The TCC Stoplamp switch indicates the brake pedal status. The normally-closed TCC Stoplamp switch supplies a B+ signal on circuit 420 to the Transmission Control Module (TCM). The signal voltage circuit opens when the brakes are applied. The TCM uses the open signal voltage circuit in order to de-energize the Torque Converter Clutch Pulse Width Modulation Solenoid Valve (TCC PWM Sol. Valve) when the brakes are applied.
If the TCM detects an open TCC Stoplamp switch circuit during accelerations, then DTC 37 sets.
• | The following sequence of events occurs seven consecutive times: |
- | The vehicle speed is less than 8 km/h (5 mph) for 6 seconds. |
- | Then vehicle speed is 8 40 km/h (5 25 mph) for 6 seconds. |
- | Then the vehicle speed is greater than 40 km/h (25 mph) for 6 seconds. |
• | The TCM detects an open TCC Stoplamp switch/circuit (0 volts). |
• | The TCM does not illuminate the Malfunction Indicator Lamp (MIL). |
• | The TCM inhibits TCC. |
• | The TCM inhibits 4th gear if in hot mode. |
• | DTC 37 is stored in TCM history. |
• | The TCM clears the DTC from Current to History when the fault condition(s) no longer exist and the ignition switch is cycled OFF and then ON. |
• | A scan tool can clear the DTC from Current and History status. The TCM clears the DTC from the TCM history if the vehicle completes 40 ignition cycles without a failure reported. |
• | The TCM cancels the DTC default actions when the fault no longer exists and the ignition is cycled OFF and then ON. |
• | Inspect the wiring at the TCM, the TCC Stoplamp Switch and all other circuit connecting points for the following conditions: |
- | A bent terminal |
- | A backed out terminal |
- | A damaged terminal |
- | Poor terminal tension |
- | A chafed wire |
- | A broken wire inside the insulation |
- | Moisture intrusion |
- | Corrosion |
• | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
• | Ask about the customer's driving habits and any unusual driving conditions he or she might have, such as stop and go traffic or expressway driving. |
• | Inspect the brake switch for proper mounting and adjustment. |
• | Inspect for the most current calibration ID and the latest bulletins. |
The numbers below refer to the step numbers on the diagnostic table.
This step tests for TCC Stoplamp switch voltage to the TCM connector.
This step isolates the TCC Stoplamp switch as a source for setting the DTC.
This step tests for a short to ground in circuit 241 (ignition voltage) to the TCC Stoplamp switch.
This step tests for a short to ground in circuit 420, from the TCC Stoplamp switch to the TCM.
This step isolates the TCM as a source for causing the fuse to open.
Step | Action | Value(s) | Yes | No | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||||||
2 |
Important:: Before clearing the DTC's, record the Current and History DTC's information for reference. The Clear Info function erases the stored Current and History DTC from the TCM. Does the Scan Tool TCC Brake switch indicate CLOSED, when the brake pedal is not applied? | -- | Go to Diagnostic Aids | |||||||||||
3 |
Refer to General Electrical Diagnosis . Is the fuse open? | -- | ||||||||||||
Is the test lamp on? | -- | |||||||||||||
5 |
Is B + voltage indicated? | 10 - 13 volts | ||||||||||||
6 | Inspect circuit 241 for an open. Refer to General Electrical Diagnosis . Did you find and correct an open condition? | -- | -- | |||||||||||
Is the test lamp on? | -- | |||||||||||||
8 | Inspect circuit 420 for an open. Refer to General Electrical Diagnosis . Did you find and correct an open condition? | -- | -- | |||||||||||
9 | Replace the TCC/Stoplamp Switch. Refer to Stop Lamp Switch Replacement . Is the replacement complete? | -- | -- | |||||||||||
Does the fuse open with the brake pedal applied? | -- | |||||||||||||
11 | Inspect circuit 241 for a short to ground. Refer to General Electrical Diagnosis . Did you find and correct the short to ground condition? | -- | -- | |||||||||||
With the key in the RUN position, release the brake pedal. Does the fuse open when the brake pedal is released? | -- | Go to Diagnostic Aids | ||||||||||||
Does the fuse open? | -- | |||||||||||||
14 | Inspect circuit 420 (PPL) for a short to ground. Refer to General Electrical Diagnosis . Did you find and correct the short to ground condition? | -- | -- | |||||||||||
15 | Inspect the TCM terminals for shorted, corroded or weak connections. Did you find a condition? | -- | ||||||||||||
16 | Replace the TCM. Refer to DTC 51 PROM Error TCM Replacement. Is the replacement complete? | -- | -- | |||||||||||
17 | In order to verify your repair, perform the following procedure:
Does the TCC Brake Switch indicate Closed when the brake pedal is not applied, then indicate Open when the brake pedal is applied? | -- | Repair verified, exit DTC table | Begin Diagnosis again |