3.
Has a problem been found?
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Go to "Power Circuit Inspection" procedure.
The brake switch has 2 contacts. One allows the stop lights to be supplied and the other is used for finding fault and the correlation between the accelerator pedal position and the brake pedal position.
Also, the brake switch has the cancellation of cruise control.
The ECM senses the state of brake operating through brake switch. The redundant brake circuit is actuated when the accel pedal is depressed and the brake pedal depressed.
The ECM will apply a fail safe mode limiting the signal from the accelerator and controlling the injector operation allowing the engine to 1200 rpm only when the brake is released, APS signal is returned and injector operation re-instated.
If the brake switch 1 and 2 signal is not geneated normally, the ECM judged this as a fault and DTC is set.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Signal check | ● Open in brake switch 1 & 2 circuit ● Short in brake switch 1 & 2 circuit ● Open or short in power circuit ● Fuse blown ● Faulty brake switch ● Faulty ECM |
Enable Conditions | ● Ignition on | |
Threshold Value | ● Case 1: brake switch 1 signal and brake switch 2 signal are abnormally correlated after the ignition switch on. ● Case 2: brake switch 1 signal and brake switch 2 signal are abnormally correlated during the driving | |
Diagnostic Time | ● Case 1: 2 sec ● Case 2: 180 sec | |
MIL Fuel Limit Fuel Cut EGR Off | ● No ● No ● No ● No | |
Fail safe | ● Clutch error monitoring deactivited ● Cruise control system and error monitoring deactivited ● Idle compensation deactivited in case of the lack of battery voltage |
Connect scantool to Data Link Cable (DLC).
Monitor "Brake Switch" parameter on the scantool .
Fig 1) Normal value when depressing brake pedal.
Is the Current data displayed correctly ?
▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
▶ Go to "W/Harness Inspection" procedure.
Many malfunctions in the electrical system are caused by poor harness and terminals.
Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Go to "Power Circuit Inspection" procedure.
Check for open or short in Power harness
Ignition "OFF" & Engine "OFF".
Disconnect Brake switch connector.
Ignition "ON" & Engine "OFF".
Measure voltage between terminal 2 of the Brake switch harness connector and chassis ground.
Measure voltage between terminal 3 of the Brake switch harness connector and chassis ground.
Specification : B+
Is the measured voltage within specifications ?
▶ Go to "Ground Circuit Inspection" procedure.
▶ Check for open or short in the power harness.
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Check for short to battery in Brake SW 1 and 2 signal harness.
Ignition "OFF" & Engine "OFF".
Disconnect Brake switch sensor connector.
Ignition "ON" & Engine "OFF"
Measure voltage between terminal 1 of Brake switch harness connector and chassis ground
Measure voltage between terminal 4 of Brake switch harness connector and chassis ground
Specification : Approx. below 1V
Is the measured voltage within specifications ?
▶ Go to "Check for short to ground in harness" as below.
▶ Check for short to battery in harness.
Repair as necessary and go to "Verification of Vehicle Repair" procedure
Check for short to ground in harness.
Ignition "OFF" & Engine "OFF".
Disconnect Brake switch and ECM connector.
Measure resistance between terminal 4 of Brake switch harness connector and chassis ground.
Measure resistance between terminal 1 of Brake switch harness connector and chassis ground.
Specification : Infinite
Is the measured resistance within specifications ?
▶ Go to "Check for open in harness" as below.
▶ Check for short to ground in harness.
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Check for open in harness
Ignition "OFF" & Engine "OFF".
Disconnect Brake switch and ECM connector.
Measure resistance between terminal 4 of Brake switch harness connector and terminal 54 of ECM harness connector.
Measure resistance between terminal 1 of Brake switch harness connector and terminal 59 of ECM harness connector.
Specification : Approx. below 1Ω
Is the measured resistance within specifications ?
▶ Go to "Component Inspection" procedure.
▶ Check for open in harness.
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
Check Brake Switch
Ignition "OFF".
Disconnect Brake Switch connector.
Check continuity between terminal 1 and 2 of Brake switch connector (Component side).
Check continuity between terminal 3 and 4 of Brake switch connector (Component side).
Brake Pedal OFF | Brake Pedal ON | ||
Switch 1 | Switch 2 | Switch 1 | Switch 2 |
No continuity | Continuity | Continuity | No continuity |
Is the measured continuity status within specifications ?
▶ Substitute with a known-good ECM and check for proper operation.
If the problem is corrected, replace ECM and then go to "Verification of Vehicle Repair" procedure.
▶ Check Brake switch for contamination, deterioration, or damage. Substitute with a known-good Brake switch and check for proper operation. If the problem is corrected, replace Brake switch and then go to "Verification of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode and then clear DTC.
Operate the vehicle within DTC Enable conditions in General information.
Are any DTCs present ?
Go to the applicable troubleshooting procedure.
System is performing to specification at this time.
