Circuit Description
| • | The EBCM/EBTCM monitors the brake pedal position using the brake travel switch. The switch, normally closed, opens when the brake pedal is pressed by 40 percent. |
| • | During most ABS braking conditions the EBCM/EBTCM turns ON the pump motor, replenishing the BPMV reservoir and applying fluid pressure to the master cylinder. This causes the brake pedal to rise gradually. The EBCM/EBTCM turns OFF the pump motor when the brake pedal height rises sufficiently to close the brake travel switch. |
Conditions for Setting the DTC
The DTC C1272 sets when the EBCM/EBTCM detects that the brake travel switch CKT 848 is shorted to ground (with the brake pedal pressed) or open.
Action Taken When the DTC Sets
The following actions are taken when the DTC sets:
| • | DTC C1272 is stored. |
| • | The ABS is disabled. |
| • | The ANTILOCK indicator lamp is turned on. |
Conditions for Clearing the DTC
The DTC will clear under following conditions:
| • | Conditions for the malfunction are no longer present. Use the scan tool Clear DTCs function. |
| • | 100 ignition switch key cycles have passed without detecting any malfunctions |
Diagnostic Aids
| • | The following conditions are other possible causes of this malfunction: |
| - | The ABS/TCC switch circuit is open or shorted to ground |
| - | The BPMV fluid level switch circuit is shorted to ground |
| - | The ABS Pump Motor Pressure Switch circuit is shorted to ground |
| • | Perform a thorough inspection of the wiring and the connectors. |
| • | Failure to carefully inspect wiring may result in a misdiagnosis. A misdiagnosis may result in replacing parts without repairing the malfunction. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Diagnostic System Check | |
2 |
Is the brake switch operating properly? | -- | ||
3 |
Is the resistance less than the specified value? | 2 ohms | ||
4 | Measure the resistance between the J 38716 pinout box terminals 1 and 5. Is the resistance less than the specified value? | 2 ohms | ||
5 | Measure the resistance between the J 38716 pinout box terminals 1 and 26. Is the resistance less than the specified value? | 2 ohms | ||
6 |
Is the resistance less than the specified value? | 2 ohms | ||
7 |
Is the resistance less than the specified value? | 2 ohms | ||
8 |
Is the voltage greater than the specified value? | 1 V | ||
9 |
Is the resistance less than the specified value? | 2 ohms | ||
10 |
Does the DTC C1272 reset? | -- | Go to Diagnostic System Check | |
11 | Check the brake travel switch adjustment. Refer to Brake Release Switch Adjustment in Cruise Control. Is the brake travel switch properly adjusted. | -- | ||
12 |
Is the voltage greater than the specified value? | 1 V | ||
13 | Repair the short to ground in CKT 1451. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
14 | Perform diagnostics for DTC C1273 and begin Step 3. Refer to DTC C1273 BPMV Fluid Level Switch Circuit Malfunction . Is the diagnosis complete? | -- | -- | -- |
15 | Repair the short to ground in CKT 853. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
16 | Replace the brake travel switch. Refer to Brake Release Switch Replacement in Cruise Control. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
17 | Repair the brake travel switch. Refer to Brake Release Switch Replacement in Cruise Control. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
18 | Repair the short to voltage in CKT 853. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
19 | Repair the short to voltage in CKT 848. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
20 | Repair the open or high resistance in CKT 848. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
21 | Replace the EBCM/EBTCM. Refer to Electronic Brake and Traction Control Module Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | -- |
