DTC Troubleshooting: P0504 (159-1)

DTC P0504:  Brake Pedal Position Switch Circuit Malfunction

1.Turn the ignition switch ON (II).

2.Check BRAKE PEDAL POSITION SWITCH B in the DATA LIST with the HDS when the brake pedal pressed.

Is ON indicated?


YES - Go to 3.


NO - Check the brake pedal position switch, then go to 29.


3.Check BRAKE PEDAL POSITION SWITCH A in the DATA LIST with the HDS when the brake pedal pressed.

Is ON indicated?


YES - Go to 4.


NO - Go to 7.


4.Release the brake pedal.

5.Check BRAKE PEDAL POSITION SWITCH B in the DATA LIST with the HDS.

Is OFF indicated?


YES - Go to 6.


NO - Go to 20.


6.Check BRAKE PEDAL POSITION SWITCH A in the DATA LIST with the HDS.

Is OFF indicated?


YES - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the brake pedal position switch and the ECM.n


NO - Check the brake pedal position switch, then go to 29.

7.Check the brake lights.

Do the brake lights come on?


YES - Go to 8.


NO - Go to 12.


8.Turn the ignition switch OFF, and wait 30 seconds.

9.Disconnect the brake pedal position switch 4P connector.

10.Disconnect ECM connector No. 2 (58P).

11.Check for continuity between ECM connector No. 2 terminal No. 38 and brake pedal position switch 4P connector terminal No. 1.

 

Is there continuity?


YES - Go to 34.


NO - Repair open in the wire between the brake pedal position switch and ECM connector No. 2 terminal No. 38, then go to 30.

12.Turn the ignition switch OFF.

13.Disconnect the brake pedal position switch 4P connector.

14.Measure voltage between brake pedal position switch 4P connector terminal No. 2 and body ground.

 

Is there battery voltage?


YES - Go to 16.


NO - Go to 15.


15.Check the No. 14 HORN & STOP (15 A) fuse in the under-hood fuse/relay box.

Is the fuse OK?


YES - Repair open in the wire between the brake pedal position switch and the No. 14 HORN & STOP (15 A) fuse, then go to 30.


NO - Repair short in the wire between the brake pedal position switch and the No. 14 HORN & STOP (15 A) fuse. Also replace the No. 14 HORN & STOP (15 A) fuse, then go to 30.

16.Turn the ignition switch OFF, and wait 30 seconds.

17.Disconnect ECM connector No. 2 (58P).

18.Check for continuity between ECM connector No. 2 terminal No. 38 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the brake pedal position switch and ECM connector No. 2 terminal No. 38, then go to 30.


NO - Go to 19.


19.Check the brake pedal position switch.

Is the brake pedal position switch OK?


YES - Go to 34.


NO - Adjust or replace the brake pedal position switch, then go to 30.

20.Turn the ignition switch OFF, and wait 30 seconds.

21.Disconnect ECM connector No. 2 (58P).

22.Disconnect the brake pedal position switch 4P connector.

23.Disconnect the cruise control switch 13P connector.

24.Check for continuity between ECM connector No. 2 terminal No. 26 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the brake pedal position switch, the cruise control switch and ECM connector No. 2 terminal No. 26, then go to 30.


NO - Go to 25.

25.Check for continuity between ECM connector No. 2 terminal No. 26 and brake pedal position switch 4P connector terminal No. 4.

 

Is there continuity?


YES - Go to 26.


NO - Repair open in the wire between the brake pedal position switch and ECM connector No. 2 terminal No. 26, then go to 30.

26.Check for continuity between ECM connector No. 2 terminal No. 36 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the brake pedal position switch and ECM connector No. 2 terminal No. 36, then go to 30.


NO - Go to 27.

27.Check for continuity between ECM connector No. 2 terminal No. 36 and brake pedal position switch 4P connector terminal No. 3.

 

Is there continuity?


YES - Go to 28.


NO - Repair open in the wire between the brake pedal position switch and ECM connector No. 2 terminal No. 36, then go to 30.


28.Check the brake pedal position switch.

Is the brake pedal position switch OK?


YES - Go to 34.


NO - Adjust or replace the brake pedal position switch, then go to 30.

29.Turn the ignition switch OFF.

30.Reconnect all connectors.

31.Turn the ignition switch ON (II).

32.Reset the ECM with the HDS.

33.Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC P0504 is indicated, check for poor connections or loose terminals at the brake pedal position switch, the cruise control switch and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


NO - Troubleshooting is complete.n


34.Update the ECM if it does not have the latest software, or substitute a known-good ECM.

35.Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC P0504 is indicated, check for poor connections or loose terminals at the brake pedal position switch, the cruise control switch and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


NO - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM.n