Diagnosis - Automatic Transmission Land Rover Freelander L314

GENERAL

The JATCO JF506E automatic gearbox is an electronically controlled, five speed gearbox which incorporates software to enable the gearbox to operate as a semi-automatic gearbox. The transmission, previously known as Steptronic', is designated CommandShift from 2003 model year.

The gearbox can be operated as a conventional automatic gearbox by selecting P, R, N, D, 4, 2 or 1 on the selector lever. Moving the selector mechanism across the gate to the S/M position, sends a signal to the Electronic Automatic Transmission (EAT) ECU and puts the gearbox into sport/manual mode.

In sport mode, the gearbox still operates as a conventional automatic transmission, but the unit becomes more responsive to driver demands. Lower gears will be held longer and the transmission will downshift more readily. This gives increased acceleration and improves vehicle response.

When in sport mode, if the selector lever is moved to the + or - positions, the system will automatically change to operate in manual mode. Manual gear changes can be performed sequentially using the selector lever. Movement of the selector lever in the forward (+) direction changes the gearbox up the ratios and movement in a rearward (-) direction changes the gearbox down the ratios.

Gearbox operation is controlled by the EAT ECU and the Engine Control Module (ECM) which communicate via a Controller Area Network (CAN) Bus. The EAT ECU receives information from the ECM and gearbox sensors to calculate the appropriate gear ratio for the conditions and controls solenoid valves to operate the gearbox as required.

The advantages gained with the electronically controlled gearbox are smoother gear changes, quicker and more accurate gear change scheduling and reduced fuel consumption through improved engine/gearbox speed matching.

COMMANDSHIFT JATCO AUTOMATIC GEARBOX

The JATCO five speed automatic gearbox is similar to conventional electronically controlled transmissions but provides the driver with an additional manual mode feature. Manual mode allows the driver to electronically select the five forward gear ratios and operate the gearbox as a semi-automatic manual gearbox.

The individual gear ratios are achieved through three planetary gear sets. The components of the planetary gear sets are driven or locked by means of four multi-plate clutches, two multi-plate brakes, one brake band and two one-way clutch assemblies. Torque is transmitted from the gearbox to the final drive through a reduction gear.

GEARBOX CASING

Refer to JATCO Automatic Gearbox illustration. (Scheme 115)

The gearbox casing contains the input shaft transmitting the power into the drive train. The drive train is made up of the planetary gear sets and clutches.

The clutches and brake bands control which elements of the planetary gear sets are engaged and their direction of rotation, to produce the P and N selections, five forward ratios and one reverse gear ratio. See GEAR RATIOS table. Power output is from the drivetrain through a reduction gear into a differential.

GEAR RATIOS

VALVE BLOCK & SOLENOID VALVES

Refer to JATCO Automatic Gearbox - Valve Block and Solenoids illustration. (Scheme 116)

The gearbox uses nine solenoid valves located on the valve block. The solenoid valves are energized/de-energized by the EAT ECU to control the gearbox fluid flow around the gearbox to supply clutches, brakes and brake band (gear change scheduling), fluid to the torque converter, lubrication and cooling.

Each solenoid valve is controlled separately by the EAT ECU. All nine solenoid valves can be classified into two types by their operating mode. Three of them are duty solenoid valves and the remaining six are ON-OFF solenoid valves.

Each solenoid valve consists of an internal coil and needle valve. A voltage is passed through the coil of the solenoid to actuate the needle valve. The needle valve opens and closes the fluid pressure circuits. ON-OFF solenoid valves close the fluid pressure circuits in response to current flow.

Duty solenoid valves repeatedly turn ON and OFF in 50 Hz cycles. This opens and closes the fluid circuits allowing a higher level of control on the circuits. For example, smooth operation of the lock-up clutch in the torque converter to eliminate harsh engagement/disengagement.

All of the solenoid valves are supplied with battery voltage and an earth path by the EAT ECU.

ON/OFF SOLENOID VALVES

The ON/OFF solenoid valves are

1. Shift solenoid valve A.
2. Shift solenoid valve B.
3. Shift solenoid valve C.
4. Low clutch timing solenoid valve.
5. Reduction timing solenoid valve.
6. 2-4 brake timing solenoid valve.

The EAT ECU switches the on/off solenoid valves to open and close in response to vehicle speed and throttle opening.

Shift solenoid valves A, B and C are used to engage the different gear ratios within the gearbox. The position of these solenoid valves at any one time determines the gear selected. See SHIFT SOLENOID VALVE ACTIVATION table.

SHIFT SOLENOID VALVE ACTIVATION

The reduction timing solenoid valve, low clutch timing solenoid valve and 2-4 timing solenoid valve are used by the EAT ECU to control the timing of the gear shift changes.

These solenoid valves carry out three main functions

1. Shift Timing Control For some shifts these three solenoid valves are used to assist line pressure control or 2-4 brake pressure control.
2. Line Pressure Cut Back When the gearbox takes up the drive there should be a high line pressure present. The EAT ECU controls the low clutch timing solenoid valve which is related to the vehicle speed in order to switch the fluid circuit of the line pressure to on or off therefore controlling cut back.
3. Reverse Inhibition If the vehicle exceeds 6 mph (10 km/h) and Reverse (R) is selected, the EAT ECU switches the low clutch timing solenoid valve on. This drains the gearbox fluid from the reverse clutch, therefore the clutch will be unable to engage.

DUTY SOLENOID VALVES

The duty solenoid valves are

1. Lock-up duty solenoid valve.
2. Line pressure duty solenoid valve.
3. 2-4 duty brake solenoid valve.

The lock-up duty solenoid valve is used by the EAT ECU to control the lock-up of the torque converter depending upon the vehicle speed and throttle position.

The EAT ECU will actuate the lock-up solenoid valve, which operates the lock-up control valve to direct fluid to either lock or unlock the torque converter.

The line pressure duty solenoid valve and 2-4 duty brake solenoid valve are used by the EAT ECU to control fluid line pressure in the gearbox. The EAT ECU calculates the line pressure by using the engine speed, vehicle speed and throttle angle.

The EAT ECU then actuates the solenoid valves accordingly to achieve the required line pressure.

The solenoid valves can fail in the following ways

1. Open circuit.
2. Short circuit to 12 or 5 volts.
3. Short circuit to earth (ground).

In the event of a solenoid valve failure any of the following symptoms may be observed

1. Gearbox selects fourth gear only (shift solenoid valve failure).
2. Gearbox will not upshift to fourth gear (timing solenoid valve failure).
3. Increased fuel consumption and emissions (lock-up solenoid valve failure).
4. Gear shifts will have no torque reduction therefore gear changes will be very harsh (line pressure duty solenoid valve failure).
5. No pressure control will occur therefore gear changes from fifth gear will be very harsh (2-4 brake duty solenoid valve failure).

1st Gear (Drive Selected)

On 1st gear selection, the low clutch and the reduction brake are engaged. (Scheme 90) During acceleration in 1st gear, the low one-way clutch and the reduction clutch are locked. Power flows from the input shaft to the rear sun gear to rotate it clockwise and the rear pinion gear rotates counterclockwise. The rear internal gear tries to rotate clockwise. However, because the internal gear is connected to the low one-way clutch through the low clutch, the rear internal gear cannot rotate. Consequently, the rear planetary carrier and the output gear rotate clockwise. The output gear rotation is transmitted to the reduction internal gear by the idler gear. The reduction brake locks the reduction sun gear. The reduction gear rotates clockwise and makes the reduction planetary carrier rotate clockwise simultaneously. The reduction gear rotates clockwise and transmits the power to the final drive and out to the road wheels.

Scheme 90

2nd Gear (Drive Selected)

On 2nd gear selection, the low clutch, the 2-4 brake, and the reduction brake are engaged. (Scheme 91) During acceleration in 2nd gear, the reduction one-way clutch is locked. Power flows from the input shaft to the rear sun gear to rotate it clockwise and the rear pinion gear rotates counterclockwise. The 2-4 brake locks the front sun gear. The front pinion gear rotates clockwise to force the front planetary carrier to rotate clockwise. The driven power rotates the front internal gear clockwise. The output gear rotates faster due to the front internal gear rotation. The output gear rotation is transmitted to the reduction gear. The reduction gear rotates clockwise and transmits the power to the road wheels in the same way as 1st gear.

Scheme 91

3rd Gear (Drive Selected)

On 3rd gear selection, the high clutch, the low clutch, and the reduction brake are engaged. (Scheme 92) During acceleration in 3rd gear, the reduction one-way clutch is locked. Power flows from the input shaft in a clockwise direction to the high clutch through the front planetary carrier. The front planetary carrier is connected to the rear internal gear by the low clutch. The rear internal gear rotates clockwise at the same speed as the input shaft. The rear sun gear rotates clockwise at the same speed because it is connected to the input shaft and the rear internal gear. The rear pinion does not rotate. The rear planetary carrier rotates in the same direction and speed as the input shaft. The power flow from the rear planetary carrier is transmitted to the reduction gear via the output gear, idler gear, reduction internal gear, and the reduction planetary carrier. The power is then transmitted to the road wheels in the same way as 1st gear.

