Circuit Description
The Stoplamp Switch is a normally open switch. When the brake pedal is depressed the EBCM senses battery voltage. This allows the EBCM to determine the state of the brake lamps. An open brake switch circuit will result in a modified ABS entrance criteria and possibly false settings of excessive wheel speed variation codes (C1225 thru C1228).
Conditions for Running the DTC
This DTC can set anytime that the EBCM is powered.
Conditions for Setting the DTC
The brake switch input voltage is between 1.87 volts and 5.28 volts for 2.0 seconds.
Action Taken When the DTC Sets
| • | A malfunction DTC is stored |
| • | ABS and ETS remains functional. |
Conditions for Clearing the DTC
| • | The condition for setting the DTC is no longer present and the scan tool Clear DTCs function is used. |
| • | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
| • | The following are possible causes of this DTC: |
| - | The signal circuit of the brake switch is open. |
| - | The brake switch is misadjusted. |
| - | All of the brake lamps are open. |
| - | All of the brake lamp grounds are open. |
| - | The circuit has a wiring problem, terminal corrosion, or poor connections. |
| - | Loose or corroded EBCM ground. |
| - | An internal EBCM malfunction. |
| • | It is very important that a thorough inspection of the wiring and the connectors be performed. Failure to carefully and fully inspect the wiring and the connectors may result in a misdiagnosis, causing part replacement with a reappearance of the malfunction. |
| • | If an intermittent malfunction exists refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |
2 | Press the brake pedal. Do the brake lamps turn ON? | -- | Go to Step 3 | Go to Diagnostic System Check - Lighting Systems in Lighting Systems |
3 |
Does the scan tool display that the Brake Switch Status is ON? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 |
Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 5 | |
5 | Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 6 |
6 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 7 | -- |
7 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
