P1870

Diagnostic Chart:

Description:

Circuit Description

The Powertrain Control Module (PCM) monitors the Torque Convener Clutch (TCC) slip by calculating the difference between the engine speed and the
transmission output shaft speed.

If the PCM detects an excessive amount of slip when the TCC is engaged, then DTC P1870 sets. DTC P1870 is a type B DTC.

Conditions for Setting the DTC

^ No Throttle Position (TP) DTCs P0122 or P0123.

^ No Vehicle Speed Sensor (VSS) DTCs P0502 or P0503.

^ No 1-2 Solenoid Performance DTC P0751.

^ No 1-2 Solenoid Electrical DTC P0753.

^ No 2-3 Solenoid Performance DTC P0756.

^ No 2-3 Solenoid Electrical DTC P0758.

^ No TCC PWM Solenoid Electrical DTC P1860.

^ No TCC Enable Solenoid Electrical DTC P0740.

^ The engine speed is greater than 500 RPM for 5 seconds.

^ Not in fuel shut off.

^ The throttle angle is 8.5 - 35%.

^ The speed ratio is 0.6 - 0.89.

^ The engine speed is 800 - 5000 RPM.

^ The vehicle speed is 56 - 121 km/h (35 - 75 mph).

^ The transmission is not in first gear.

^ The transmission gear range is D4.

^ The transmission fluid temperature is 20 - 130°C (68 - 266°F).

^ The engine torque is 68 - 230 N.m (50 - 170 ft lbs.).

^ The TCC is commanded ON and at maximum apply for 4 seconds.

^ The TCC slip is 200-1500 RPM for 5 seconds.

^ The above conditions must occur three times with the TCC commanded OFF between each occurrence.

Action Taken When the DTC Sets

^ The PCM inhibits TCC operation.

^ The PCM inhibits 4th gear, if the transmission is in the hot mode.

^ The PCM illuminates the Malfunction Indicator Lamp (MIL) after two consecutive trips with a failure reported..

Conditions for Clearing the MIL/DTC

^ The PCM turns OFF the MIL after three consecutive ignition cycles 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

^ Ensure that the vehicle's final drive ratio matches the PCM's calibration.

^ Ensure that the transmission will shift through all four gears with the gear select lever in the D4 range.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

4. This step inspects the modulator assembly, which could cause P1870 to set.

5. These are the components that could cause P1870 to set.