Scheme 92

4th Gear (Drive Selected)

On 4th gear selection, the high clutch, 2-4 brake, and the reduction brake are engaged. (Scheme 93) During acceleration in 4th gear, the reduction one-way clutch is locked. Power flows from the input shaft to the front planetary carrier to rotate clockwise by the high clutch. The 2-4 brake locks the front sun gear. The front pinion gear rotates clockwise and forces the front planetary carrier to rotate clockwise simultaneously. This allows the front internal gear to rotate clockwise and transmit power to the reduction internal gear via the output gear and idler gear. The rotational speed of the planetary carrier is faster than 3rd gear because of the rotation of the internal gear. Power is then transmitted to the road wheels in the same way as 1st gear.

Scheme 93

5th Gear (Drive Selected)

On 5th gear selection, the high clutch, direct clutch, and the 2-4 brake are engaged. (Scheme 94) Power flows from the input shaft and is transmitted to the reduction internal gear by the high clutch in the same way as in 4th gear. This power is transmitted through the reduction sun gear, final drive and direct clutch to drive the road wheels.

Scheme 94

Reverse Gear

On reverse gear selection, the reverse clutch, the low and reverse brake, and the reduction brake are engaged. (Scheme 95) Power flows from the input shaft to the reverse clutch and the front sun gear. The low and reverse brake is engaged, locking the front planetary carrier in position. When the front sun gear rotates clockwise, the front planetary carrier remains locked. The front pinion gears rotate counterclockwise, forcing the internal gear and output gear to rotate counterclockwise. The output gear rotation is transmitted to the reduction internal gear by the idler gear. The reduction brake locks the reduction sun gear, the reduction planetary carrier rotates in the reverse direction to the forward ranges and transmits drive to the road wheels through the final drive.

Scheme 95

Torque Converter Operation

The torque converter is located inside the torque converter housing which is on the engine side of the gearbox casing.

The torque converter acts as the coupling element between the engine and gearbox. The driven power from the engine is transmitted hydraulically and mechanically in certain gears and operating conditions, through the torque converter lock-up clutch to the gearbox. The torque converter is connected to the engine by a drive plate.

The torque converter consists of an impeller, stator and turbine. (Scheme 96) The engine drives the impeller, while the turbine drives the gearbox.

The stator is situated between the impeller and turbine on a one-way clutch. The impeller picks up fluid and throws it out into the turbine, thereby causing it also to rotate and transmit power.

The stator redirects the fluid thrown back by the turbine, so that it re-enters the impeller in the same direction of rotation as the impeller and at the most efficient angle.

The one-way clutch prevents the stator from moving backwards, so that this accurate redirection of fluid can be achieved. When the engine is idling the impeller throws out very little fluid. The turbine is not forced to turn, and the power is not transmitted to the gearbox.

As engine speed increases the impeller throws out more fluid. The turbine begins to turn and picks up speed as the engine speed rises. As the speed of the turbine increases the fluid is thrown against the back of the stator, causing it to turn in the same direction.

When turbine speed approaches impeller speed, centrifugal force in both units is almost equal and all three components move at nearly the same rate. This is called the COUPLING POINT.

The torque multiplication or drive ratio varies until a one to one coupling point is reached.

To achieve the power required to climb a hill, the driver depresses the accelerator pedal and the torque converter reacts by increasing the torque multiplication.

When driving on a flat road at cruising speed, the power required is not as great and therefore, the torque converter stays at one to one.

Scheme 96

Torque Converter Lock-Up Mechanism

In a torque converter there is always a certain amount of slip between the impeller and turbine. This will contribute to a reduction in fuel economy especially during high speed cruising.

This is eliminated by the torque converter lock-up mechanism. The lock-up mechanism is attached to the turbine and controls a lock-up clutch which is integral with the torque converter.

The lock-up mechanism comprises a lock-up solenoid valve, a lock-up control valve and a lock-up clutch.

The lock-up control is provided by the EAT ECU which operates the lock-up solenoid valve. The EAT ECU controls lock-up clutch engagement and release according to the lock-up schedule programmed into the ECU and the vehicle speed and throttle angle.

The lock-up mechanism operates with the gearbox in Drive (normal mode 4th and 5th gears) and in manual 4th and 5th gears. In an emergency condition when high fluid temperatures are reached, the EAT ECU can also operate the lock- up mechanism in 2nd and 3rd gears to help reduce fluid temperatures.

In addition to the lock and unlock conditions, the lock-up control can also initiate smooth lock-up, coast lock-up and lock-up prohibition control.

Smooth lock-up minimizes lock-up shock by smoothly and slowly engaging the lock-up clutch.

Coast lock-up control maintains the lock-up condition after the throttle pedal has been released in the lock-up range at certain high speed driving. This prevents the lock-up control switching between the locked and unlocked condition caused by repeated on-off use of the throttle pedal.

Lock-up prohibition control prevents clutch lock-up within the range if the fluid temperature is below 40°C (104°F). This promotes faster warm-up of the gearbox fluid. This strategy is also used by the EAT ECU to prevent lock-up in 1st gear, park, reverse and neutral ranges.

Unlock Condition

The unlock release pressure is supplied via the control valve to the lock-up clutch. (Scheme 97) The pressure forces the clutch mechanism away from the torque converter and moves the lock-up mechanism into the unlock condition. The torque converter pressure is decayed to the drain port, removing the applied pressure from the torque converter, allowing the clutch mechanism to move.

Scheme 97

Lock-Up Condition

The EAT ECU operates the lock-up solenoid, which in turn supplies pilot pressure to the control valve. (Scheme 98) The control valve moves under the influence of the pilot pressure, blocking the release pressure feed to the lock-up clutch and re- directing it to the other side of the clutch mechanism.

With the release pressure removed, the lock-up clutch moves and engages with the torque converter, moving the lock- up mechanism into the locked condition.

Scheme 98

Smooth Lock-Up

Smooth lock-up occurs as the mechanism moves from the unlock to the locked condition. Torque converter release pressure is lowered gradually preventing a sudden lock-up clutch engagement, reducing lock-up shock.

The lock-up solenoid is a driven duty solenoid operating at 50 Hz. The lock-up control valve has a pressure regulation device which reacts to torque converter release pressure and solenoid pilot pressure.

As the solenoid is operated, the pilot pressure is gradually applied to the control valve. This moves the valve, partially exposing the release pressure to a drain port.

The control valve is moved against an opposing spring by the increasing pilot pressure. The release pressure is decayed proportionally in response to the increasing pilot pressure allowing the clutch to smoothly engage with the torque converter.

FLUID COOLING

Fluid cooling is performed by a dedicated fluid cooler for the gearbox. (Scheme 99) On KV6 and Td4 cold climate models, a water cooled fluid cooler is located at the front of the gearbox. On Td4 hot climate models an air blast cooler, which replaces the water cooled cooler is located in the front LH wheel arch.

The fluid cooler is located on a bracket at the front of the gearbox. The cooler comprises cores which allow fluid to flow across from one side of the cooler to the other. Each core is surrounded by a water jacket which allows engine coolant to flow around the cooler.

The cooler is connected to the gearbox by metal pipes and flexible hoses, and to the engine cooling system by coolant hoses.

The gearbox fluid flows from the gearbox to the upper connection on the fluid cooler. The fluid then flows through the cores in the cooler which are surrounded by engine coolant which cools the gearbox fluid. The fluid exits the fluid cooler via the lower connection and is returned to the gearbox.

The engine coolant flows from the engine oil cooler (on all except NAS and Gulf States models), or the cylinder block (on NAS and Gulf States models), to the lower coolant connection on the fluid cooler. The coolant exits the cooler via the upper connection and flows to the thermostat housing.

Scheme 99

SENSORS

Note. The EAT ECU sets correct gear change scheduling using three speed signal inputs: intermediate speed, turbine speed and vehicle speed in conjunction with a throttle position signal from the ECM.

Intermediate Speed Sensor

The intermediate speed sensor is located within the gearbox. (Scheme 100) The EAT ECU uses this sensor to ensure correct gear engagement and to monitor the amount of slip within the gearbox.

The EAT ECU calculates the slip within the gearbox by comparing the difference between the inputs from the intermediate speed sensor and the turbine speed sensor.

The intermediate speed sensor detects the output gear rotation speed and sends an electrical output to pin 51 of the EAT ECU which also supplies an earth path for the sensor on ECU pin 20.

The sensor is an inductive sensor that produces a sinusoidal output at a frequency of 54 pulses per revolution of the output gear.

The intermediate speed sensor can fail in the following ways

1. Sensor open circuit.
2. Short circuit to 5 or 12 volts.
3. Short circuit to earth.

The EAT ECU will detect sensor failure if the vehicle speed exceeds 25 mph (40 km/h) and the sensor output is equivalent to less than 600 rev/min for two seconds.

In the event of an intermediate speed sensor signal failure any of the following symptoms may be observed

1. Upshift to 5th gear inoperative.
2. Torque reduction request from the EAT ECU to the ECM inoperative.

A failure of the sensor will generate a "P" code which can be retrieved using TestBook/T4 or any Keyword 2000 diagnostic tool.

Scheme 100

Turbine Speed Sensor

The turbine speed sensor is located within the gearbox and is used by the EAT ECU to monitor the input shaft speed. (Scheme 101) The EAT ECU uses this sensor to ensure the correct gear ratio is selected and to ensure that there is not excessive slip within the gearbox drive train.

The turbine speed sensor detects the input shaft speed (turbine speed) and sends an electrical output to pin 24 of the EAT ECU which also supplies an earth path for the sensor on ECU pin 20.

The sensor is an inductive sensor that produces a sinusoidal output at a frequency of 36 pulses per revolution of the input shaft.

