P0742

Circuit Description
The PCM energizes the TCC solenoid by creating a ignition voltage on circuit RED/YEL. When ignition voltage is energized by the PCM, the TCC solenoid stops converter signal oil from exhausting. This causes converter signal oil pressure to increase and move the TCC valve. The TCC solenoid will deenergize when the PCM no longer provides an ignition voltage. When the TCC solenoid is deenergized, it will exhaust fluid and release the TCC.
This DTC detects low torque converter slip when the TCC is commanded "off". This is a type "B" DTC.

Conditions For Setting The DTC
The following conditions occur once per TCC cycle, three consecutive times:
- No TP DTCs P0122 or P0123.
- No 055 DTCs P0722 or P0723.
- No TCC solenoid DTC P1860.
- TP angle is greater than 20%.
- Engine speed is greater than 500 rpm and less than 3000 rpm.
- Engine vacuum is between 0 and 70 kPa.
- Commanded gear is not 1st.
- Gear range is D4.
- TCC is commanded "off".
- No TCC stuck off DTC P1870
- TCC slip speed is between -20 and 40 rpm for 4 seconds.
- Vehicle speed is greater than 25 km/h (15 mph) and less than 120 km/h (75 mph).
- Speed ratio is greater than 0.9 and less than 1.8.

Action Taken When The DTC Sets
- The PCM will illuminate the Malfunction Indicator Lamp (MIL) and CHECK TRANS Lamp.
- Inhibit TCC engagement.

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 warmup 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
- If the TCC is mechanically stuck "on" with the parking brake applied and any gear range selected, the TCC fluid will mechanically apply the TCC, possibly causing an engine stall.

Test Description
The number below refers to the step number on the diagnostic chart:
3. This test checks the mechanical state of the TCC. (When the PCM commands the TCC solenoid "off', the slip speed should increase).





DTC P0742 Torque Converter Clutch (TCC) Circuit Stuck On