Jaguar X-Type Sedan and Estate (Wagon). Service manual — part 375

Published: 11-May-2011

Automatic Transmission/Transaxle - Vehicles With: 6-Speed Automatic Transaxle -
AWF21 - Transmission Electronic Control SystemVehicles With: 6-Speed Automatic
Transaxle - AWF21

Description and Operation

CONTROL DIAGRAM - AW F21 6 SPEED AUTOMATIC TRANSMISSION 2009MY

• NOTE: A = Hardwired; D = High speed CAN bus; O = LIN bus

Item

Part Number

Description

1

-

Battery

2

-

Battery Junction Box (BJB)

3

-

Central Junction Box (CJB)

4

-

Transmission Control Module (TCM)

5

-

Selector lever

6

-

Selector lever PRND and M/S Light Emitting Diode (LED) displays

7

-

High speed Controller Area Network (CAN) bus to other vehicle systems

8

-

Instrument cluster

9

-

Steering angle sensor

10

-

Anti-lock Brake System (ABS) module

11

-

Engine Control Module (ECM)

TRANSMISSION CONTROL MODULE (TCM)

Item

Part Number

Description

1

-

TCM

2

-

'Neutral 'N' position

3

-

Park 'P' position

4

-

Position sensor/manual shaft

5

-

Electrical connector

The

TCM (transmission control module)

is located on the top of the transmission casing and is connected on the high speed

CAN (controller

area network)

bus to send and receive information to and from other system modules.

The

TCM

outputs signals to operate the transmission solenoid valves to control the hydraulic operation of the transmission.

The

ECM (engine control module)

supplies the engine management data on the high speed

CAN

bus system. The

TCM

requires engine data

to efficiently control the transmission operation, using for example; crankshaft torque, engine speed, accelerator pedal angle, engine
temperature etc.

The

TCM

processes signals from the transmission speed and temperature sensors,

ECM

and other vehicle systems. From the received signal

inputs and pre-programmed data, the module calculates the correct gear, torque converter clutch setting and optimum pressure settings for
gear shift and lock-up clutch control.

The steering angle sensor and the

ABS (anti-lock brake system)

module also supply data to the

TCM

on the high speed

CAN

bus system.

The

TCM

uses data from these systems to suspend gear changes when the vehicle is cornering and/or the

ABS

module is controlling braking

or traction control.

The

TCM

is positioned over the manual shaft which protrudes through an oil seal on the top face of the main casing. The shaft locates in a

rotary position sensor and turns the sensor in the appropriate direction when a selection is made using the selector lever. The rotary
position sensor is a Hall effect sensor which outputs a specified voltage relating to the selected selector lever position.

The selector lever is connected to the automatic transmission and the rotary position sensor in the transmission by a Bowden cable.
Movement of the selector lever moves the position switch via the Bowden cable and the switch position informs the

TCM

of the selected

position; P, R, N or D. The sport and manual +/- 'Jaguar Sequential Shift' switch passes sport or manual selections to the

TCM

on a

LIN

(local interconnect network)

bus. The

TCM

outputs appropriate information on the high speed

CAN

bus which is received by the instrument

cluster to display the gear selection information in the message center.

If the

TCM

or transmission requires replacement, a setting procedure must be performed using a Jaguar approved diagnostic system to allow

the

TCM

to learn the neutral position of the transmission. The

TCM

uses the neutral position as a reference point for each of the gear

positions P, R, N and D.

INSTRUMENT CLUSTER

The instrument cluster is connected to the

TCM

via the

CAN

.

For additional information, refer to:

Instrument Cluster

(413-01 Instrument Cluster, Description and Operation).

Message Center Display

The message center is located in the speedometer. The message center is a

LCD (liquid crystal display)

to relay vehicle status information

to the driver. The message center will display 'SPORT' when sport mode is selected.
For additional information, refer to:

Information and Message Center

(413-08 Information and Message Center, Description and Operation).

CONTROLLER AREA NETWORK (CAN)

The high speed

CAN

broadcast bus network is used to connect the powertrain modules. The

CAN

bus is connected between the following

electronic units:

High Speed CAN Bus

TCM

Instrument cluster
Steering angle sensor
Restraints control module

ECM
ABS

module.

Diagnostic socket.

The

CAN

bus allows a fast exchange of data between modules. The

CAN

bus comprises two wires which are identified as

CAN

high (H) and

CAN

low (L). The two wires are colored green and yellow and are twisted together to minimise electromagnetic interference (noise) produced

by the

CAN

bus messages.

For additional information, refer to:

Communications Network

(418-00 Module Communications Network, Description and Operation).

In the event of

CAN

bus failure, the following symptoms may be observed:

Transmission operates in default mode
Torque converter lock-up clutch control is disabled.

DRIVING MODES

A number of different driving modes are available. Some can be selected by the driver and some are automatically initiated by the

TCM

to

adapt to different driving conditions.

Normal
Sports
Manual 'Jaguar Sequential Shift'
Cooling
Cruise
Limp home
Coast
Fast off recognition
Uphill and Trailer
Downhill
Wide Throttle
Reverse lock-out

Normal

Normal mode is automatically selected by the

TCM

when the ignition is switched on. In this mode all automatic and adaptive modes are

active. Normal mode uses gear shift and lock-up maps which provides the optimum of fuel consumption, emissions and driveability,
depending on the driving style.

If the transmission is operated in sport mode or 'Jaguar Sequential Shift' mode and the selector lever is moved back to the drive 'D'
position, then normal mode operation is resumed.

Sports

Sports mode provides enhanced acceleration and responsiveness by the use of sports shift maps. This mode allows the transmission to
down shift more readily and hold gears for longer at higher engine speeds.