The turbine speed sensor can fail in the following ways

1. Sensor open circuit.
2. Short circuit to 12 or 5 volts.
3. Short circuit to earth.

The EAT ECU will detect sensor failure if the vehicle speed exceeds 25 mph (40 km/h) and the engine speed is above 1300 rev/min, but the turbine speed is below 600 rev/min for two seconds.

In the event of a turbine speed sensor signal failure any of the following symptoms may be observed

1. Upshift to 5th gear inoperative.
2. Torque reduction request from the EAT ECU to the ECM inoperative.

A failure of the sensor will generate a "P" code which can be retrieved using TestBook/T4 or any Keyword 2000 diagnostic tool.

Scheme 101

Vehicle Speed Sensor

The vehicle speed sensor is located within the gearbox. (Scheme 102) The EAT ECU uses this sensor to monitor the rotational speed of the parking gear and calculate this reading into a vehicle speed. The EAT ECU also monitors the vehicle speed using a signal from the ABS ECU.

The vehicle speed sensor detects the parking gear rotation speed and sends an electrical output to pin 5 of the EAT ECU which also provides an earth path for the sensor.

The sensor is an inductive sensor that produces a sinusoidal output at a frequency of 18 pulses per revolution of the parking gear.

The EAT ECU uses the signal to calculate the following

1. Amount of engine torque reduction required during gear changes.
2. Notify the EAT ECU when the vehicle is stationary, for creep control.

The vehicle speed sensor can fail the following ways

1. Sensor open circuit.
2. Sensor short circuit to 12 or 5 volts.
3. Sensor short circuit to earth.

The EAT ECU will detect sensor failure if the ABS ECU speed signal is more than 25 mph (40 km/h) but the vehicle speed sensor reading is less than 3 mph (5 km/h) for more than two seconds.

In the event of a vehicle speed sensor signal failure any of the following symptoms may be observed

1. Upshift to 5th gear inoperative.
2. Torque reduction request from the EAT ECU to the ECM inoperative.

If a failure of the vehicle speed sensor occurs and the ABS ECU speed signal is functional, the EAT ECU will control gear shifting using the ABS ECU signal.

If both the vehicle speed sensor and the ABS ECU speed signals fail, the EAT ECU will lock the gearbox in fourth gear (fail-safe mode) and inhibit torque converter lock-up control.

Scheme 102

Fluid Temperature Sensor

The fluid temperature sensor is located within the gearbox on the valve block. (Scheme 103) The EAT ECU uses this sensor to monitor the gearbox fluid temperature.

When the fluid is cold, the EAT ECU changes gear at higher engine speeds to promote faster fluid warm-up. If the fluid temperature becomes too high, the EAT ECU transmits a cooling request on the CAN link to the ECM to operate the cooling fans.

The fluid temperature sensor has an electrical output to pin 39 of the EAT ECU which also provides an earth path for the sensor.

The fluid temperature sensor is a negative temperature coefficient sensor. As the temperature rises, the resistance in the sensor decreases. As temperature decreases, the resistance in the sensor increases and the output voltage to the EAT ECU changes in proportion.

The output voltage from the sensor is in the range of 0-2.5 Volts with the lower voltage representing the highest temperature.

The change in resistance is proportional to the temperature of the gearbox fluid. See FLUID TEMPERATURE SENSOR RESISTANCE VALUES table. From the resistance of the sensor, the EAT ECU calculates the temperature of the gearbox fluid. Should the fluid temperature sensor fail the EAT ECU uses the last recorded EAT ECU value as a default value.

FLUID TEMPERATURE SENSOR RESISTANCE VALUES

The fluid temperature sensor can fail in the following ways

1. Sensor open circuit.
2. Short circuit to 12 or 5 volts.
3. Short circuit to earth.

The EAT ECU will detect temperature sensor failure when the vehicle speed exceeds 12.5 mph (20 km/h) and the temperature sensor provides a reading of less than -30°C (-22°F). In the event of a fluid temperature sensor signal failure any of the following symptoms may be observed

1. Upshift to 5th gear inoperative.
2. Torque reduction request from the EAT ECU to the ECM inoperative.

Scheme 103

SELECTOR & INHIBITOR SWITCH

The selector and inhibitor switch is located on the selector shaft on top of the gearbox and connected to the main harness by a 10 pin connector (C0244). (Scheme 104)

While the ignition is on, the selector and inhibitor switch receives a battery voltage power feed from the main relay. In some markets, in order to illuminate the LED module whenever the key is in the ignition switch, the selector and inhibitor switch also receives a battery voltage power feed from an illumination relay installed behind the center console.

Where fitted, operation of the illumination relay is controlled by the passive coil on the ignition switch. When the key is installed in the ignition switch the illumination relay energizes to connect the power feed to the selector and inhibitor switch. When the main relay is energized by the ECM, the illumination relay de-energizes and the power feed to the selector and inhibitor switch is taken from the main relay.

The EAT ECU and the LED module are provided with a voltage output from the selector and inhibitor switch that corresponds with the gear position the driver has selected. Seven sets of contacts in the selector and inhibitor switch which are operated by the selector shaft. Each set of contacts corresponds to one of the seven selector lever positions (PRND421). Only one set of contacts will supply battery voltage to the EAT ECU and the LED module at any one time. The EAT ECU monitors the switch outputs every 10 ms.

A pair of contacts are provided for the crank inhibit circuit. The contacts are only closed when the selector lever is in the Park and Neutral positions.

The two contacts are wired in series with the immobilization ECU. When the selector lever is in any position other than Park or Neutral, the feed from the ignition switch to the immobilization ECU is broken by the open contacts, preventing starter motor operation.

In the event of a selector and inhibitor switch signal failure, any of the following symptoms may be observed

1. Upshift to 5th gear inoperative.
2. Torque converter lock-up inoperative.
3. Torque reduction request from the EAT ECU to the ECM inoperative.
4. Cranking disabled if fault is on the two inhibitor switch contacts.

Scheme 104

Gear Selector Lever

The gear selector lever assembly comprises a shift lock solenoid, a key interlock mechanism (if fitted), an LED module and a sport/manual switch. (Scheme 105)

A nylon cast plate provides the location for the selector lever components. The plate is secured to the floor pan with six integral studs and nuts. A rubber boot protects the assembly from dirt and moisture under the vehicle and also isolates vibrations from the lever.

The selector lever is attached to a gimbal mounting which allows gear selection of PRND421 in a forward and backward direction and selection between automatic and sport/manual in a left and right transverse direction. When sport/manual mode is selected, the lever can be moved in a forward or backward direction to select (+) or (-) for manual operation.

There are seven selector lever positions

1. P (Park) Prevents the vehicle from moving by locking the gearbox.
2. R (Reverse) Select only when vehicle is stationary and the engine is at idle.
3. N (Neutral) No torque transmitted to the drive wheels.
4. D (Drive) This position uses all five forward gears. Normal position selected for conventional driving.
5. 4 This position uses 1st to 4th gears only.
6. 2 This position uses 1st and 2nd gears only.
7. 1 This position uses 1st gear only.
8. S/M (Sport/Manual - CommandShift) This position uses all five gears as in Drive, but will shift up at higher engine speeds, improving acceleration.
9. (+) and (-) Movement of the selector lever in the +/- positions, when the selector lever is in the S/M position, will operate the gearbox in manual (CommandShift) mode, allowing the driver to manually select all five forward gears.

The selector lever position is displayed to the driver on the LED module in the center console and in the instrument pack and corresponds with the position of the selector lever. The LED module illumination and instrument pack display is determined by the selector and inhibitor switch assembly on the gearbox, with the exception of the S/M LED and the 'Sport' instrument pack display which are operated by a hall effect sensor located on the sport/manual switch.

All vehicles with an automatic gearbox incorporate an interlock solenoid at the bottom of the lever, which, when the ignition switch is in position II, prevents the lever being moved from Park unless the foot brake is applied.

In some markets, the gear selector lever also incorporates a key interlock mechanism, operated by the selector lever and a Bowden cable connected to the ignition key barrel. The mechanism prevents the ignition key being removed from the barrel unless the selector lever is in the Park position. The mechanism also prevents the selector lever moving from the Park position until the ignition switch has turned from position 0 to position I or above.

Scheme 105

Sport/Manual Switch

The sport/manual switch comprises a Printed Circuit Board (PCB) and connector socket which is located to the left of the selector lever and is an integral part of the selector lever assembly and cannot be serviced separately. The switch is connected to the main harness by a twelve pin connector. (Scheme 106)

The sport/manual switch has five proximity sensors which correspond to the D, N, 4 and +/- positions. The selector lever has two targets. An upper target is aligned with the DN4 sensors and the lower target is aligned with the +/- sensors.

When the selector lever is in the D position, the D sensor is aligned with the target and the EAT ECU receives a signal that D is selected. When the selector lever is moved to the S/M (sport) position, the target moves away from the sensor. This is sensed by the ECU which then initiates sport mode.

The sensors in the N and 4 positions inform the ECU that D has been deselected, but not to the S/M position, preventing the ECU from incorrectly initiating sport mode.

When the selector lever is moved to the S/M position, the target moves away from the D sensor. If the EAT ECU does not receive a signal from either the 4 or N sensors, it determines that sport has been selected. The lower target is positioned between the two sensors for +/- selection. If the selector lever is not moved to the +/- positions, the ECU keeps the gearbox in sport mode. If the ECU senses a signal from either the (+) or (-) sensor, it initiates manual mode and selects the manual gear selection requested. Manual mode will be maintained until the ECU senses a signal from the D sensor.

