Code 67, TCC Solenoid Circuit Check: Notes

The TCC solenoid is a normally open exhaust valve. The PCM will engage the solenoid by grounding circuit No. 422 with an internal quad-driver. The PCM continually monitors voltage on TCC circuit for either low or high voltage, depending on the commanded state of the circuit. Code 67 will set if a fault is detected.

For example, If the PCM commands the TCC solenoid on, the voltage on that circuit should drop when the solenoid is grounded. If voltage stays up for 2 seconds, Code 67 will set. If solenoid is off, the voltage on that circuit should remain higher. If voltage drops for 2 seconds, Code 67 will set. When code is set, no TCC will occur and no 4th gear in hot mode.

1. This test checks TCC solenoid and the internal transmission harness for short circuits.
2. This test checks for power, from the ignition through the fuse, to the TCC solenoid.
3. This test ensures circuit No. 422 is not shorted to ground.
4. This test checks ability of PCM to ground or control TCC solenoid.