For 1990-2009 cars

## DTC C0161 North America

### Circuit Description

When the brake pedal is depressed, the contacts on the brake light switch close to illuminate the brake lights. Battery voltage is also applied to terminal 16 of the electronic brake control module (EBCM), which signals the antilock brake system (ABS) controller that the brakes are applied and ABS may be needed. Without this, signals from a wheel speed sensor that may indicate a need for ABS intervention are questionable. When the brake pedal is not depressed, the EBCM terminal 16 is grounded through the brake lights.

This procedure will check whether there is no output or constant output from the brake light switch and will determine the cause as a faulty switch or a problem in the circuitry.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0161 Stop Lamp Switch Circuit Open

### Conditions for Running the DTC

• | Vehicle speed is greater than 6 km/h (4 mph) with the brake pedal not applied

| or

• | Vehicle speed is greater than 15 km/h (9 mph) and the brake pedal is actuated.

### Conditions for Setting the DTC

• | The ground connection or the positive connection at the EBCM has failed.

• | There is an open, short to ground, or short to positive in the vehicle wiring.

• | The brake light switch has failed.

### Action Taken When the DTC Sets

The system records a DTC C0161. The ABS and EBD operation is enabled and the ABS/EBD warning lamp doesn't turn ON.

### Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

### Diagnostic Aids

Inspect wiring and connectors carefully and thoroughly. Failure to do so could result in misdiagnosis, causing part replacement with reappearance of the malfunction.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This simple test will isolate the problem to the fuse-brake light switch-splice 301 area or the splice 301-EBCM area.

2. This is the 1st step in identifying an open, a short to ground, a short to voltage, or a faulty brake light switch.

3. This step begins the process of finding an open, a defective connector, or a faulty EBCM.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Step on the brake pedal. Do the brake lights come on at all? | -- | Go to Step 4 | Go to Step 3
3 | Remove your foot from the brake pedal. Do the lights stay on continuously? | -- | Go to Step 9 | Go to Step 12
4 | Inspect fuse EF13 in the engine compartment fuse block. Is fuse EF13 open? | -- | Go to Step 5 | Go to Step 7
5 |

1. Replace fuse EF13.
2. Inspect the new fuse.

Is the new fuse open?

--

Go to Step 6

Go to Step 8

6 |

1. Repair the short to ground in the brake light circuitry.
2. Install a new fuse EF13.

Did you complete the action?

--

Go to Step 17

--

7 | Repair the open in the brake light switch circuit OG/BK from terminal 6 of connector C102 at the engine fuse block to the brake light switch and circuit L-BU from terminal 11 of splice S301. Did you complete the repair? | -- | Go to Step 17 | --
8 | Inspect for functioning of the brake lights and the antilock brake system (ABS) system. Did you complete the action? | -- | Go to Step 17 | --
9 | Inspect the brake lamp switch adjustment. Refer to Stop Lamp Switch Adjustment . Did the switch adjustment correct the condition? | -- | Go to Step 11 | Go to Step 10
10 | Replace the brake lamp switch. Did you complete the repair? | -- | Go to Step 17 | --
11 | Repair the short to voltage in the circuit YE between the brake light switch, splice S301, the brake lights, the center high-mounted stop lamp, and the ABS wiring harness connector at the electronic brake control module (EBCM) terminal 16. Did you complete the repair? | -- | Go to Step 17 | --
12 |

1. Disconnect the EBCM connector.
2. Measure voltage between pins 16 and 13 of the EBCM harness connector.
3. Have an assistant step on the brake pedal.

Does the voltage measure within the specified range?

11-14 V

Go to Step 14

Go to Step 13

13 |

1. Examine the connection between the connector and the EBCM terminals 16 and 13.
2. Examine the connection at terminal 1 of connector C110.
3. Examine the wiring of circuit L-BU between splice S301 and terminal 14 of the EBCM connector for an open condition.
4. Examine the wiring between ground G106 and terminal 13 of the EBCM connector.
5. Repair the broken wire or the defective connector terminal, or replace the connector, the wiring harness as required.

Did you complete the repair?

