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

### 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 or open (with the brake pedal pressed).

### 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 may be other possible causes of this malfunction:

- | The TCC/antilock 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 ABS Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check - ABS
2 |

1. Install a scan tool.
2. Use the scan tool in order to observe the brake travel switch ON/OFF transition in the data list.

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 | Use the J 39200 in order to measure the resistance between the J 38716 pinout box terminal 1 and terminal 5. Is the resistance less than the specified value? | 2 ohms | Go to Step 14 | Go to Step 5
5 | Use the J 39200 in order to measure the resistance between the J 38716 pinout box terminal 1 and terminal 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. Use the J 39200 in order to 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. Press the brake pedal over 40% travel and hold.
2. Use the J 39200 in order to measure the resistance between the brake travel switch terminal C and terminal 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. Use the J 39200 in order to measure the voltage between the J 38716 pinout box terminal 1 and terminal 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. Use the J 39200 in order to measure the resistance between the J 38716 pinout box terminal 5 and terminal 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 in order to clear DTCs.
3. Test drive the vehicle.

Does the DTC C1272 reset?

--

Go to Step 21

Go to Diagnostic System Check - ABS

11 | Check the brake travel switch adjustment. 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. Use the J 39200 in order to measure the voltage between the J 38716 pinout box terminal 1 and terminal 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. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
14 | Repair the short to ground in CKT 848. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
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 - ABS | --
16 | Replace the brake travel switch. Refer to Brake Release Switch Replacement in Cruise Control. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
17 | Repair the brake travel switch. Refer to Brake Release Switch Adjustment in Cruise Control. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
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 - ABS | --
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 - ABS | --
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 - ABS | --
21 | Replace the EBCM/EBTCM. Refer to Electronic Brake and Traction Control Module Replacement Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --