Fault Code Guide

Fire Pump Control Interlocks by Reference Parameter
Reference
Parameter
Description
Interlocks
Indicated Vehicle Speed from
Engine
*
Ignition (BHM
input)
Park Brake
(from CHM)
26-01032-004
PTO Fire Pump Control (Smart
Switch ID#104)
— On Set
26-01032-010
PTO Fire Pump Control, w/Park
Brake & Veh Spd Interlocks (Smart
Switch ID#104)
Approximately 5 mph (8 km/h) On Set
*
The fire pump is driven by a transfer case. When the transfer case is shifted to deliver power to the fire pump, the transmission is put into gear to drive the
transfer case (the vehicle will be stationary). Since the transmission drives the transfer case, an apparent output shaft speed will register indicating vehicle
speed. In order to engage the fire pump, this apparent output shaft speed must be under 5 mph (8 km/h). Once the transfer case is engaged, it will remain en-
gaged regardless of the apparent output shaft speed as long as the ignition is on, the park brake is set, and the pump smart switch remains on.
Table 5, Fire Pump Control Interlocks by Reference Parameter
PTO and Fire Pump Control J1587 Fault Codes
MID SID FMI Description Action
164 025 07 End of Frame Air (PTO and fire pump
control)–unexpected air pressure
feedback
Solenoid is not activated, but CHM senses that the
pressure switch is in an unexpected state. For
example, a normally closed solenoid is off, but air
pressure is detected.
Check the following:
• Air system
• Pressure feedback circuit including the
ground.
• Solenoid–pressure switch may be stuck.
026 07 End of Frame (PTO and fire pump
control)–no air pressure feedback
Chassis Module engages solenoid, but the pressure
switch does not change status indicating that the so-
lenoid supplied, or exhausted, air downstream.
Check the following:
• Air system
• Pressure feedback circuit including the
ground.
• Solenoid–pressure switch may be stuck.
Table 6, PTO and Fire Pump Control J1587 Fault Codes
PTO and Pump Electrical Controls 54.38
Troubleshooting
Business Class M2 Workshop Manual, Supplement 22, September 2012300/8