PIT5058E

Bulletin No.: PIT5058E
Published date: 12/13/2018
Preliminary Information
PIT5058E Diagnostic Tip - School Bus Brake Warning System RPO
UJ1 Functional Test and Diagnostics
Models
Brand:
Model:
Model Years:
VIN:
from
to
Engine:
Transmissions:
Chevrolet
Express Cutaway or Cargo Chassis
2008 - 2019
All
All
All
All
GMC
Savana Cutaway or Cargo Chassis
2008 - 2019
All
All
All
All
With RPO UJ1
Supersession Statement:
This PI was superseded to add Model Years. Please discard PIT5058D.
Condition / Concern
Some dealers may need information on the operation and diagnostics of the UJ1 brake
warning pressure warning system.
Recommendations / Instructions
To test for the proper function and operation of the UJ1 brake warning system:
1. Turn key to on position (Do not start engine) Park brake not applied.
2. Wait approximately 2 seconds.
3. Brake symbol will come on and chime will sound.
4. Start engine, light should go out and chime should stop.
If the warning system does not function correctly, then follow the below diagnostics:
1. Disconnect X141 (left rear of the engine compartment near the cowl) and the brake light and chime should be
o . If the light and chime are still on then check circuit 33 for a short to ground between X141 and the IPC
terminal 14.
2. Ground terminal A on the female side with the engine on and park brake released and the brake light and
chime should come on. If the light and chime does not come on then check circuit 33 for an open between X141
and the IPC terminal 14.
3. Check male side of X141 circuit 33 with an ohm meter to ground and should be close to 0 ohms with engine o
and key on. Start engine and circuit should go OL indicating that the ow switch opened. Then, turn the steering
to the stop in pressure relief (do not hold for more than 5 seconds)
and verify that the circuit stays OL to check the operation of the pressure switch.
Warranty Information
The correction for this concern may be one of several repairs described in the diagnostic tips
above. For vehicles repaired under warranty, please use the appropriate warranty labor
operation based on the actual cause and repair.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is
resolved without completing every step, the remaining steps do not need to be performed.
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