Torque Converter Clutch: Testing and Inspection

Chart C-8A-1 - Transmission Converter Clutch (TCC):

Wiring Diagram for Chart C-8A-1 & C-8A-2 - Transmission Converter Clutch (TCC):

CHART C-8A-1 & C-8A-2 - TRANSMISSION CONVERTER CLUTCH (TCC)

Test Description:

1. Checks for proper closing of 3rd gear switch. Light should come "ON" when switch closes.

2. Checks to see if ECM completes ground to energize TCC solenoid. Light should go "OUT".

3. This increases throttle opening to increase TPS output. If TPS output is too low, the clutch won't apply. On some applications, running free doesn't require enough throttle opening to allow the transmission to shift.

4. Checks for low voltage at TPS input at ECM. At WOT, voltage should be approximately 5V (ref.). Too low a TPS output could prevent the transmission from shifting.


5. Checks for VSS signal at ECM. VSS signal is necessary to engage TCC.


6. Checks for open in circuits to terminals "N" and "17". The ECM supplies 12 volts to these terminals through a resistor. Normally both circuits should have low voltage readings since they involve normally closed circuits with vehicle stopped. An open circuit would give a reading of about 12 volts.


7. Switch(es) open when transmission up shifts. Checks that transmission circuit functions normally by voltage going high (near battery voltage) as switches open.

Chart C-8A-2 - Transmission Converter Clutch (TCC):

Wiring Diagram for Chart C-8A-1 & C-8A-2 - Transmission Converter Clutch (TCC):

Test Description (Cont'd)

8. Checks for ground in circuit to ECM terminal "P". Normally light should be "OFF".

9. Checks for ignition voltage to terminal "A" of transmission connector. Light should normally be "ON".


10. Checks for complete circuit from ignition to ground via TCC test terminal. Normally light should go "ON" if harness is good.