C1157
Park Brake Actuator Assembly Switch Applied Circuit Failure
Chassis Chassis/Safety Park Brake Control 🔴 Serious — Stop or limit driving
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What This Actually Means
In plain language — no jargon

The parking brake actuator switch isn't communicating properly with the engine control unit, similar to a light switch that's broken or loose and won't signal when it's pressed. The vehicle's computer can't confirm the parking brake is engaged or released.

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Symptoms You May Notice
3 known symptoms for this code
Parking brake warning light stays on or flickers
Parking brake does not engage or disengage smoothly
Reduced braking performance or ABS warnings
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors the voltage signal from the park brake actuator switch to verify engagement status. It expects a clean digital transition when the brake is applied or released. If the signal is intermittent, stuck, or out of range, a circuit failure is logged.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Switch Signal Voltage 0V (released) or 12V (applied) Floating, stuck, or erratic voltage outside expected logic
Signal Continuity Stable state with clear transitions Intermittent dropout or no response to actuator command
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Electrical connector at park brake actuator
Inspect and reseat the connector; clean corrosion with contact cleaner.
2
Wiring harness to park brake switch
Check for pinched, frayed, or damaged wires along the harness route.
3
Park brake actuator assembly
Replace the entire actuator unit if connector and wiring are confirmed good.