JAGUAR X308 1998 2.G Workshop Manual

In the event of a system fault, the TCM will adopt 'limp home' mode.
Electrical control
Refer to Section 307-01B.
Transmission Control Components
Transmission Control Module (TCM)
The TCM controls the transmission internal components thus determining gear selection and shift pattern.

The TCM is located in the same housing as the engine control module (ECM) and is accessed in the same manner. With the
two connectors unplugged the TCM may be withdrawn, complete with mounting bracket. The mounting bracket is secured to
the TCM by 2 locknuts.
Operation
CAUTION: Disconnection of OTHER contro l module connectors and / or the vehicle battery, may introduce fault codes
(DTCs). Following rectification and reconnection, ensu re that no induced codes exist in the TCM memory.
The TCM processes input and output in both analogue and di gital form which may be summarized in four categories:
Input Signals
Gear selector position (Dual Linear Switch x 4 inputs see 307.05) Transmission oil temperature Kickdown Speed sensor #1 Speed sensor #2 Mode switch

CAN Input Signals
Traction status ABS malfunction ABS status Engine torque status Throttle position Accelerator pedal position Engine torque reduction confirmation Engine speed Engine coolant temperature Cruise status OBDII fault code clear request Throttle malfunction warning RED or AMBER All road wheel speeds Token for network status ECM Token for network status INST Token for network status ABS Diagnostic data in from external device (PDU)
Output Signals
Solenoid valve 1 <-> 2 and 4 <-> 5 shift Solenoid valve 2 <-> 3 shift Solenoid valve 3 <-> 4 shift Solenoid valve converter lock-up clutch Control valve - modulating pressure Control valve - shift pressure
CAN Output Signals
Engine torque reduction request MIL status (whether present DTC should operate MIL) Transmission input speed Transmission output speed Converter slip Kickdown status Gear position (actual) Gear position (selected) Gear selection fault Converter lock-up status Current selected shift map Transmission oil temperature Transmission malfunction Pecus flag (state of current TCM program) Target for next gear position Gear shift torque transfer progress at shift MIL status (response to activate the MIL relevant to a DTC) OBDII fault code clear acknowledgement Transmission DTCs (P codes) Token for network status TCM Diagnostic data out to external device (PDU)
Emergency Running (elect ronic limp-home mode)
The TCM constantly monitors the transmissi on for faults. In the event of a problem the TCM will adopt the limp-home mode, in which the gear currently held remains engaged, until P is selected. The modulati ng and shift pressures will increase to
maximum and converter lock-up will be inhibited.
Following the selection of P , the only ratios available will be 2 (irrespective of forward ratio manual selection) and R .
With the vehicle at rest, the procedure to manually select is as follows:
1. 1. Select P .

2.2. Switch OFF the ignition.
3. 3. Wait 10 seconds.
4. 4. Start the engine.
5. 5. Select R (reverse will be selected).
6. 6. Select D ( 2 will be selected).
The limp-home mode will be retained until the fault is remedied or the fault code has been erased. Intermittent faults may
be cleared by cycling the ignition OFF/ON. In certain cases the component may need to be operated before the fault code is
cleared eg. a shift solenoid.
Emergency Running (mechanica l/hydraulic limp-home mode)
Should slip be detected, due to a mechanical failure or loss of pressure, the transmission will either shift to, and hold 3 or
shift to, and hold, the last gear which was known to be alright. This condition may be cleared by cycling the ignition OFF/ON
following mechanical repair.
The operator will be made aware of certain faults by a warning message on th e instrument cluster.
Data concerning OBDII related transmission failures is stored in the ECM for access via the J1962 socket.
Safety Functions
These functions are designed to safeguard against inappropriate actions by the operator as well as system malfunctions.
The electrical and diagnostic system has been designed such that system integrity is protected at all times, the safety
concept being based on th e following three points.
1. 1. The hydraulic system has 'fail-safe' characteristics regardin g its electrical operation, such that should the power
supply be lost to the electro-hydraulic actuators the transmission will initiate a limp-home mode.
2. 2. Recognition of critical shift operation by monitoring the last element in the signal path, ie the solenoid valve, and
checking by means of redundant me asured variables relative to engine, transmission and road speeds.
3. 3. Each time the vehicle is started there is a check on the entire safety hardware and the associated program parts
and signal paths. A malfunction in this part of the system, or triggering of the safety circuit, is communicated to
the operator by a warning messag e on the instrument cluster.
CAUTION: Do not engage R or P with the vehicle in motion.
Should R be engaged with the vehicle in forward motion, the transmission will default to neutral until either the vehicle
speed decreases to 4 mph or D is selected.
Towing
The vehicle may be towed provided that:
Selector in position N Speed < 50 kph Distance < 50 km
System Functions
'J' Gate Layout

Range Selection
The 'J' gate selector lever is connected to the transmission via a cable which operates the transmission selector shaft
between positions P R N D only. The shift lever disconnects from the cable when the lever is moved across the gate from D
to 4 .
Movement of the lever between P R N D manu ally controls the flow of transmission fluid, the TCM having control of the
forward gear selected in D .
Movement of the lever to 4 , 3 and 2 positions does not manu ally modify the fluid flow, the TCM detects these positions
using the DLS and controls the ratios electronically by energizing solenoids.
Shift Point Control
The gearshift points are controlled by the TCM, as a function of the output speed, engine load, engine speed, selector
position and shift program selected. The operator has control over the shift points via the shift lever, throttle pedal
movement, kickdown function and mode switch.
Mode Switch
This switch allows operator selection of two base shift modes; Normal and Sport; th e switch being illuminated when Sport is
selected. This function alters the values in the TCM shift point calculations.
Shift Programs
Upon encountering the following conditions, the TCM will auto matically modify the Normal or Sports shift map to enhance
the operation of the vehicle:
1. 1. Traction: When traction intervention is active.
2. 2. Hot mode: Extreme engine/transmission temperatures.
3. 3. Gradient: Under specific speeds and loads.
4. 4. Manual: Driver initiated override of the normal shif t map when the LH side of the 'J gate' is used.
Traction
When traction or stability control (engine or brake system de rived) is operational the TCM will implement the traction map
to maximize control of wheel slip.
Gradient
The gradient function is intended to enhance vehicle drivea bility when climbing a gradient or towing. The TCM will
implement the function when increased driving resistance is de tected, and provides enhanced driveability, additional cooling

