C0161

DTC C0161





Step 1-4





Step 5-15

Circuit Description
The Stoplamp Switch is a normally open switch, when the brake pedal is depressed the EBCM will sense battery voltage. This allows the EBCM to determine the state of the brake lamps.

Conditions for Running the DTC
- The ignition switch is ON.
- The DTC can be set after system initialization.

Conditions for Setting the DTC
- EBCM detects battery voltage at all times.
- EBCM never detects battery voltage from CKT 17.
- Both brake lamps are faulty.

Action Taken When the DTC Sets
If equipped, the following actions occur:
- The EBCM disables the ABS/TCS for the duration of the ignition cycle.
- A malfunction DTC will set.
- The ANTI-LOCK indicator turns ON.
- The TRAC Off indicator turns ON.
- The Red BRAKE Warning indicator could turn on.

Conditions for Clearing the DTC
- The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
- The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids
- It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
- Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- Poor terminal-to-wiring connections
- Physical damage to the wiring harness
- The following conditions may cause an intermittent malfunction:
- A poor connection
- Rubbed-through wire insulation
- A broken wire inside the insulation
- If an intermittent malfunction exists refer to Testing for Intermittent and Poor Connections.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. This DTC detects an open stoplamp switch signal circuit from the stoplamp side of the splice to the EBCM.
4. The EBCM sources 5 volts on the stoplamp switch signal circuit. This small voltage has a ground path through the stoplamp bulbs. This DTC sets if the path to ground is open.
7. With the scan tool, Test for the current state of the brake lamp switch parameter.
10. Test the stoplamp signal circuit for a short to voltage.