Spicer CTIS (Central Tire Inflation System) Troubleshooting Guide User Manual

Page 37

Service Codes

Pressure Switch (Code 31)

Is the pressure

switch plugged in?

Plug in pressure switch

and retest system.

Using the diagnostic tool, verify

pressure switch operation.

Does the

pressure switch open

below psi value shown

in table?

Verify correct vehicle configuration.

See Configuration Error flowchart.

Service code is not active. Reverify

flowchart steps and wait for fault to reoccur.

Is there

continuity?

Repair harness and retest.

Replace pressure

switch and retest

system.

Yes

Using the diagnostic tool,

verify pressure switch

status is closed.

Switch off ignition.
Disconnect the ECU connector
and the pressure switch connector.
Verify NO continuity between:

ECU Harness Connector Pins
T and F (round connector)
or
G3 and K2 (rectangular connector)

Part Number

673345 (black)

676770 (blue)

Pressure Switch

Open Value

78 psi

87 psi

Identify vehicle pressure switch:

Part #673345 (black)
Part #676770 (blue)

Use diagnostic tool to
read supply pressure.

Is supply pressure

accurate?

Yes

Replace PCU and recheck system.

Note: While replacing the PCU, pay

particular attention to possible air line

contamination (e.g., oil, water,

particles) which may suggest further

air system maintenance needs.

Does fault

reoccur?

Complete

Replace ECU and recheck system.

Note: ECUs are not a typical cause

of problems. If an ECU is replaced,

the system should be carefully

rechecked to make sure the problem

has been fixed and does not reoccur.

Yes