and/or increased performance as appropriate.
Serial Communications Interfaces
Controller Area Network (CAN)
The TCM is an integral part of the CAN system which facilita tes the interchange of real-time data between control modules
and sensors; refer to 303-14 fo r a full description of CAN.
Transmission Pressure Regulators and Shift Solenoids Circuit Diagram

ItemPart NumberDescription
1—Transmission oil temperature sensor
2—Switch
3—Shift solenoid 1 <-> 2, 4 <-> 5
4—Shift solenoid 2 <-> 3

Speed Sensor / TCM Circuit Diagram

Connector Pins Identification
Connector Pin Identity Chart for EM061
5—Shift solenoid 3 <-> 4
6—TCC pressure regulator
7—Modulation pressure regulator
8—Shift pressure regulator
9—Engine compartment fuse box
10—Transmission control module
11—Transmission
ItemPart NumberDescription
1—n2 speed sensor
2—n3 speed sensor
3—Engine compartment fuse box
4—Transmission control module
5—Transmission

Connector Pin Identity Chart for EM062

Connector Pin Identity Chart for CC008
Pin NumberCircuitCircuit Function
001Not used
002Kickdown SW
003Mode SW
025DLS position WO
026DLS position W1
027DLS position W2
028DLS position W3
029Ignition B+
030Power ground (common to DLS)
Pin NumberCircuitCircuit Function
012n2 speed signal
013Speed sensor +ve
014Solenoid 1 <-> 2 and 4 <-> 5
015Solenoid 3 <-> 4
016Solenoid 2 <-> 3
017Torque converter solenoid
033Speed and temperature sensor ground
034Temperature sensor
035n3 speed signal
036Pressure regulator Modulating signal
037Pressure regulator Shift signal
038Solenoid and pressure regulator +ve
040CAN link -ve
041CAN link +ve

Connector Pin Identity Chart for GB001

Connector Pin Identity Chart for EM044
Pin NumberCircuitCircuit Function
001DLS position W3
002Power ground (common to TCM)
003Ignition B+
004Neutral (BPU)
005Park / neutral (ECM)
006DLS position W1
007DLS position WO
008DLS position W2
Pin NumberCircuitCircuit Function
001n3 speed signal
002Pressure regulator MD signal
003n2 speed signal
004Temperature sensor
005Not used
006Solenoid and pressure regulator +ve
007Speed sensor +ve
008Solenoid 2 <-> 3
009Solenoid 3 <-> 4
010Pressure regulator SD signal
011Torque converter solenoid
012Speed and temperature sensor ground
013Solenoid 1 <-> 2, 4 <-> 5

Pin NumberCircuitCircuit Function
001n3 speed signal
002Pressure regulator MD signal
003n2 speed signal
004Temperature sensor
005Solenoid 1 <-> 2, 4 <-> 5
006Solenoid and pressure regulator +ve
007Speed sensor +ve
008Solenoid 2 <-> 3
009Solenoid 3 <-> 4
010Pressure regulator SD signal
011Torque converter solenoid
012Speed and temperature sensor ground

Automatic Transmission/Transaxle - 4.0L SC V8 - AJ26 - Diagnostic
Strategy
Diagnosis and Testing
Symptom Chart
Symptom Chart
Special Tool(s)

Digital multimeter

Generic scantool
SymptomPossible SourcesAction
DTC P0740 Torque converter clutch system
electricalHarness fault
Connector pins(s) bent , loose or corroded
*
*GO to Pinpoint Test A
*
DTC P0740 Torque converter clutch system stuck
onTorque converter clutch stuck on
*GO to Pinpoint Test B
*
DTC P1744 Torque converter clutch system stuck
offTorque converter clutch stuck off
*GO to Pinpoint Test B
*
DTC P0702 Transmission control system electricalHarness fault
High side switch (FET) fault
Connector pins(s) bent , loose or corroded
*
*
*GO to Pinpoint Test C
or D
*
DTC P0753 Shift solenoid A electricalHarness fault
Solenoid open circuit
Solenoid short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test C *
DTC P0758 Shift solenoid B electricalHarness fault
Solenoid open circuit
Solenoid short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test C *
DTC P0763 Shift solenoid C electricalHarness fault
Solenoid open circuit
Solenoid short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test C *
DTC P0748 Pressure control solenoid electricalHarness fault
Pressure regulator open circuit
Pressure regulator short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test D *
DTC P1748 Pressure control solenoid B electricalHarness fault
Pressure regulator open circuit
Pressure regulator short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test D *
DTC P0702 Transmission control system electricalHarness fault
Speed sensor voltage supply out of
tolerance Connector pins(s) bent , loose or corroded
*
*
*GO to Pinpoint Test E
*
DTC P0715 Input / turbine speed sensor circuit
malfunctionSpeed sensor n2 or supply open circuit
Speed sensor n3
Harness fault
Connector pins(s) bent , loose or corroded
*
*
*
*GO to Pinpoint Test F
*
DTC P1601 Internal control module computer errorFaulty TCM
*GO to Pinpoint Test G *