For 1990-2009 cars
ABS Components
Cell 44: ABS/TCS Switch, Isolation Valve Solenoids, and PCM
Cell 10: F/PMP, HZRD/STOP and INTR LP Fuses
Cell 110: Turn/Hazard Switch and Stoplamp/BTSI Switch
Cell 110: Turn/Hazard Switch and Stoplamp/BTSI Switch

### 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 Step 2 | Go to Diagnostic System Check
2 |

1. Connect the scan tool.
2. Using the scan tool, under DATA LIST, check for brake travel switch ON/OFF transition.

Is the brake switch operating properly?

--

Go to Step 10

Go to Step 3

3 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the brake travel switch connector.
3. Disconnect the EBCM/EBTCM harness connector.
4. Install the J 38716 pinout box to the EBCM/EBTCM wiring harness connector.
5. Use the J 39200 in order to measure the resistance between the J 38716 pinout box terminal 1 and a known good ground.

Is the resistance less than the specified value?

2 ohms

Go to Step 4

Go to Step 13

4 | Measure the resistance between the J 38716 pinout box terminals 1 and 5. Is the resistance less than the specified value? | 2 ohms | Go to Step 14 | Go to Step 5
5 | Measure the resistance between the J 38716 pinout box terminals 1 and 26. Is the resistance less than the specified value? | 2 ohms | Go to Step 15 | Go to Step 6
6 |

1. Disconnect the brake travel switch wiring harness connector.
2. Measure the resistance between the brake travel switch terminals C and D.

Is the resistance less than the specified value?

2 ohms

Go to Step 7

Go to Step 11

7 |

1. Depress the brake pedal over 40% travel and hold.
2. Measure the resistance between the brake travel switch terminals C and D.

Is the resistance less than the specified value?

2 ohms

Go to Step 11

Go to Step 8

8 |

1. Reconnect the brake travel switch harness connector.
2. Turn the ignition switch to the RUN position.
3. Measure the voltage between the J 38716 pinout box terminals 1 and 5.

Is the voltage greater than the specified value?

1 V

Go to Step 12

Go to Step 9

9 |

1. Turn the ignition switch to the OFF position.
2. Measure the resistance between the J 38716 pinout box terminals 5 and 26.

Is the resistance less than the specified value?

2 ohms

Go to Step 21

Go to Step 20

10 |

1. Check for proper terminal contact at the EBCM/EBTCM and the brake travel switch.
2. Use the scan tool to clear all DTCs.
3. Test drive the vehicle.

Does the DTC C1272 reset?

--

Go to Step 21

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. | -- | Go to Step 16 | Go to Step 17
12 |

1. Press the brake pedal over 40% travel and hold.
2. Measure the voltage between the J 38716 pinout box terminals 1 and 26.

Is the voltage greater than the specified value?

1 V

Go to Step 18

Go to Step 19

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 | --