Park brake switch faulty or stuck in the closed (applied) position; Wiring short to ground on the switch signal circuit, for example from chafing near the handbrake lever or underbody; Corroded, damaged or contaminated switch connector causing a low signal; Parking brake lever or cable mis-adjusted so the switch is held closed even when released; Faulty parking brake actuator or position sensor (on vehicles with an electronic parking brake); Fault inside the control unit that reads the switch signal; Outdated or faulty control unit software, only where the manufacturer has documented it as a cause.

P05E4

Park Brake Sensor/Switch Circuit Low.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
5: AreaVehicle speed, idle control and auxiliary inputs
E4: FaultThe specific fault in that area

What it means

P05E4 means the control unit has seen the park brake sensor or switch circuit signal sitting lower than its expected voltage range. This usually points to a short to ground, a switch stuck in the 'applied' position, or a fault in the sensor or its wiring. The exact circuit layout and which module sets the code depend on the vehicle and whether it has a lever or electronic parking brake.

Symptoms

Brake warning light or parking brake warning light on the dash, possibly staying on with the brake released
Other warning lights or messages about the parking brake or brake system
Hill-hold, auto-hold or automatic parking brake functions not working (if fitted)
Stop-start system disabled or behaving oddly (on some models)
Electronic parking brake not applying or releasing properly (if fitted)
Engine management warning light on with the code stored

Possible causes

Park brake switch faulty or stuck in the closed (applied) positionlikely
Wiring short to ground on the switch signal circuit, for example from chafing near the handbrake lever or underbodylikely
Corroded, damaged or contaminated switch connector causing a low signallikely
Parking brake lever or cable mis-adjusted so the switch is held closed even when releasedpossible
Faulty parking brake actuator or position sensor (on vehicles with an electronic parking brake)possible
Fault inside the control unit that reads the switch signalrare
Outdated or faulty control unit software, only where the manufacturer has documented it as a causerare

How to diagnose

Read all stored codes and freeze frame data, and note whether other brake, ABS or body control codes are present.
Check the parking brake is fully released and that the lever or pedal returns fully, and look at the dash warning light behaviour.
Inspect the switch, its connector and the surrounding wiring for damage, water ingress, corrosion, chafing or signs of previous repair.
Using a scan tool, watch the live parking brake switch status while applying and releasing the brake, and check it changes state correctly.
Check cable adjustment and lever travel against the manufacturer's specification, as this depends on the model.
With the connector unplugged, check the signal wire for a short to ground and check the supply and ground against the wiring diagram.
Test the switch itself for correct resistance or continuity in both positions.
On electronic parking brake systems, follow the manufacturer's procedure for checking the actuator and sensor, as it varies by model.

How to fix

Replace the park brake switch if it is stuck or reads incorrectly in either position.
Repair or replace shorted, chafed or damaged wiring and secure it clear of moving or hot parts.
Clean, repair or replace corroded or damaged connectors and terminals.
Adjust or repair the parking brake lever and cable so the switch is released correctly.
Repair or replace the electronic parking brake actuator or sensor if testing shows it is faulty.
Update the control unit software only if the manufacturer lists it as a fix for this fault, then clear the code and confirm it does not return.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but get it checked soon because the parking brake may not hold or release properly. If the car has an electronic parking brake, or the brake warning light is on with any change in braking feel, limit driving until it is checked.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.