Scheme 106

Shift Interlock Solenoid

The shift interlock solenoid is controlled by the EAT ECU. When the ignition switch is in position II, with the selector lever in the Park position, the EAT ECU supplies a power feed to the shift interlock solenoid. The shift interlock solenoid energizes and extends a pin into the selector lever, locking the lever in Park.

While the selector lever is in Park, when the EAT ECU senses the brake pedal being pressed, it de-energizes the shift interlock solenoid and the solenoid pin retracts, allowing the selector lever to be moved. When the selector lever is in any position other than Park, the shift interlock solenoid remains de-energized after the brake pedal is released, and the lever is free to be moved through the remainder of the range.

LED Module

The LED module is located in the selector lever surround and is secured with two integral clips. The module is connected to the main harness by a 12 pin connector (C0675).

The LED module illuminates the applicable LED for the P, R, N, D, 4, 2, 1 and S/M positions. When the side lamps are switched on, all the LED's are illuminated at a low intensity, with the selected gear lever position LED illuminated at a higher intensity.

Selector Cable

The selector cable is a Bowden type cable that connects the selector lever to an input lever on the gearbox.

A "C" clip secures the outer cable to the selector lever assembly; the gearbox end of the outer cable is secured to a bracket on the gearbox by an integral clip. The inner cable is adjustable at the connection with the gearbox input lever.

Brake Switch

Brake Switch The brake switch is located on the pedal box below the fascia. The EAT ECU uses this switch to monitor brake pedal application status. The information is input to pin 43 of the EAT ECU on a hardwired connection from the switch.

The EAT ECU can allow the gearbox to apply more engine braking therefore slowing down the vehicle in a shorter distance and reducing brake pad wear. The EAT ECU achieves engine braking by applying the low and reverse clutches.

The brake switch can fail in the following ways

1. Switch open circuit.
2. Short circuit to 12 or 5 volts.
3. Short circuit to earth.

In the event of a brake switch signal failure, extra gearbox braking will not occur and the shift lock solenoid (if fitted) will not function.

Instrument Pack Displays

The instrument pack displays gearbox selection and fault information in the LCD and can illuminate the MIL for OBD emission related faults. (Scheme 107)and (Scheme 108).

The gearbox related displays in the instrument pack are controlled by the ECM which transmits CAN message signals to operate the lamps and the LCD.

Scheme 107

Scheme 108

Malfunction Indicator Lamp (MIL)

The Malfunction Indicator Lamp (MIL) is an Amber warning lamp located in the instrument pack. On all except NAS models, the warning lamp shows an engine silhouette. On NAS models the warning lamp shows a SERVICE ENGINE SOON legend. (Scheme 107)and (Scheme 108). The lamp is illuminated by a CAN message from the ECM on receipt of a CAN message from the EAT ECU.

Emission related faults are detected by the OBD feature in the EAT ECU and will illuminate the MIL in the instrument pack.

Liquid Crystal Display (LCD)

The Liquid Crystal Display (LCD) is located in a central position in the instrument pack. In addition to displaying the odometer and trip meter, the LCD also displays the current gearbox status. (Scheme 107)and (Scheme 108). For characters displayed and their definition see LCD CHARACTER DISPLAY DEFINITIONS table.

LCD CHARACTER DISPLAY DEFINITIONS

The EAT ECU transmits the selector lever position through the CAN bus to the ECM. The ECM processes this information and passes it to the instrument pack in the form of CAN messages to display the gearbox status.

If the gearbox develops a fault and adopts the limp home mode, the LCD will alternately display "F" and "4" to alert the driver that a fault has occurred and limp home mode is operational.

ELECTRONIC AUTOMATIC TRANSMISSION

The Electronic Automatic Transmission (EAT) ECU is located in the Environmental box (E-box) in the engine compartment, adjacent to the ECM. (Scheme 109) The ECU is connected to the vehicle wiring by a 54-pin connector (C0932).

The EAT ECU uses a FLASH Electronic Erasable Programmable Read Only Memory (EEPROM). This enables a new or replacement EAT ECU to be externally configured. EEPROM also allows the EAT ECU to be updated with new information and market specific data.

To input new information and market specific data the EAT ECU must be configured using TestBook/T4. The EEPROM allows the ECU to be reconfigured as many times as necessary to meet changing specifications and legislation.

The EAT ECU memorizes the signal values of the gearbox sensors and actuators. These stored values ensure optimum gearbox performance is achieved at all times.

This information is lost if battery voltage is too low, for example if the battery becomes discharged. The EAT ECU reverts to default readings on first engine start after a battery discharge or disconnection. The EEPROM facility in the ECU allows the stored values to be relearned, ensuring optimum gearbox performance.

If these signals are not within the EAT ECU stored parameters, the ECU will make adjustments to the operation of the gearbox through the actuators to provide optimum driveability and performance.

The inputs from the sensors constantly updates the EAT ECU with the current operating condition of both the gearbox and the engine. The ECU compares this current information with mapped information stored within its memory. The ECU will make any required adjustment to the operation of the gearbox through the following actuators

1. Gear control solenoid valves.
2. Lock-up solenoid valve.
3. Line pressure solenoid valve.

The EAT ECU also interfaces with the following

1. Engine Control Module (ECM) via the CAN.
2. Instrument pack via the CAN.
3. Diagnostic socket via the ISO 9141 K line.

Scheme 109

EAT ECU CONNECTOR C0932 PIN DETAILS

For EAT ECU 54-pin harness connector C0932 face view and pin numbers (Scheme 110) For EAT ECU input/output information see EAT ECU CONNECTOR C0932 PIN DETAILS table.

EAT ECU CONNECTOR C0932 PIN DETAILS

Scheme 110

MAIN RELAY

The main relay is located in the engine compartment fusebox and supplies battery voltage to the EAT ECU, in addition to other vehicle components. The main relay is energized by the ECM when the ignition is switched on.

When the ignition is switched off, the ECM will maintain the main relay in an energized state for several minutes. This allows for cooling fan operation to continue after the engine has been switched off and allows other vehicle ECU's to remain active. The EAT ECU remains active for a short period after the ignition is switched off to allow EEPROM fault code data to be stored.

In the event of a main relay failure, any of the following symptoms may be observed

1. The gearbox will be locked in 4th gear (limp home mode).
2. No CAN communications will be available.

DIAGNOSTICS

A diagnostic socket allows the exchange of information between the EAT ECU and TestBook/T4. The diagnostic socket is located behind the center console, in the passenger footwell. (Scheme 111)

The diagnostic socket is connected to the EAT ECU on an ISO 9141 K Line. The system uses a "P" code diagnostic strategy and can record faults relating to gearbox operation. The codes can be retrieved using TestBook/T4 or any diagnostic tool using Keyword 2000 protocol.

Scheme 111

DIAGNOSTIC TROUBLE CODES (DTC)

The following table lists "P" codes, affected components and fault description. The diagnostics related to diagnostic trouble codes introduced by ECD3 are disabled on vehicles built prior to the ECD3 compliance date.

JATCO "P" CODE

Controller Area Network (CAN) Bus

The CAN bus is a high speed broadcast network between the ECM, instrument pack, ABS ECU and the EAT ECU allowing fast exchange of data between the ECU's every few microseconds.

The bus comprises two wires which are identified as CAN Low (L) and CAN High (H). The wires are twisted together to minimize the electromagnetic interference (noise) produced by the CAN messages.

To prevent message errors from electrical reflections, 120-ohm resistors are incorporated into the CAN wire terminals of the ECM, instrument pack, ABS ECU and the EAT ECU.

CAN messages consist of a signal which is simultaneously transmitted, in opposite phase, on both wires. CAN L switches between 2.5 and 1.5 volts, while CAN H switches between 2.5 and 3.5 volts. This causes a potential difference between the two lines to switch between 0 volt (logic 1) and 2 volts (logic 0) to produce the digital signal message. (Scheme 112)

In the event of a CAN bus failure any of the following symptoms may be observed

1. Transmission defaults to 4th gear.
2. Torque converter lock-up control is disabled.
3. Transmission of torque reduction message to the ECM is inhibited.

Scheme 112

EAT ECU CAN Messages

For CAN message inputs and outputs from and to the EAT ECU, see CAN MESSAGE INPUTS & OUTPUTS table.

CAN MESSAGE INPUTS & OUTPUTS

Actual Engine Torque

This message from the ECM indicates the actual engine torque produced at any one time. The EAT ECU uses this message to control gear shift scheduling.

Engine Coolant Temperature

This message from the ECM is used by the EAT ECU for OBD diagnostic functions and to detect when the engine has completed a WARM UP cycle.

Engine Friction

This message from the ECM is the current frictional torque losses within the engine and is expressed as a percentage of maximum engine torque. The EAT ECU uses this message to control gear shift scheduling.

Engine Speed

This message from the ECM is used by the EAT ECU to calculate gearbox oil pressure to assist control of gear shift scheduling.

Engine Speed Signal Error

This message from the ECM informs the EAT ECU if there is a fault with the engine speed calculation. If necessary, the EAT ECU then adjusts gearbox operation to prevent possibility of mechanical damage.

Engine Torque Error

This message from the ECM informs the EAT ECU that torque values received are incorrect and there is an ECM torque measurement error.

Estimated Engine Torque

This message from the ECM informs the EAT ECU of the level of torque that the engine is producing. The EAT ECU uses this message to control gearshift scheduling.

Ignition Switch Status

This message from the ECM is produced when the ECM energizes the main relay. The EAT ECU uses this message to initiate the power-down routine at ignition off.

