Service Brake Pedal Position (Switch 1) Circuit

373

TM 9-2320-312-24-2

Troubleshooting Section

Cruise Control On/Off Switch

B. Remove P1:66 remote accelerator position

sensor from the ECM connector P1.

PTO On/Off Switch

C. Remove terminal "C" (Accelerator Pedal Position)

Cruise Control Pause Switch

from the connector for the remote accelerator

position sensor.

The switches are described in the respective circuit

D. Route new wiring from the ECM to the remote

tests in Troubleshooting.

accelerator position sensor.

All of the following Customer Programmable

E. Turn the ignition key switch to the ON position.

Parameters can affect cruise control, idle set speed,

fast idle, and PTO operation:

F. Check the duty cycle of the remote accelerator

"Low Cruise Control Speed Set Limit"

position sensor with ET while the accelerator

pedal assembly is being moved over the full

"High Cruise Control Speed Set Limit"

range.

"Idle Vehicle Speed Limit"

Expected Result:

"Fast Idle RPM #1"

The duty cycle is between 10 and 22 percent with

the accelerator pedal assembly in the low idle

"Fast Idle RPM #2"

position, and the duty cycle is between 75 and 90

percent with the accelerator pedal assembly in the

"Cruise/Idle/PTO Switch Configuration"

high idle position.

"Idle/PTO Bump rpm"

Results:

OK The wiring from the ECM to the accelerator

"Idle/PTO rpm Ramp Rate"

position sensor appears faulty. Permanently install

"PTO Vehicle Speed Limit"

new wiring. Verify that the repair eliminates the

problem. STOP.

"Cruise Pause Switch"

Not OK Double check the wiring, the ECM

The vehicle speed calibration can also affect the

vehicle harness connector J1/P1 and the sensor

cruise control, fast idle, the idle set speed, and the

connector. If a problem still exists, restart the test

PTO if the vehicle speed calibration is incorrectly

procedure. STOP.

programmed. Refer to Troubleshooting, "Customer

Specified Parameters".

i01858070

Service Brake Pedal Position

Service Brake Pedal Position (Switch 1)

(Switch 1) Circuit - Test

The switch for the Service Brake Pedal Position

(Switch 1) is normally closed when the respective

SMCS Code: 1900-081-ZS

pedal is released. Depressing the brake pedal

should open the individual circuit. This switch is

System Operation Description:

OEM supplied. The Service Brake Pedal Position

(Switch 1) is typically a pressure switch.

Use this procedure under the following situation:

This switch may not be connected to an input on the

Use this procedure to determine if the Service

ECM. The parameter "Service Brake Pedal Position

Brake Pedal Position (Switch 1) is preventing normal

Switch # 1" determines the input to the ECM. If the

operation of cruise control, fast idle, idle set speed,

parameter is programmed to J1/P1:45 a switch

or PTO operation:

must be connected to terminal 45. If the parameter

is programmed to one of the J1939 options, the

The following switch circuits can also prevent the

switch position will be transmitted to the ECM over

correct operation of the cruise control, fast idle, idle

the J1939 data link. If a problem is suspected

set speed or PTO operation:

with the J1939 data link, refer to Troubleshooting,

"Powertrain Data Link Circuit - Test".

Service Brake Pedal Position (Switch 2)

The following background information is related

Neutral switch

to this procedure:

Cruise Control Set/Resume Switch