Spicer TPCS Troubleshooting Guide User Manual

Page 31

Service Codes

Group: 12C! (Codes 51,

52
, 53
, 54
, 55
, 56
)

PCU Solenoids (Codes 51, 52, 53, 54, 55, 56)

Replace ECU.

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.

Switch off ignition.
Disconnect harness at
PCU 10-way connector.

Are all

resistance

measurements

7-25 ohms?

Check for shorts between PCU connector

pins B, C, D, G, E, K and vehicle ground.

(Do not use multi-meter’s continuity “beep
mode,” as most meters will falsely identify

the 7-25 ohm coils as shorted.)

Are any pins

shorted to

ground?

Repair or replace

connections,

coils or PCU.

Disconnect ECU harness
connectors.
Check continuity of harness pins
shown in chart for given fault
code: PCU harness connector to
ECU harness connector.

Are circuits

continuous?

Repair or replace

harness.

Are

connections

OK?

Code 12C! Indicates one or more solenoid faults. Use service tool to determine the
specific solenoid. When the troubleshooting instructions refer to connector test
points, use chart select the pin test point for use with the particular fault code you
are diagnosing.

Measure at PCU harness connector.

Verify continuity between:

- A and F
- A and H.

Verify no continuity between any combination
of pins B, C, D, E, G, K on PCU harness
connector and K2 on ECU harness connector.
(Do not use multi-meter’s continuity “beep
mode,” as most meters will falsely identify the
7-25 ohm coils as shorted.)

Measure solenoid coil resistance on PCU 10-way connector.

Front (51): F – G Supply (54): H – C
Rear (52): F – E Deflate (55): H – B
Trailer (53): A – K Control (56): F – D

Repair or replace

connections, coils or PCU.

Solenoid/

Code

Any

Code

Any

Code

Front

(51)

Rear

(52)

Supply

(54)

Deflate

(55)

Control

(56)

PCU Harness

Connector

ECU Harness

Connector

Trailer

(53)

Repair or replace

harness.

Yes