This message from the ECM is the theoretical engine torque for current throttle setting and engine operating conditions. This is the same as the actual engine torque unless torque reduction in progress and is expressed as a percentage of maximum engine torque. The EAT ECU uses this message to control gear shift scheduling.

Throttle Angle

This message from the ECM informs the EAT ECU of the throttle angle (driver demand). The EAT ECU uses this message to control gear shift scheduling. l Torque reduction status. This message from the ECM informs the EAT ECU of the success of a torque reduction request.

Engine MIL Status

This message from the ECM indicates to the EAT ECU that the MIL has been illuminated by the ECM. The EAT ECU will disable OBD fault monitoring.

Hill Descent Activity Status

This message from the ABS ECU informs the EAT ECU that HDC has been requested. Providing the selector lever is in position 1 or R, the EAT ECU enters HDC mode and assists the ABS with engine braking.

Virtual Throttle Position (Diesel Only)

This message from the ECM informs the EAT ECU of a virtual throttle position when cruise control is enabled and operative. The message is compiled from a combination of main throttle and secondary throttle inputs.

Cooling Request

Request for additional cooling of the transmission fluid. The ECM switches on, or increases the speed of the cooling and, if fitted, condenser fans.

Current/Target Gear

Informs the ECM what gear is currently engaged or, if a gear shift is in progress, the gear to which the gearbox is shifting. Used by the ECM for engine load change prediction.

Gear Selector Lever Position

The EAT ECU transmits a signal to the ECM of the gear selector lever position selected by the driver. The ECM outputs a CAN message to the instrument pack to display the selection in the LCD.

Gear Shift In Progress

Informs the ECM when a gear shift is in progress. Used at idle speed to compensate for engine load changes during the gear shift.

Gearbox Fault Status

The EAT ECU uses this signal to display the status of the EAT ECU. If a gearbox fault occurs, the EAT ECU will generate this message to alternately display "F" and "4" in the instrument pack LCD and initiate the default strategy for the gearbox.

Torque Reduction Request

Requests the ECM to reduce engine torque for a gear shift (equivalent to lifting off the throttle in manual gearbox models). Amount of torque reduction required expressed as a percentage of maximum engine torque.

Gearbox MIL Status

The EAT ECU transmits a signal to the ECM that there is a gearbox fault which will increase emissions above an acceptable level. The ECM outputs a message to the instrument pack which illuminates the MIL.

Gear Shift Mode

This signal is used to display the currently selected gearshift mode, drive, sport or manual, in the instrument pack LCD. This signal is originated from the EAT ECU.

The EAT ECU controls the following functions

1. Gear shift scheduling.
2. Lock-up control.
3. Line pressure control.
4. Driving mode engagement.
5. Sport mode engagement.
6. Manual (CommandShift) mode engagement.
7. Reverse inhibit.
8. Hill mode strategy engagement.
9. Downhill recognition.
10. Cruise mode engagement.
11. Cooling strategy engagement.
12. Selector position display.
13. Driving mode display.
14. Fault status.
15. Fault code storage.
16. Emergency/Fail-safe program control.

GEAR SHIFT SCHEDULING

The EAT ECU uses the relationship between the vehicle speed and the throttle position to carry out gear shift scheduling. Depending on these inputs, the EAT ECU controls gear selection using the three shift solenoid valves located in the valve block.

LOCK-UP CONTROL

The EAT ECU monitors the relationship between vehicle speed and throttle position to calculate when to lock-up the torque converter.

Lock-up control is possible in 4th and 5th gears. For example, lock-up is possible at high speed cruising with low throttle position. Torque converter lock-up is also provided in 2nd and 3rd gears when high fluid temperatures are detected by the ECU.

A refinement to the torque converter lock-up system is the reduction of harshness or shock during torque converter lock-up.

The EAT ECU controls the lock-up solenoid valve to provide a smooth lock-up function. The solenoid is operated slowly, and gradually varies the fluid pressure to the lock-up control valve. This causes the lock-up clutch to engage slowly, producing a smooth operation.

To promote engine warm-up at low temperatures, the EAT ECU will inhibit lock-up if the gearbox fluid temperature is below 40°C (104°F).

LINE PRESSURE CONTROL

Line pressure refers to the operating fluid pressure that is supplied to the multi-plate clutches, multi-plate brakes and brake band within the gearbox.

Line pressure control provides smooth vehicle operation and gear shift action. The line pressure control is continuously responding to current driving conditions to regulate and deliver the optimum operating pressure at all times. For example, line pressure is lower under normal operating conditions than it would be under hard acceleration.

The EAT ECU controls line pressure by actuating the line pressure solenoid valve in the valve block. The ECU calculates the line pressure required by using engine speed, vehicle speed and throttle position.

High line pressures will cause very harsh gearshifts and gear engagement. Low line pressure will cause gearshifts to take an excessive amount of time to change, which will quickly burn out the clutches, brakes and brake band within the gearbox.

DRIVING MODES

There are five different driving modes that the driver can select

1. Normal mode.
2. Sport mode.
3. Manual (CommandShift) mode.
4. Hill Descent Control (HDC) mode
5. Cruise mode.

Normal, sport, cruise and HDC modes are selected manually by the driver. Fast off and stop go modes are controlled by the EAT ECU responding to driving conditions.

The different modes are selected by the gear selector lever or, in the case of cruise mode and HDC, a separate switch. The gear change scheduling is altered to correspond with the mode selected.

Normal Mode

On power up the EAT ECU always initializes normal mode. In this mode all automatic/adaptive modes are active. Normal mode uses gear shift and lock-up maps which allows vehicle operation which is a compromise between performance, fuel consumption and emissions.

Sport Mode

In sport mode the EAT ECU controls the gearbox to downshift more readily and use gear change schedules that hold the lower gears for longer at high engine speeds. This enhances acceleration and vehicle responsiveness. Sport mode is selected by moving the gear selector lever to the S/M position. SPORT is displayed in the instrument pack LCD when this mode is selected.

Manual (CommandShift) Mode

Manual mode allows the driver to operate the gearbox as a semi-automatic, CommandShift gearbox. The driver can change up and down the five gears with the freedom of a manual transmission.

Gearshift maps programmed in the EAT ECU protect the engine at high engine speeds by automatically changing up to prevent engine over speed and changing down to prevent stalling.

Manual mode is entered by moving the selector lever to the S/M position and then moving the lever to either the + or - positions to move the gearbox up and down the five gear ratios. Manual mode is exited by moving the selector back to position "D".

HDC Mode

The HDC mode assists the ABS in controlling the descent of the vehicle in either 1st gear ratio or reverse gear ratio. HDC mode is initiated by selecting 1 or R on the selector lever, depressing the HDC button adjacent to the selector lever and throttle pedal released (low demand position). The instrument pack illuminates the HDC warning lamp and the LCD will display the selected gear (1 or R).

The EAT ECU will maintain the selected gear ratio and apply engine braking to assist the ABS in controlling the vehicle's descent.

Cruise Mode

Cruise control is activated by depressing the cruise control switch in the center console. When cruise control is active, the EAT ECU senses this as a hardwired input from the cruise control ECU (non-NAS KV6 models) or interface unit (Td4 and NAS KV6 models). In cruise mode the EAT ECU uses a dedicated gearshift map to control the gearbox and assist in maintaining the set vehicle speed. The gearbox cruise mode is cancelled by applying the brake pedal or deselecting cruise control. Cruise mode is suspended when the throttle demand is increased and is reinstated when the pedal is released and the set speed resumed. Cruise mode is also suspended when the suspend switch on the steering wheel is pressed.

REVERSE INHIBIT

If the vehicle exceeds 6 mph (10 km/h) in the forward direction, and Reverse (R) gear is selected, the EAT ECU switches on the low clutch timing solenoid valve in the valve block, which drains the fluid from the reverse clutch.

This function prevents the gearbox from engaging reverse gear when the vehicle is moving in a forward direction, so preventing damage to the gearbox.

HILL MODE

Hill mode modifies the gearbox shift pattern to assist driveability on steep gradients. The EAT ECU detects the conditions to activate hill mode by monitoring the engine torque values, throttle angle and engine speed. This mode also assists driving at high altitudes and trailer towing.

DOWNHILL RECOGNITION

On downhill slopes there is a tendency for automatic gearboxes to upshift due to the increase in vehicle speed and the decrease in throttle angle.

The reduction in engine braking causes the driver to use the brakes. A downhill slope is recognized by EAT ECU as an increase in vehicle speed with the decrease in throttle angle.

When a downhill slope is recognized and the brakes are applied, the shift pattern is over-ruled and the gearbox shifts down a gear if engine speed allows. The downhill mode is cancelled upon application of the throttle.

COOLING STRATEGY

The purpose of the cooling strategy is to reduce engine and gearbox temperatures during high load conditions, for example when towing trailers. Under these conditions the engine and gearbox may generate excessive heat.

While in any gear other than 5th, or in 5th gear with the vehicle speed above 38 mph (61 km/h), if the gearbox fluid temperature increases to 127°C (260°F), the EAT ECU employs the cooling strategy.

This strategy consists of a separate shift and torque converter lock-up map that allows torque converter lock-up or gear changes to occur outside of their normal operating parameters.

This will reduce either the engine speed or the slip in the torque converter, therefore reducing the heat generated.

The EAT ECU cancels the cooling strategy when gearbox fluid temperature decreases to 120°C (248°F).

