4 Overdrive with the TCC engaged, transmission component slip can occur in the TCC or the fourth clutch assembly.
If the VCM detects an excessive TCC slip speed in D4 Overdrive, when the TCC should be engaged, then DTC P1870 sets. DTC P1870 is a type D DTC. For California emissions vehicles, DTC P1870 is a type B DTC.
Conditions for Setting the DTC
The following conditions occur 3 times for 10 seconds:
| • | No MAP DTCs P0101, P0102 or P0103. |
| • | No MAF DTCs P0106, P0107 or P0108. |
| • | No engine speed DTCs P0335, P0336, P0337, or P0338. |
| • | No TP Sensor DTCs P0121, P0122, or P0123. |
| • | No OSS DTC P0502. |
| • | No A/T ISS sensor DTCs P0716 or P0717. |
| • | No TCC PWM Sol. Valve DTCs P0741, P0742 or P1860. |
| • | No 1-2 SS Valve DTCs P0751 or P0753. |
| • | No 2-3 SS Valve DTCs P0756 or P0758. |
| • | No TFP Val. Position Sw. DTCs P1810. |
| • | The engine speed is greater than 475 RPM for 7 seconds and not in fuel cutoff mode. |
| • | The TP Sensor is 7-80%. |
| • | Engine speed is 1250-5500 RPM . |
| • | The engine vacuum is 0-105 kPa. |
| • | The TFT is 20° to 130°C (68°-266°F). |
| • | Vehicle speed is 56.3-177 Kp/h (35-110 MPH) |
| • | TFP Val. Position Sw. indicates D4. |
| • | Speed ratio is 1.30-0.70 for 5.7L and 7.4L, or 1.69-0.70 for 4.3L. |
| • | The engine torque is 100 N·m (80 lb ft) to the following: |
| - | 94.8-542 N·m (70-400 lb ft) 5.7L |
| - | 108.4-677.5 N·m (80-500 lb ft) 7.4L. |
| • | The TCC is commanded ON for 5 seconds or more. |
| • | TCC duty cycle is greater than 95%. |
| • | The VCM detects a slip speed of: |
| - | 120-550 RPM. 5.7L |
| - | 110-550 RPM. 7.4L |
Action Taken When the MIL/DTC Sets
| • | The VCM illuminates the Malfunction Indicator Lamp (MIL) for California emissions vehicles. |
| • | The VCM commands maximum line capacity. |
| • | The VCM inhibits the TCC engagement. |
| • | The VCM inhibits 4th gear if in hot mode. |
| • | The VCM freezes shift adapts. |
| • | DTC 1870 is stored in VCM History. |
Conditions for Clearing the DTC
| • | For California emissions vehicles, the VCM turns OFF the MIL after three consecutive trips without a failure reported. |
| • | A scan tool can clear the DTC from the VCM history. The VCM clears the DTC from the VCM history if the vehicle completes 40 warm-up cycles without a failure reported. |
| • | The VCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the VCM. |
Diagnostic Aids
| • | A TFP Val. Position Sw. malfunction can set DTC P1870. |
| • | A mechanical failure of the shift solenoids or TCC PWM Sol. Valve can set DTC P1870. |
| • | Internal transmission failures can result in a DTC P1870. |
| • | Sticking or contaminated shift valves may cause intermittent slipping in D4. |
| • | First diagnose and clear any engine DTCs or TP Sensor codes that are present. Then inspect for any transmission DTCs that may have reset. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the indicated range signal to the actual selected range. A faulty TFP Valve Position Switch can set a DTC P1870.
-
This step tests for excessive TCC slip speed while in a commanded TCC lock-up state and in fourth gear; and confirms that the fault is present.
-
This step tests for excessive TCC slip speed while in a commanded TCC lock-up state and in third gear.
-
This step tests for a sticking TCC shift valve.
-
This step tests for proper transmission line pressure.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check (5.7L) or Powertrain On Board Diagnostic (OBD) System Check (7.4L) | |||||||||
2 | Perform the Transmission Fluid Checking Procedure. Refer to Transmission Fluid Check . Did you perform the procedure? | -- | Go to Transmission Fluid Check | |||||||||
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 stored Freeze Frame and Failure Records from the VCM. Does each selected transmission range match the scan tool TFP Switch A/B/C display? (Refer to the Range Signal table.) | -- | |||||||||||
Drive the vehicle under the following conditions:
At any time is the TCC Slip Speed greater than the specified value for 10 seconds? | 120 RPM (5.7L) 110 RPM (7.4L) | Go to Diagnostic Aids | ||||||||||
Drive the vehicle under the following conditions:
At any time is the TCC Slip Speed greater than the specified value for 10 seconds? | 120 RPM (5.7L) 110 RPM (7.4L) | |||||||||||
Repeat the procedure in step 4. Drive the vehicle under the following conditions:
Is the TCC slip speed greater than the specified value? | 120 RPM (5.7L) 110 RPM (7.4L) | |||||||||||
7 | Refer to the System Diagnosis table: Torque Converter Clutch Slipping . Did you find and correct the condition? | -- | -- | |||||||||
Refer to Line Pressure Check . Is the line pressure within specifications? | -- | Go to the applicable System Diagnosis Table: | ||||||||||
9 |
Refer to Changing the Fluid and Filter, in On-Vehicle Service. Is the fluid or the pan contaminated? | -- | Go to Transmission Overhaul Procedure, in Unit Repair | |||||||||
10 |
Did you find the condition? | -- | ||||||||||
11 | Inspect the following components for contamination or sticking.
