ReAX Module
Replacement Procedure
Electrical Steering Assist System
Steering

Table of contents
I

Symbols used in this document .......................................................................................... 4

II

Information on the document .............................................................................................. 5

III

Safety information ............................................................................................................... 7

IV

List of abbreviations ............................................................................................................ 8

V

Scope of this document ...................................................................................................... 9

1

ReAX module replacement ................................................................................................ 10

2

Tools .................................................................................................................................. 11

3

First Steps........................................................................................................................... 12

4

Removal and installation procedure................................................................................... 16

5

Appendix ........................................................................................................................... 32

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Infringements lead to civil and criminal prosecution.
The English version is the original document.

ReAX module replacement procedure

3

Symbols used in this document
I

Information on the document

Symbols used in this document

II

Information on the document

Document overview

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WARNING

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Purpose of this document

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Reference to information on the internet

Descriptive text
–

Action step

Action step 1 (in ascending order)
Action step 2 (in ascending order)
Ö Consequence of an action
•

4

Listing

ReAX module replacement procedure

ReAX module replacement procedure

5

Information on the document

Safety information
III

Additional services
The package you will get with a genuine ZF part:
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Read this publication carefully.
Adhere to all instructions, information and safety information to prevent injury to persons and damage
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Phone: 1-800-879-0899
Email: css.trucksteering@trw.com
Online product catalogue
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Safety information

https://www.trwaftermarket.com/us/products/heavy-duty/service-literature/

Make provisions for a safe work environment:
•
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6

ReAX module replacement procedure

ReAX module replacement procedure

7

List of abbreviations
IV

Scope of this document

List of abbreviations

V

Scope of this document

Abbrev.

Meaning

This section provides a brief overview of the structure of this document:

CAN

Controller Area Network; asynchronous serial bus system for networking control units in vehicles

Chapter 1 - ReAX module replacement
Description of the ReAX unit, and how to remove the current unit and replace it with a new unit.
Chapter 2 - Tools
In this chapter you can find a list of tools required to complete the replacement procedure.
Chapter 3 - First Steps
Description of preparation steps before beginngin removal procedure..
Chapter 4 - Removal and installation procedure
Description of removal of the ReAX unit and installation of a new ReAX unit.
Chapter 5 - Appendix
Information on ZF Contacts and sample forms..

8

ReAX module replacement procedure

ReAX module replacement procedure

9

ReAX module replacement
1

Tools

ReAX module replacement

2

ReAX Module is an Electrical Steering Assist Motor that provides additional steering assistance based on
the torque input from the steering wheel shaft by the Driver. This procedure will explain the process step
by step to remove the ReAX module from the Column and replace it with a new ReAX module as part of
the field repair work. Below is the picture of the ReAX Column with components marked up for reference.

Tools

This chapter provides an overview of the tools necessary to complete the replacement of the ReAX
module.
Tools
13 mm hex socket
9/16˝ hex socket
1/2˝ hex socket
1 ¼˝ hex socket
5/16˝ x 24 fine thread tap for steering wheel holes
HF 2 ft breaker bar with 1/2˝ drive
Short, long, & flexible bit extenders with PH2 bits
Ratchet with long & short extensions
Cordless impact driver & drill
6 mm allen wrench
Torque wrench (capable of at least 50 ft-lb torque reading)
Steering wheel puller kit with bolts
Wire cutter/strippers 18-20Ga
Crimpers & extra 18-gauge wire
Electrical ring connectors 18-20 Ga
Electrical butt connectors 18-20 Ga
Work light, flashlight
Paint marker
ZF Testman DPA06 & associated harnesses
Laptop with ZF Testman

CAN Connector

Sensor Connector
4020580a

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ReAX module replacement procedure

ReAX module replacement procedure

11

First Steps
3

First Steps

First Steps

Before beginning ReAX Module replacement, ensure all required connections are complete and correctly
installed.
Verifying with ZF Testman
The ZF Testman Diagnostic tool can be used to verify column function as a first check. Connect the ZF
Testman tool to the J1939 diagnostic port and connect to the column. (Follow step 43 below for Testman
connection procedure). If connection to the column is established, then column power and column CAN
connection is correct. If connection via Testman is not established, ensure that column Power and CAN
connection are present by following the steps below

If column power harness does not provide 12V after verifying installation of 60A fuse, contact tech support
for assistance.
CAN Connection
ZF ReAX Column electric torque overlay requires specific CAN signals from the vehicle CAN bus to
function correctly. Some buses have had the CAN harness disconnected at the column and others have
disconnected the CAN harness at a 3-way Deutsch connector located under the turn signal plate.
The turn signal plate is located to the left of the steering column on the floor and features button-style
switches for operating the turn signals. The 3-way connector can often be found under the forward edge
of the plate. Verify that the male 3-pin plug is connected to the 3-way connector.

Column Power
Ensure the column power harness is correctly installed and providing 12V of power while ignition is turned
on. (An audible click can be heard from the ReAX Module once column receives 12V of power.)
Each column power harness features a 60A fuse that is located behind the side panel to the driver’s left.
Verify that the fuse is correctly installed and functioning properly.
.

The CAN harness also carries an ignition signal through pin 5 that is critical for ReAX to function. Verify
that PIN 5 in on the CAN connector provides 12V when ignition is turned on.

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ReAX module replacement procedure

ReAX module replacement procedure

13

First Steps

First Steps
Traceability Information Capturing
Document the following in the excel spreadsheet – “Return Form – ReAX Field Work”:
• Date of Repair
• VIN# (Located above the driver’s seat, to the left)
• Bus# (Usually can be seen in center of windshield)
• Mileage
• New ReAX Module S/N (15-digit alpha numeric code, printed twice)

After verifying the CAN harnesses is properly connected to the vehicle, be sure that the CAN harness is
correctly connected to ReAX column.

Verifying Vehicle Wheels are Straight Ahead
Visual inspection of the direction of the road wheels is typically insufficient for the column centering
process. It is preferred that the vehicle is driven forward, straight ahead to verify that the road wheels are
perfectly positioned straight ahead.
After following the recentering procedure (starting at step 47 below), it may be necessary for a test drive
to verify that the column has been centered correctly. Incorrect centering process may lead to the steering
column applying torque to the steering wheel while driving straight ahead.

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ReAX module replacement procedure

ReAX module replacement procedure

15

Removal and installation procedure
4

Removal and installation procedure

Removal and installation procedure

5. Telescope column almost all the way down - pull tilt/tele handle up and push steering wheel straight
down to lowest position, then pull back up about ¾” (just enough to access ReAX module attachment
bolts & nuts).

WARNING
To prevent serious eye injury, always wear safe eye protection when you perform vehicle maintenance or service.

WARNING
Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving. Support the vehicle with
safety stands. Do not work under a vehicle supported only by jacks. Jacks can slip and fall over. Serious personal
injury and damage to components can result.

WARNING
When you work on an electrical system, the possibility of electrical shock exists, and sparks can ignite flammable
substances. You must always disconnect the battery ground cable before you work on an electrical system to
prevent serious personal injury and damage to components.

1. Set the front wheels of the bus straight to facilitate ReAX module installation.
Make sure the bus ignition is Off and does not turn On during the procedure until instructed to
do so. This is CRITICAL.
2. Cover driver’s seat with clean work towel to protect seat from stains.

6. Under the dash, cut horn power wire with plenty of extra length (~ 12” from dash) and remove #2
Phillips screw securing horn ground wire to column. You may have to cut wire ties under dash to get