ENGINE COOLING FAN

If the gearbox fluid temperature increases to 110°C (230°F), the EAT ECU sends a cooling request message to the ECM on the CAN bus. The ECM then switches the engine cooling fan on, or if it is already on, keeps it on, to maintain the air flow through the fluid cooler.

The EAT ECU cancels the cooling request when the fluid temperature decreases to 100°C (212°F).

If the EAT ECU detects a failure in an associated component, a fault code will be stored in the EAT ECU memory. TestBook/T4 is used to retrieve these fault codes to identify the cause of the failure.

If the EAT ECU detects a fault with the gearbox system it will enter a fail safe mode. There are many fail safe modes the EAT ECU can adopt.

The EAT ECU will adopt the fail safe mode most acceptable for the driver and will ensure the least amount of damage to the gearbox.

When a fault is detected a CAN message is sent from the EAT ECU to the instrument pack and the MIL will be illuminated if the fault is related to OBD. If the ECU is able to implement a limp home mode, the instrument pack LCD will display "4" and "F" alternately as the gearbox status display. Some faults may not display "4" and "F" in the instrument pack, but the driver may notice a reduction in shift quality.

ENGINE SPEED & THROTTLE MONITORING

The ECM constantly supplies the EAT ECU with information on engine speed and throttle angle through messages on the CAN bus. This information is used by the EAT ECU to calculate the correct timing of gear changes.

If the messages are not received from the ECM, the EAT ECU will implement a back-up strategy to protect the gearbox from damage, while allowing the vehicle to be driven.

In the event of an engine speed signal failure any of the following symptoms may be observed

1. Decrease in fuel economy.
2. Increase in engine emissions.

In the event of a throttle position signal failure, any of the following symptoms may be observed

1. Harsh gear changes.
2. No kickdown.
3. Torque reduction request inhibited.

COMPONENT LOCATIONS

For component locations (Scheme 113)- (Scheme 116). For JATCO A/T gearbox control diagram (Scheme 117)

Scheme 113

Scheme 114

Scheme 115

Scheme 116

Scheme 117

INTRODUCTION

The JATCO JF506E automatic gearbox is an electronically controlled, five speed gearbox, which incorporates software to enable the gearbox to operate as a semi-automatic gearbox. The transmission, previously known as "Septronic" is designated "CommandShift" from 2003 MY.

The gearbox can be operated as a conventional automatic gearbox by selecting P, R, N, D, 4, 2 or 1 on the selector lever. Moving the selector mechanism across the gate to the S/M position sends a signal to the Transmission Control Module (TCM) and puts the gearbox into sport/manual mode.

In sport mode, the gearbox still operates as a conventional automatic transmission, but the unit becomes more responsive to driver demands. Lower gears will be held longer and the transmission will downshift more readily. This gives increased acceleration and improves vehicle response. When in sport mode, if the selector lever is moved to the + or - positions, the system will automatically change to operate in manual mode.

Manual gear changes can be performed sequentially using the selector lever. Movement of the selector lever in the forward (+) direction changes the gearbox up the ratios and movement in a rearward (-) direction changes the gearbox down the ratios.

The TCM and the Engine Control Module (ECM) control gearbox operation, which communicate via a Controller Area Network (CAN) Bus. The TCM receives information from the ECM and gearbox sensors to calculate the appropriate gear ratio for the conditions and controls solenoid valves to operate the gearbox as required.

Diagnostic Trouble Codes & Freeze Frames

When an OBD relevant transmission fault is detected the TCM stores a temporary (Pending) fault code in its memory. An OBD Scan Tool can read this temporary fault code using J1979 mode $07. The temporary fault code is retained until the associated fault counter reaches zero. At the first initialization of the TCM this counter is pre-loaded with a value of 10. The counter is decremented one count for each successful pass of all the diagnostic tests during a warm-up cycle.

If during the next driving cycle of the vehicle (this may be after any number of journeys if the diagnostic has not been executed) when the subsequent operation of the diagnostic test identifies the same fault, the following occurs

1. The temporary diagnostic trouble code (DTC) becomes a permanent code and the TCM transmits this DTC code as the response to OBD diagnostic mode $03 and MIL illumination is requested. The ECM stores a generic transmission failure P code and a data freeze frame. This freeze frame can be requested from the ECM using the scan tool J1979 mode $02 request. On this request the TCM will send a positive response, but the data will equal $00 (i.e. No Parameter Identifiers - PIDs are supported). Upon ignition off this permanent code is stored in the TCM memory and the pending DTC code is erased.
2. If the subsequent and consecutive 3 complete driving cycles (in which the diagnostic test for the fault is completed) are clear of the fault at ignition off, then the MIL ON request is turned off.
3. If the subsequent and consecutive 40 warm-up cycles (in which the diagnostic test for the fault is also completed) are clear, then the permanent code (DTC) is erased from the TCM memory.
4. All permanent and temporary faults can be cleared from the TCM memory using the scan tool J1979 mode $04 request.
5. All current transmission diagnostic data will be returned to a scan tool J1979 mode $01.
6. All transmission vehicle information will be returned to a J1979 mode $09 request.

Inputs & Outputs

For input and output signal description, see INPUT & OUTPUT SIGNALS table.

INPUT & OUTPUT SIGNALS

TRANSMISSION CONTROL MODULE

The Transmission Control Module (TCM) performs four self-test integrity diagnostics on its internal hardware and software to check for faults. A fault is detected if

1. The diagnostic drive cycle is active and an electrical fault of the ground return line has been detected.
2. The engine speed is greater than 420 RPM, the diagnostic drive cycle is active and the supply voltage is greater than 18 volts or less than 8 volts.
3. The calculated checksum does not match the stored checksum.
4. The diagnostic drive cycle is active and the incorrect calibration file has been selected.

If the table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 118)

Scheme 118

CONTROLLER AREA NETWORK (CAN)

The Transmission Control Module (TCM) is a CAN based control module. It can communicate directly with all the other CAN users, those being the traction control unit, the ECM and the instrument pack. In addition to vehicle data (i.e. data about vehicle conditions, e.g. engine speed) the network carries data specifically for error checking of the vehicle data messages. The TCM uses this data to confirm that the communications network is functioning correctly.

The TCM forms a bi-directional terminated node on a twisted pair ring bus configuration. This configuration requires all CAN users to be connected at all times, as each unit completes the ring. The TCM will not operate correctly without CAN present. If messages that are expected by the TCM are not being received (all modules transmit some data on a regular basis) or messages are proven to be repeatedly corrupt, the TCM will register an appropriate network failure. If the failure is identified on two consecutive drive cycles then the appropriate DTC is logged.

If the table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 119)

Scheme 119

Description

The gearbox uses nine solenoid valves located on the valve block. The solenoid valves are energized/de-energized by the TCM to control the gearbox fluid flow around the gearbox to supply clutches, brakes and brake band (gear change scheduling), fluid to the torque converter, lubrication and cooling.

The TCM controls each solenoid valve separately. All nine solenoid valves can be classified into two types by their operating mode. Three of them are duty solenoid valves and the remaining six are on-off solenoid valves.

Each solenoid valve consists of an internal coil and needle valve. A voltage is passed through the coil of the solenoid to actuate the needle valve. The needle valve opens and closes the fluid pressure circuits.

On-off solenoid valves close the fluid pressure circuits in response to current flow. Duty solenoid valves repeatedly turn on and off in 50 Hz cycles. This opens and closes the fluid circuits allowing a higher level of control on the circuits. For example, smooth operation of the lock-up clutch in the torque converter to eliminate harsh engagement/disengagement. The TCM supplies all of the solenoid valves with battery voltage and an earth path.

The On/Off solenoid valves are

1. Shift solenoid valve A.
2. Shift solenoid valve B.
3. Shift solenoid valve C.
4. Low clutch timing solenoid valve.
5. Reduction timing solenoid valve.
6. 2nd - 4th gear brake timing solenoid valve.

The TCM switches the On/Off solenoid valves to open and close in response to vehicle speed and throttle opening. Shift solenoid valves A, B and C are used to engage the different gear ratios within the gearbox. The position of these solenoid valves at any one time determines the gear selected.

The duty solenoid valves are

1. Torque converter clutch (TCC) solenoid valve.
2. Line pressure control solenoid valve.
3. 2nd - 4th gear duty brake solenoid valve.

The torque converter clutch solenoid valve is used by the TCM to control the lock-up of the torque converter depending upon the vehicle speed and throttle position. The TCM will actuate the TCC solenoid valve, which operates the torque converter clutch control valve to direct fluid to either lock or unlock the torque converter.

The line pressure control solenoid valve and 2nd - 4th gear duty brake solenoid valve are used by the TCM to control fluid line pressure in the gearbox. The TCM calculates the line pressure by using the engine speed, vehicle speed and throttle angle. The TCM then actuates the solenoid valves accordingly to achieve the required line pressure.

Solenoid Valve Diagnostic Checks

There are two diagnostic checks for each solenoid valve. A fault is detected if

1. The diagnostic drive cycle is active and a solenoid short to B+ condition has been detected.
2. The diagnostic drive cycle is active and a solenoid short to ground or an open circuit condition has been detected.

If the table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 120)

Scheme 120

TRANSMISSION RANGE SENSOR (PRND421)

There are seven sets of contacts in the selector and inhibitor switch, which are operated by the selector shaft. Each set of contacts corresponds to one of the seven selector lever positions (PRND421). Only one set of contacts will supply battery voltage to the TCM and the light emitting diode (LED) module at any one time. The TCM monitors the switch outputs every 10 ms.

