Spicer TPCS Troubleshooting Guide - Manual (Page 43)

40
Service Codes
Group: 7P! (Codes 31, 32)
Low Air Supply (Codes 31, 32)
Is the governor
cutout pressure set
at 120-125 psig?
Reset governor cutout
pressure and retest system.
Refer to Service Manual
Is the pressure
switch plugged in?
Plug in pressure switch
and retest system.
Refer to Service Manual
Using the diagnostic tool, verify
pressure switch operation.
Does the
pressure switch
close above 110
psi?
Verify wiring:
Switch off ignition.
Disconnect ECU harness connector and
supply tank pressure switch connector.
Verify continuity between ECU harness
connector pin G3 and pressure switch
harness connector PRESS SW wire.
Verify other press switch wire is grounded.
Are
connections
OK?
Repair
harness and
retest.
Verify air system capacity by checking
supply tank pressure buildup time.
Does the
supply tank build
up pressure?
Service code is not active. Reverify
flowchart steps and wait for fault to reoccur.
Replace pressure switch
and retest system.
Refer to Service Manual
No
No
Yes
Yes
No
Yes
Yes
No
Use diagnostic tool to determine type of fault.
Pressure
switch failed. Open or
closed?
Is there a
short?
Repair harness
and retest.
Replace pressure
switch and retest.
Verify wiring:
Switch off ignition.
Disconnect ECU harness connector and
supply tank pressure switch connector.
Check for shorts between ECU harness
connector pins G3 and K2.
Repair vehicle air supply
system and retest.
Refer to Service Manual
No
Yes
Closed
No
Yes
Open