Manual 'Jaguar Sequential Shift'

Manual 'Jaguar Sequential Shift' mode allows the transmission to operate as a semi-automatic transmission. The driver can change up and
down the six forward gears with the freedom of a manual transmission.

Shift maps are provided to protect the engine at high speeds. The

TCM

will automatically change up to a higher gear ratio to prevent engine

overspeed and change down to a lower gear ratio to avoid engine laboring and stalling.

When kick-down is requested the

TCM

shifts down to the lowest available gear. W hen the vehicle is stationary, the driver can select 1st,

2nd or 3rd to start off.

When moving from a standstill, upshifts can be pre-selected by making '+' selections with the selector lever for the number of upshifts
required. The

TCM

then performs the requested number of upshifts when appropriate shift points are reached. For example; when moving off

in 1st gear, if 3 '+' selections are made in quick succession, the

TCM

will automatically upshift through the gears to 4th gear as the vehicle

accelerates, without any further selections being made.

Cooling

Cooling mode is activated when the

TCM

detects excessively high transmission fluid or engine coolant temperatures. When this mode is

active torque converter lock-up is activated earlier to minimize a further rise in fluid and/or engine coolant temperature and assist fluid
cooling.

Cruise

When speed control is activated, the

TCM

receives a speed control active message on the high speed

CAN

bus. The

TCM

activates a speed

control map which minimizes up and down shifts.

Cruise mode is active when speed control is selected on and the transmission is in drive 'D' or sport 'S'. Unique cruise maps override the
current mode to provide a smooth driving feel and mode reselection.

Limp home

If a transmission fault is detected by the

TCM

, the

TCM

adopts a limp home strategy and a message 'TRANSMISSION FAULT LIMITED GEARS

AVAILABLE' is displayed in the message center. If the fault has an effect on engine emissions, the

MIL (malfunction indicator lamp)

in the

instrument cluster will also be illuminated.

In limp home mode, P, R and N functions operate normally (if the fault allows these selections) and the

TCM

locks the transmission in 3rd

gear to allow the driver to take the vehicle to a Jaguar dealer or approved repairer. Torque converter lock-up is disabled and reverse-lock-out
will not function.

If the vehicle is stopped and subsequently restarted in the limp home mode condition, the

TCM

operates normally until the fault which

caused the condition is detected again.

Coast

Coast mode provides earlier downshifts during coasting dependant on output shaft deceleration rate to improve driveability and refinement
by avoiding negative to positive driveline torque reversals transmission during the downshifts.

Fast Off Recognition

Fast off recognition is activated when the

TCM

detects that the driver has released the accelerator pedal quickly. This is detected by the

TCM

monitoring for a high level of negative pedal angle from

ECM

signals on the high speed

CAN

bus. If this condition is detected, the

TCM

holds the current gear ratio to allow the driver to complete the manoeuvre without the need for a downshift. The mode can remain active for
a predetermined length of time or if the driving style remains passive.

Fast off recognition mode assists vehicle stability and is used in conjunction with a lateral acceleration input during cornering to maintain
the current gear until the corner is negotiated.

Uphill and Trailer

Uphill and trailer mode can be active when the transmission is operating in normal or sport `modes. When the vehicle is pulling a trailer or
driving up an incline, the

TCM

detects the increased resistance by monitoring engine torque and speed signals received from the

ECM

on the

high speed

CAN

bus and also transmission output shaft speed sensor signals. Uphill and trailer mode will provide downshifts to prevent a

drop in transmission torque output and maintain driving force.

Downhill

Downhill mode can be active when the transmission is operating in normal or sport modes. W hen the vehicle is descending an incline the

TCM

detects a reduction in resistance by monitoring engine torque and speed signals received from the

ECM

on the high speed

CAN

bus and

also transmission output shaft speed sensor signals. Downhill mode assists engine braking by selecting an appropriate gear reducing the
load required on the brakes.

Wide Throttle

Wide open throttle mode operates for part throttle upshifts and kick-down upshifts. It provides consistent wide open throttle upshift
performance under all driving conditions. The full engine speed range is used in all driving modes; normal, sport, hill modes and Jaguar
Sequential Shift. Compensation is used for delays (hydraulic and electronic) in gear change request to gear change start to provide smooth
changes and correct shift point correction.

Reverse Lock-Out

If the selector lever is moved from N to R and the vehicle is travelling forwards, reverse selection is prevented if the vehicle speed is 11
km/h (6.8 mph) or more. W hen reverse lock-out is activated, the clutch (C3) is released without energizing solenoid (SLC3), preventing the
transmission from selecting reverse gear.

TRANSMISSION FAULT STATUS

If the

TCM

detects a fault with the transmission system, it will enter a default (limp home) mode to prevent further damage to the

transmission and allow the vehicle to be driven. If possible reverse gear will be available and also 3rd gear only.

When a fault is detected a high speed

CAN

message is sent from the

TCM

and is received by the instrument cluster. The instrument cluster

illuminates the

MIL

(if required) and displays an applicable message in the message center.

For additional information, refer to:

Information and Message Center

(413-08 Information and Message Center, Description and Operation).

Some transmission faults may not illuminate the

MIL

or display a fault message, but the driver may notice a reduction in shift quality.

ENGINE SPEED AND TORQUE MONITORING

The

ECM

constantly supplies the

TCM

with information on engine speed and torque through messages on the

CAN

bus. The

TCM

uses this

information to calculate the correct and appropriate timing of shift changes.

If the messages are not received by the

ECM

, the

TCM

will implement a back-up strategy to protect the transmission from damage and

allow the vehicle to be driven.

In the event of an engine speed or torque signal failure, the transmission will adopt the electrical limp home mode with the transmission
operating in a fixed gear.