A pair of contacts are also provided for the crank inhibit circuit. The contacts are only closed when the selector lever is in the "P" and "N" positions.

There are two diagnostic checks of the transmission range sensor, a fault is detected if

1. The vehicle speed is greater than 6.2 mph, the throttle angle is greater than 12.5 %, the diagnostic drive cycle is active and no signal has been received from the transmission range sensor.
2. The diagnostic drive cycle is active, the vehicle speed is greater than 6.2 mph, the throttle angle is greater than 12.5 % and the transmission range sensor has indicated multiple gear positions at the same time.

If the table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 121)

Scheme 121

GEAR RATIO FUNCTIONAL CHECK

The TCM monitors the speed sensors that are located at input and output gear positions, internal to the transmission. These ratios describe the gear selected. A Comparison of these speed sensors against the gear selected indicates a fault is present.

If the table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 122)

Scheme 122

TRANSMISSION FLUID TEMPERATURE SENSOR

The TCM uses this sensor to monitor the gearbox fluid temperature. When the fluid is cold, the TCM changes gear at higher engine speeds to promote faster fluid warm-up. If the fluid temperature becomes too high, the TCM transmits a cooling request on the CAN link to the ECM to operate the cooling fans.

The fluid temperature sensor is a negative temperature coefficient sensor. As the temperature rises, the resistance in the sensor decreases. As temperature decreases, the resistance in the sensor increases and the output voltage to the TCM changes in proportion. The output voltage from the sensor is in the range of 0-2.5 Volts with the lower voltage representing the highest temperature. The change in resistance is proportional to the temperature of the gearbox fluid. From the resistance of the sensor, the TCM calculates the temperature of the gearbox fluid. Should the fluid temperature sensor fail the TCM uses ECM engine coolant temperature; if the engine coolant temperature fails a fixed value is used.

The diagnostic changed between 2002MY and 2003MY. At 2002MY a fault was identified if the sensor exceeded the minimum or maximum threshold value identified in the table below for a time of 180 seconds. At 2003MY and beyond a fault is identified if the sensor remained within the threshold values identified in the table for the given period.

If the table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 123)or (Scheme 124).

Scheme 123

Scheme 124

TORQUE CONVERTER CLUTCH

In a torque converter there is always a certain amount of slip between the impeller and turbine. This will contribute to a reduction in fuel economy especially during high speed cruising. This is eliminated by the torque converter lock-up mechanism. The lock-up mechanism is attached to the turbine and controls a lock-up clutch, which is integral with the torque converter. The lock-up mechanism comprises of a torque converter solenoid valve, a torque converter control valve and a torque converter clutch. The lock-up control is provided by the TCM, which operates the torque converter solenoid valve. The TCM controls the clutch engagement and release according to the lock-up schedule programmed into the control module and the vehicle speed and throttle angle.

The performance of the clutch is monitored. If the level of slip detected when the clutch is locked exceeds a vehicle speed dependent threshold then an error is detected.

If the table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 125)

Scheme 125

TURBINE SHAFT SPEED SENSOR

The turbine shaft speed sensor is located within the gearbox and is used by the TCM to monitor the input shaft speed. The TCM uses this sensor to ensure the correct gear ratio is selected and to ensure that there is not excessive slip within the gearbox drive train. The turbine shaft speed sensor detects the input shaft speed (turbine speed) and sends an electrical output to the TCM, which also supplies a ground path for the sensor. The sensor is an inductive sensor that produces a sinusoidal output at a frequency of 36 pulses per revolution of the input shaft.

If the vehicle speed exceeds 25 mph and the engine speed is above 1500 RPM while the turbine revolution is less than 600 RPM, after a period of 2 seconds a Turbine Failure is detected.

If the table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 126)

Scheme 126

OUTPUT SHAFT SPEED SENSOR

The vehicle speed sensor is located within the gearbox. The TCM uses this sensor to monitor the rotational speed of the parking gear and to translate this reading into a vehicle speed. The TCM also monitors the vehicle speed using a signal from the ABS Control Module (CM). The vehicle speed sensor detects the parking gear rotation speed and sends an electrical output to the TCM, which also provides an earth path for the sensor. The sensor is an inductive sensor that produces a sinusoidal output at a frequency of 18 pulses per revolution of the parking gear. The TCM calculates the equivalent vehicle speed based on the current selected gear ratio, the turbine speed sensor frequency and the intermediate speed sensor frequency, in comparison with the measured vehicle speed sensor frequency to determine correct operation. In the event of a discrepancy the TCM uses a calculated vehicle speed based on the remaining functional speed sensors.

At 2004MY the intermediate shaft speed sensor was deleted, therefore from 2004MY onwards the output shaft speed sensor diagnostic is now based on vehicle speed.

In both instances a rationality test is used to detect a fault condition. A fault is present if a minimum or maximum shaft speed threshold (up to 2003MY) or vehicle speed threshold (2004MY Onwards) is exceeded.

If the appropriate table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 127)or (Scheme 128).

Scheme 127

Scheme 128

INTERMEDIATE SHAFT SPEED SENSOR - UP TO 2004MY

The intermediate shaft speed sensor is located within the gearbox. The TCM uses this sensor to ensure correct gear engagement and to monitor the amount of slip within the gearbox. The TCM calculates the slip within the gearbox by comparing the difference between the inputs from the intermediate shaft speed sensor and the turbine shaft speed sensor. The intermediate shaft speed sensor detects the output gear rotation speed and sends an electrical output to the TCM, which also supplies an earth path for the sensor. The sensor is an inductive sensor that produces a sinusoidal output at a frequency of 54 pulses per revolution of the output gear. A rationality test is used to detect a fault condition. A fault is present if the intermediate shaft speed is less than 400 RPM, while the enabling conditions are satisfied.

If the table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. (Scheme 129)

Scheme 129

DIAGNOSTIC TESTS

Note. For circuit identification during testing, see WIRING DIAGRAMS .

Possible Causes

1. Open Circuit C932/17(SB) to C243/18(SB). See step 1 under CHECK.
2. Short Circuit C243/18(SB) to Battery. See step 2 under CHECK.
3. Open Circuit C932/9(B) to Ground C553/6(B). See step 3 under CHECK.
4. Open Circuit C932/38(B) to Ground C553/4(B). See step 4 under CHECK.
5. Connectors C243, C553 and C932. See step 5 under CHECK.
6. JATCO ATCU ECU. See step 6 under CHECK.

Check

1. OPEN_CIRCUIT Open Circuit C932/17(SB) to C243/18(SB). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/18(SB) to Battery. Check resistance < 5.0 ohm.
3. OPEN_CIRCUIT Open Circuit C932/9(B) to Ground C553/6(B). Check resistance > 1 megohm.
4. OPEN_CIRCUIT Open Circuit C932/38(B) to Ground C553/4(B). Check resistance > 1 megohm.
5. CONNECTOR Connectors C243, C553 and C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
6. JATCO ATCU ECU No detail available for this fault.

1. Passenger fuse box Fuse 35. See step 1 under CHECK.
2. Open Circuit C580/3(W) to C244/10(W). See step 2 under CHECK.
3. Open Circuit C244/6(W) to C059/3(W). See step 3 under CHECK.
4. Short Circuit C244/6(W) to Ground. See step 4 under CHECK.
5. Open Circuit C244/5(GY) to C932/8(GY). See step 5 under CHECK.
6. Open Circuit C244/3(OB) to C932/7(OB). See step 6 under CHECK.
7. Open Circuit C244/4(RG) to C932/45(RG). See step 7 under CHECK.
8. Open Circuit C244/1(WB) to C932/27(WB). See step 8 under CHECK.
9. Open Circuit C244/2(WU) to C932/25(WU). See step 9 under CHECK.
10. Open Circuit C244/7(NG) to C932/26(NG). See step 10 under CHECK.
11. Open Circuit C244/9(KO) to C932/30(KO). See step 11 under CHECK.
12. Short Circuits C244 pins 1, 2, 3, 4, 5, 7 and 9. See step 12 under CHECK.
13. Open Circuit C244/8(NK) to 12V. See step 13 under CHECK.
14. Connectors C059, C244, C245, C580. See step 14 under CHECK.
15. Bowden (gear selector) cable out of adjustment. See step 15 under CHECK.
16. Gear selector switch mechanism. See step 16 under CHECK.
17. Immobilizer EWS3 ECU. See step 17 under CHECK.
18. JATCO ATCU ECU. See step 18 under CHECK.

