P1870

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.

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Inspection Procedure


Conditions For Setting The DTC
The following conditions are met for three TCC cycles with reported excessive TCC slip conditions.
- No TPS DTCs P0122 or P0123.
- No OSS DTCs P0722 or P0723.
- No shift solenoid A DTCs P0751 or P0753.
- No shift solenoid B DTCs P0756 or P0758.
- No TCC solenoid DTC P1860.
- No TCC solenoid DTC P0742.
- Engine speed is between 800 and 3,360 rpm.
- Engine vacuum is between 0 and 70 kPa.
- Gear range is D4.
- 13%< TPS <99%.
- TFT is between 20° and 141°C (68° and 286°F).
- TCC slip speed is between 250 rpm and 800 rpm for 3 times 7 seconds.
- Vehicle speed is between 38 km/h (24 mph) and 110 km/h (69 mph).
- Speed ratio is between 0.6 and 0.95.
- ECCC is ON.
- 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 DTC type definition (type B).

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 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 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