For 1990-2009 cars

### Circuit Description

The TCM can calculate the speed of the turbine in the torque converter by using the Engine Speed, the Output Speed and the Gear. If the TCC solenoid DTC is not set, and the TCM detects a slippage greater than a specific amount with the TCC commanded on, the TCM concludes that the TCC is stuck off (not engaged).

### Conditions For Running The DTC

• | The selector lever position is not equal to P, R, or N.

• | The transmission is not in default.

• | The engine speed is greater than 480 RPM.

• | DTC P0730 is not set.

• | The TCM commands the TCC on.

### Conditions For Setting The DTC

The absolute slippage between the engine speed and the calculated turbine speed is greater than 288 RPM.

### Action Taken When the DTC Sets

• | The TCM illuminates the Service Transmission Lamp (STL) and sends a MIL Request to the ECM on the second consecutive drive trip that the diagnostic runs and fails. The ECM then illuminates the MIL.

• | The ECM records the operating conditions in the Freeze Frame at the time of the MIL Request from the TCM.

• | The transmission operates in the Default Mode.

### Conditions for Clearing the MIL/DTC

• | The TCM turns off the STL as soon as the fault is no longer present.

• | The ECM turns off the MIL after three consecutive drive trips during which the TCM sends no MIL Request.

• | A History DTC clears after forty consecutive warm-up cycles, if no failures are present by this diagnostic or any other emission related diagnostic.

• | The scan tool clears the MIL/DTC.

#### DTC P1870 - TCC Stuck Off

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
2 | Is DTC P0730 or P0743 also set? | -- | Go to The applicable DTC | Go to Functional Test