--

Go to Step 17

--

14 | Inspect the interface between the EBCM connector and the EBCM. Is there damage at the interface? | -- | Go to Step 15 | Go to Step 16
15 | Repair the connector or replace the wiring harness or the EBCM as required. Did you complete the repair? | -- | Go to Step 17 | --
16 | Replace the EBCM. Did you complete the replacement? | -- | Go to Step 17 | --
17 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK

## DTC C0161 Except North America

### Circuit Description

When the brake pedal is depressed, the contacts on the brake light switch close to illuminate the brake lights. Battery voltage is also applied to terminal 41 of the electronic brake control module (EBCM), which signals the antilock brake system (ABS) controller that the brakes are applied and ABS may be needed. Without this, signals from a wheel speed sensor that may indicate a need for ABS intervention are questionable. When the brake pedal is not depressed, the EBCM terminal 41 is grounded through the brake lights.

This procedure will check whether there is no output or constant output from the brake light switch and will determine the cause as a faulty switch or a problem in the circuitry.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0161 Stop Lamp Switch Circuit Open

### Conditions for Running the DTC

• | Vehicle speed is greater than 6 km/h (4 mph) with the brake pedal not applied

| or

• | Vehicle speed is greater than 15 km/h (9 mph) and the brake pedal is actuated.

### Conditions for Setting the DTC

• | The ground connection or the positive connection at the EBCM has failed.

• | There is an open, short to ground, or short to positive in the vehicle wiring.

• | The brake light switch has failed.

### Action Taken When the DTC Sets

The system records a DTC C0161. The ABS and EBD operation is enabled and the ABS/EBD warning lamp doesn't turn ON.

### Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

### Diagnostic Aids

Inspect wiring and connectors carefully and thoroughly. Failure to do so could result in misdiagnosis, causing part replacement with reappearance of the malfunction.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This simple test will isolate the problem to the fuse-brake light switch-splice 301 area or the splice 301-EBCM area.

2. This is the 1st step in identifying an open, a short to ground, a short to voltage, or a faulty brake light switch.

3. This step begins the process of finding an open, a defective connector, or a faulty EBCM.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Step on the brake pedal. Do the brake lights come on at all? | -- | Go to Step 4 | Go to Step 3
3 | Remove your foot from the brake pedal. Do the lights stay on continuously? | -- | Go to Step 9 | Go to Step 12
4 | Inspect fuse EF13 in the engine compartment fuse block. Is fuse EF13 open? | -- | Go to Step 5 | Go to Step 7
5 |

1. Replace fuse EF13.
2. Inspect the new fuse.

Is the new fuse open?

--

Go to Step 6

Go to Step 8

6 |

1. Repair the short to ground in the brake light circuitry.
2. Install a new fuse EF13.

Did you complete the action?

--

Go to Step 17

--

7 | Repair the open in the brake light switch circuit OG/BK from terminal 6 of connector C102 at the engine fuse block to the brake light switch and circuit L-BU from terminal 11 of splice S301. Did you complete the repair? | -- | Go to Step 17 | --
8 | Inspect for functioning of the brake lights and the antilock brake system (ABS) system. Did you complete the action? | -- | Go to Step 17 | --
9 | Inspect the brake lamp switch adjustment. Refer to Stop Lamp Switch Adjustment . Did the switch adjustment correct the condition? | -- | Go to Step 11 | Go to Step 10
10 | Replace the brake lamp switch. Did you complete the repair? | -- | Go to Step 17 | --
11 | Repair the short to voltage in the circuit YE between the brake light switch, splice S301, the brake lights, the center high-mounted stop lamp, and the ABS wiring harness connector at the electronic brake control module (EBCM) terminal 41. Did you complete the repair? | -- | Go to Step 17 | --
12 |

1. Disconnect the EBCM connector.
2. Measure voltage between pins 16 and 41 of the EBCM harness connector.
3. Have an assistant step on the brake pedal.

Does the voltage measure within the specified range?

11-14 V

Go to Step 14

Go to Step 13

13 |

1. Examine the connection between the connector and the EBCM terminals 16 and 41.
2. Examine the connection at terminal 1 of connector C110.
3. Examine the wiring of circuit L-BU between splice S301 and terminal 41 of the EBCM connector for an open condition.
4. Examine the wiring between ground G106 and terminal 16 of the EBCM connector.
5. Repair the broken wire or the defective connector terminal, or replace the connector, the wiring harness as required.

Did you complete the repair?

--

Go to Step 17

--

14 | Inspect the interface between the EBCM connector and the EBCM. Is there damage at the interface? | -- | Go to Step 15 | Go to Step 16
15 | Repair the connector or replace the wiring harness or the EBCM as required. Did you complete the repair? | -- | Go to Step 17 | --
16 | Replace the EBCM. Did you complete the replacement? | -- | Go to Step 17 | --
17 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK