Powertrain Controls - ECM/PCM

DTC 37/38 TCC Brake Switch Stuck "ON"/TCC Brake Switch Stuck "OFF":

TCC Brake Switch:

CIRCUIT DESCRIPTION
The normally closed brake switch supplies a B+ signal on CKT 420 to the Transmission Control Module (TCM). The signal voltage drops to 0 volt when the Torque Converter Clutch (TCC) brake switch is opened (brake pedal applied).

DTC 38 WILL SET WHEN
^ CKT 420 has constant voltage.
- Vehicle speed is greater than 20 mph for greater than 6 seconds.
- Then vehicle speed is between 5 mph and 20 mph for greater than 6 seconds.
- For a total of seven times.

ACTION TAKEN (TCM will default to)
^ No fourth gear in hot mode.
^ No TCC.

DTC 38 WILL CLEAR WHEN
Fault condition no longer exists.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks for voltage at the brake switch.
2. This test checks the brake switch.
3. This test checks CKT 420 at the TCM.

DIAGNOSTIC AIDS
^ Refer to "TCM Intermittent Diagnostic Trouble Code or Performance." PCM/TCM Intermittent Diagnostic Trouble Code or Performance
^ Check customer driving habits and/or unusual traffic conditions (i.e., stop and go, expressway traffic).