DTCS 37/38, TCC Brake Switch Stuck On/Off: Notes

Normally closed brake switch supplies a B+ signal on TCC brake switch signal circuit to PCM. When brakes are applied signal voltage is opened.

DTC 37 will set when:

TCC brake switch signal circuit is open.

* Vehicle speed is less than 5 MPH for greater than 6 seconds.

* Then vehicle speed is 5-20 MPH for greater than 6 seconds.

* Then vehicle speed is greater than 20 MPH for greater than 6 seconds.

* For a total of 7 times.

DTC 38 will set when:

TCC brake switch signal circuit has constant voltage.

* Vehicle speed is greater than 20 MPH for greater than 6 seconds.

* Then vehicle speed is 5-20 MPH for greater than 6 seconds.

* For a total of 7 times.

PCM will default to an incorrect brake signal can affect TCC scheduling. Also, an incorrect brake signal can inhibit 4th gear operation, if in hot mode. DTCS 37/38 will be stored in PCM memory, but will not turn on MIL.

NOTE: Test numbers refer to numbers on diagnostic chart.

This test checks for voltage at brake switch.
This test checks brake switch.
This test checks TCC brake switch signal circuit at PCM.