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P0504 Brake pedal position A/B correaltion

AutoHex Online Help: Hyundai H-1(A1) 2009
Component Location
General Description

Brake switch is connected to brake pedal and transmits brake operating state to ECM. When the output signal of APS is higher than what driver intended during driving (e.g. short to high voltage line in APS circuit, false signal ), driver depresses brake pedal. Like this, if driver’s decelerating intension is transmitted to ECM (break pedal depressed)when APS output voltage is high, ECM recognizes APS trouble and Limp Home mode is activated. At Limp Home mode, engine speed is fixed at approx. 1000RPM and engine power generation is limitted. Even at Limp home mode, if correct APS signal is detected, Limp Home mode is deactivated. Brake switch, which monitors proper operation of APS, is devided 1 and 2 for the fidelity of brake switch.



DTC Description

When brake switch operates correctly, switch 1 is OFF and switch 2 is ON when releasing brake pedal, while switch 1 is ON and switch 2 is OFF when depressing brake pedal. thus when the signal from a switch is different from the other’s, brake switch is in good condition. When the signal from a switch is same as the other’s, brake switch is fault.

DTC Detecting Condition

Item

Detecting Condition

Possible Cause

DTC Strategy

? Signal monitoring(Brake signals not plausible)

? Brake switch component

? Abnormal brake pedal height

? Brake switch circuit

Enable Conditions

? IG KEY "ON"

Threshold Value

? Wiring open

Diagnostic Time

? 90 sec.

Fail Safe

Fuel Cut

NO

EGR Off

NO

Fuel Limit

NO

Check Lamp

NO

Specification

Condition

Brake Pedal Released

Brake Pedal Depressed

Switch State

Switch 1

Switch 2

Switch 1

Switch 2

Opened

Closed

Closed

Opened

Schematic Diagram
Signal Waveform