Did you find the condition? | -- | Go to Transmission Overhaul Procedure, in Unit Repair | |||||||||
12 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
DTC P1870 Transmission Component Slipping Diesel
Circuit Description
The Powertrain Control Module (PCM) monitors the engine speed, and the transmission output shaft speed. The PCM calculates turbine shaft speed and Torque Converter Clutch (TCC) slip speed by using inputs from the transmission Input Shaft Speed (ISS) Sensor, Transmission Output Shaft Speed (OSS) Sensor and other transmission components. The forward clutch housing is used as the ISS Sensor rotor. Whenever the TCC is engaged, engine speed and turbine speed will closely match, indicating low TCC slip speed. In D3 with the TCC engaged, calculated transmission component slip can only occur in the torque converter. In D4 Overdrive with the TCC engaged, transmission component slip can occur in the TCC or the fourth clutch assembly.
If the PCM detects an excessive TCC slip speed in D4 Overdrive, when the TCC should be engaged, then DTC P1870 sets. DTC P1870 is a type D DTC. For California emissions vehicles, DTC P1870 is a type B DTC.
Conditions for Setting the DTC
| • | No MAP DTCs P0106, P0107 or P0108. |
| • | No Engine Speed DTC P0335 |
| • | No A/T ISS Sensor DTCs P0716 or P0717 |
| • | No OSS Sensor DTCs P0722 or P0723 |
| • | No TCC PWM Sol. Valve DTCs P0741, P0742, or P1860 |
| • | No 1-2 SS Valve DTCs P0751 or P0753 |
| • | No 2-3 SS Valve DTCs P0756 or P0758 |
| • | No TFP Val. Position Sw. DTCs P1810 |
| • | The gear range is D4. |
| • | The APP Angle is 12-80%. |
| • | The TFT is +20° to +130°C (68°-266°F). |
| • | The engine speed is 1200-3750 RPM. |
| • | System voltage is 9.0-16.0 volts. |
| • | The vehicle speed is 48-176 km/h (30-110 mph). |
| • | The engine torque is 75-352 N·m (60-265 lb ft). |
The above conditions are met, with 4th gear commanded and the TCC ON and one of the following conditions occur:
Condition 1 (after 3 Occurrences)
The PCM detects a slip speed of 120-525 RPM for greater than 5.0 seconds.
Condition 2 (in the following sequence for one Occurrence)
- The PCM detects a TCC Slip Speed of 110-500 RPM for 10 seconds.
- The PCM detects a TCC Slip Speed of 110-500 RPM for 10 seconds.
- The PCM detects a TCC Slip Speed of 110-500 RPM for 10 seconds.
| • | The PCM commands maximum line pressure. |
| • | The PCM freezes shift adapts. |
| • | The PCM commands the TCC OFF for 1.5 seconds. |
| • | The PCM commands the TCC ON. |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | The PCM commands maximum line pressure. |
| • | The PCM inhibits the TCC engagement. |
| • | The PCM inhibits 4th gear if in hot mode. |
| • | The PCM freezes shift adapts. |
| • | DTC P1870 is stored in PCM History. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive trips without a failure reported. |
| • | A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | A TFP Val. Position Sw. malfunction can set DTC P1870. |
| • | A mechanical failure of the shift solenoids or TCC PWM Sol. Valve can set DTC P1870. |
| • | Internal transmission failures can result in a DTC P1870. |
| • | Sticking shift valves or contamination may cause intermittent slipping in D4. |
| • | First diagnose and clear any engine DTCs that are present. Then inspect for any transmission DTCs that may have reset. |
| • | DTC P1860 TCC PWM Solenoid Circuit Electrical can cause a DTC 1870 to set. Diagnose the electrical codes first. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the indicated range signal to the actual selected range. A faulty TFP Valve Position Switch can set a DTC P1870.
-
This step tests for excessive TCC slip speed while in a commanded TCC lock-up state and in fourth gear; and confirms that the fault is present.
-
This step tests for excessive TCC slip speed while in a commanded TCC lock-up state and in third gear.
-
This step tests for a sticking TCC shift valve.
-
This step tests for proper transmission line pressure.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||||
2 | Perform the Transmission Fluid Checking Procedure. Refer to Transmission Fluid Check . Did you perform the procedure? | -- | Go to Transmission Fluid Check | |||||||||
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM. Does each selected transmission range match the scan tool TFP Switch A/B/C display? (Refer to the Range Signal table.) | -- | |||||||||||
Drive the vehicle under the following conditions:
At any time is the TCC Slip Speed greater than the specified value for 6 seconds? | 120 RPM | Go to Diagnostic Aids | ||||||||||
Drive the vehicle under the following conditions:
At any time is the TCC Slip Speed greater than the specified value for 6 seconds? | 110 RPM | |||||||||||
Repeat the procedure in step 4. Drive the vehicle under the following conditions:
Is the TCC slip speed greater than the specified value? | 120 RPM | |||||||||||
7 | Refer to the System Diagnosis table: Torque Converter Clutch Slipping . Did you find and correct the condition? | -- | -- | |||||||||
Refer to Line Pressure Check . Is the line pressure within specifications? | -- | Go to the applicable System Diagnosis Table: | ||||||||||
9 |
Refer to Changing the Fluid and Filter, in On-Vehicle Service. Is the fluid or the pan contaminated? | -- | Go to Transmission Overhaul Procedure, in Unit Repair | |||||||||
10 |
Did you find the condition? | -- | ||||||||||
11 | Inspect the following components for contamination or sticking.
Did you find the condition? | -- | Go to Transmission Overhaul Procedure, in Unit Repair | |||||||||
12 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
