P1870

DTC P1870 Transmission Component Slipping (TCC Stuck Off)





Circuit Description
The PCM monitors the difference in engine speed and transmission output speed. In D3 drive range with the TCC engaged, the engine speed should closely match transmission output speed.
This DTC detects excessive TCC slip when the TCC is engaged. This is a type "B" DTC.

Conditions For Setting The DTC
The following conditions are met for three TCC cycles with reported excessive TCC slip conditions.
- No OSS DTCs P0722 or P0723.
- No shift solenoid A DTCs P0751 or P0752 or P0753.
- No shift solenoid B DTCs P0756 or P0757 or P0758.
- No TCC solenoid DTCs P0742 or P1 860 or P1870.
- Engine speed is between 1000 and 3500 rpm for 0.5 seconds.
- Engine vacuum is between 0 and 70 kPa.
- Gear range is D4.
- TP angle is greater than 10%.
- TFT is between 20° and 150°C (68° and 302°F).
- TCC slip speed is between 250 rpm and 800 rpm for 3 times 7 seconds.
- Vehicle speed is between 25 km/h (15 mph) and 255 km/h (158 mph).
- Speed ratio is between 0.6 and 0.95.
- 13% < TPS < 99%.
- 50 < Engine Torque < 300 Nm.
- Low (0.8) < TCC capacity < hi (0.99) for 5 seconds.

Action Taken When The DTC Sets
- Only stored in memory.
- For lamp illuminate refer to Type B - Types Of Diagnostic Trouble Codes (DTCs)

Conditions For Clearing The MIL/DTC
- The PCM will turn off the MIL and CHECK TRANS Lamp after three consecutive ignition cycles without a failure reported.
- The DTC can be cleared from the PCM history by using a scan tool.
- The DTC will be cleared from history when the vehicle has achieved 40 warm-up cycles without a failure reported.
- The PCM will cancel the DTC default actions when the fault no longer exists and the ignition is cycled "off" long enough to power down the PCM.

Diagnostic Aids
- Range switch malfunction could set a DTC P1870.
- A mechanical failure of the shift solenoids, TCC solenoid, or TCC PWM solenoid could set a DTC P1870.
- Internal transmission failures may set a DTC P1870.
- An intermittent or incorrect engine speed signal may set a DTC P1870.

Test Description
The numbers below refer to the step numbers on the diagnostic chart:
2. This test checks the indicated range signal to the actual selected range. A faulty switch could set a DTC P1870.
3. This test checks the torque converter for slippage while in a commanded lockup state.





Range Switch Logic Table





DTC P1870 Transmission Component Slipping (TCC Stuck Off)