1. POWER_DISTRIBUTION Passenger fuse box Fuse 35. Check for fuse not correctly inserted, fuse blown, fuse connections loose, damaged or corroded. Certain diagnostics may also perform further checks to try and narrow down the fault. E.g. Check if other circuits fed by the same fuse are also experiencing problems.
2. OPEN_CIRCUIT Open Circuit C580/3(W) to C244/10(W). Check resistance > 1 megohm.
3. OPEN_CIRCUIT Open Circuit C244/6(W) to C059/3(W). Check resistance > 1 megohm.
4. SHORT_CIRCUIT Short Circuit C244/6(W) to Ground. Check resistance < 5.0 ohm.
5. OPEN_CIRCUIT Open Circuit C244/5(GY) to C932/8(GY). Check resistance > 1 megohm.
6. OPEN_CIRCUIT Open Circuit C244/3(OB) to C932/7(OB). Check resistance > 1 megohm.
7. OPEN_CIRCUIT Open Circuit C244/4(RG) to C932/45(RG). Check resistance > 1 megohm.
8. OPEN_CIRCUIT Open Circuit C244/1(WB) to C932/27(WB). Check resistance > 1 megohm.
9. OPEN_CIRCUIT Open Circuit C244/2(WU) to C932/25(WU). Check resistance > 1 megohm.
10. OPEN_CIRCUIT Open Circuit C244/7(NG) to C932/26(NG). Check resistance > 1 megohm.
11. OPEN_CIRCUIT Open Circuit C244/9(KO) to C932/30(KO). Check resistance > 1 megohm.
12. SHORT_CIRCUIT Short Circuits C244 pins 1, 2, 3, 4, 5, 7 and 9. Check resistance < 5.0 ohm.
13. OPEN_CIRCUIT Open Circuit C244/8(NK) to 12V. Check resistance > 1 megohm.
14. CONNECTOR Connectors C059, C244, C245, C580. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
15. Bowden Cable Out Of Adjustment This fault is generated if there is a fault with the inhibitor switch or the gear selector switches. The engine can only be started if the Immobilization ECU (EWS3) has a 12V supply from the Inhibitor switch. This supply is derived from passenger fusebox fuse 35. The Inhibitor switch is linked to the gear lever, via a Bowden cable, and is integral with the Gear Selector switches. The inhibitor switch is an integral part of the gear selector switch mechanism and should close when either Neutral or Park is selected. This then supplies 12V to the Immobilization ECU, (EWS3) which allows the engine to be started. This fault is also generated if the selector switch shows no selection, or more than one selection. The gear selection indicator lamps, by the gear lever, are driven directly by the selector switch. The switch is located on top of the transmission and is operated by the gear lever via a steel Bowden cable. Ensure that this cable is adjusted correctly.
16. Gear Selector Switch Mechanism This fault is generated if there is a fault with the inhibitor switch or the gear selector switches. The engine can only be started if the Immobilization ECU (EWS3) has a 12V supply from the Inhibitor switch. This supply is derived from passenger fusebox fuse 35. The Inhibitor switch is linked to the gear lever, via a Bowden cable, and is integral with the Gear Selector switches. The inhibitor switch is an integral part of the gear selector switch mechanism and should close when either Neutral or Park is selected. This then supplies 12V to the Immobilization ECU, (EWS3) which allows the engine to be started. This fault is also generated if the selector switch shows no selection, or more than one selection. The gear selection indicator lamps, by the gear lever, are driven directly by the selector switch. The switch is located on top of the transmission and is operated by the gear lever via a steel Bowden cable. Ensure that this cable is adjusted correctly.
17. Immobilizer EWS3 ECU This fault is generated if there is a fault with the inhibitor switch or the gear selector switches. The engine can only be started if the Immobilization ECU (EWS3) has a 12V supply from the Inhibitor switch. This supply is derived from passenger fusebox fuse 35. The Inhibitor switch is linked to the gear lever, via a Bowden cable, and is integral with the Gear Selector switches. Ensure that C059/3 switches between 12V and ground when the gear selector is moved from Neutral or Park to Drive and that the connector is sound. If Textbook/T4 available, use the Basic Toolbox and diagnostics for the EWS3 ECU to investigate this fault in more detail.
18. JATCO ATCU ECU This fault is generated if there is a fault with the inhibitor switch or the gear selector switches. The engine can only be started if the Immobilization ECU (EWS3) has a 12V supply from the Inhibitor switch. This supply is derived from passenger fusebox fuse 35. The Inhibitor switch is linked to the gear lever, via a Bowden cable, and is integral with the Gear Selector switches. Test the operation of the gear selector mechanism using Real Time Display and also check the gear position shown by the lamps by the gear lever. Fully investigate all other possibilities before replacing the JATCO ECU.

1. Open Circuit C243/7(WK) to C932/39(WK). See step 1 under CHECK.
2. Open Circuit C243/8(KB) to C932/20(KB). See step 2 under CHECK.
3. Short Circuit C243/7(WK) to Ground or Battery. See step 3 under CHECK.
4. Short Circuit C243/8(KB) to Ground or Battery. See step 4 under CHECK.
5. Connectors C243,C932. See step 5 under CHECK.
6. ATF temperature sensor. See step 6 under CHECK.
7. JATCO ATCU ECU. See step 7 under CHECK.

1. OPEN_CIRCUIT Open Circuit C243/7(WK) to C932/39(WK). Check resistance > 1 megohm.
2. OPEN_CIRCUIT Open Circuit C243/8(KB) to C932/20(KB). Check resistance > 1 megohm.
3. SHORT_CIRCUIT Short Circuit C243/7(WK) to Ground or Battery. Check resistance < 5.0 ohm.
4. SHORT_CIRCUIT Short Circuit C243/8(KB) to Ground or Battery. Check resistance < 5.0 ohm.
5. CONNECTOR Connectors C243, C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
6. ATF Temperature Sensor If the vehicle speed exceeds 12 mph (20 kph) while the ATF temperature sensor reads less than -22°F (-30°C) then a ATF TEMPERATURE SENSOR FAILURE fault is reported.
7. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit C243/2(R) to C932/24(R). See step 1 under CHECK.
2. Open Circuit C243/1(U) to C932/20(KB). See step 2 under CHECK.
3. Short Circuit C243/2(R) to Ground or Battery. See step 3 under CHECK.
4. Short Circuit C243/1(U) to Ground or Battery. See step 4 under CHECK.
5. Connectors C243, C932. See step 5 under CHECK.
6. Turbine speed sensor. See step 6 under CHECK.
7. JATCO ATCU ECU. See step 7 under CHECK.

1. OPEN_CIRCUIT Open Circuit C243/2(R) to C932/24(R). Check resistance > 1 megohm.
2. OPEN_CIRCUIT Open Circuit C243/1(U) to C932/20(KB). Check resistance > 1 megohm.
3. SHORT_CIRCUIT Short Circuit C243/2(R) to Ground or Battery. Check resistance < 5.0 ohm.
4. SHORT_CIRCUIT Short Circuit C243/1(U) to Ground or Battery. Check resistance < 5.0 ohm.
5. CONNECTOR Connectors C243, C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
6. Turbine Speed Sensor If the vehicle speed exceeds 25 mph (40 kph) and the engine speed is above 1500 RPM while the turbine speed reads less than 600 RPM then, after a period of two seconds, a TURBINE SENSOR FAILURE fault is reported.
7. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit C243/6(U) to C932/5(U). See step 1 under CHECK.
2. Open Circuit C243/5(W) to C932/20(KB). See step 2 under CHECK.
3. Short Circuit C243/6(U) to Ground or Battery. See step 3 under CHECK.
4. Short Circuit C243/5(W) to Ground or Battery. See step 4 under CHECK.
5. Connectors C243, C932. See step 5 under CHECK.
6. Vehicle speed sensor. See step 6 under CHECK.
7. JATCO ATCU ECU. See step 7 under CHECK.

1. OPEN_CIRCUIT Open Circuit C243/6(U) to C932/5(U). Check resistance > 1 megohm.
2. OPEN_CIRCUIT Open Circuit C243/5(W) to C932/20(KB). Check resistance > 1 megohm.
3. SHORT_CIRCUIT Short Circuit C243/6(U) to Ground or Battery. Check resistance < 5.0 ohm.
4. SHORT_CIRCUIT Short Circuit C243/5(W) to Ground or Battery. Check resistance < 5.0 ohm.
5. CONNECTOR Connectors C243, C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
6. Vehicle Speed Sensor No detail available for this fault.
7. JATCO ATCU ECU No detail available for this fault.

1. Mechanical problem within gearbox. See step 1 under CHECK.

1. Mechanical Problem Within Gearbox Mechanical failure, physical inspection required.

1. Mechanical problem within gearbox. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. Mechanical Problem Within Gearbox No detail available for this fault.
2. JATCO ATCU ECU No detail available for this fault.

1. Mechanical problem within gearbox. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. Mechanical Problem Within Gearbox No detail available for this fault.
2. JATCO ATCU ECU No detail available for this fault.

1. Mechanical problem within gearbox. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. Mechanical Problem Within Gearbox No detail available for this fault.
2. JATCO ATCU ECU No detail available for this fault.

1. Mechanical problem within gearbox. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. Mechanical Problem Within Gearbox No detail available for this fault.
2. JATCO ATCU ECU No detail available for this fault.

1. Mechanical problem within gearbox. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. Mechanical Problem Within Gearbox No detail available for this fault.
2. JATCO ATCU ECU No detail available for this fault.

1. Mechanical problem within gearbox. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. Mechanical Problem Within Gearbox No detail available for this fault.
2. JATCO ATCU ECU No detail available for this fault.

1. Mechanical problem within gearbox. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. Mechanical Problem Within Gearbox No detail available for this fault.
2. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit C932/16(U) to C243/17(U). See step 1 under CHECK.
2. Short Circuit C243/17(U) to Battery. See step 2 under CHECK.
3. Short Circuit C243/17(U) to Ground. See step 3 under CHECK.
4. Connectors C243 and C932. See step 4 under CHECK.
5. Lock-up Duty solenoid. See step 5 under CHECK.
6. JATCO ATCU ECU. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932/16(U) to C243/17(U). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/17(U) to Battery. Check resistance < 5.0 ohm.
3. SHORT_CIRCUIT Short Circuit C243/17(U) to Ground. Check resistance < 5.0 ohm.
4. CONNECTOR Connectors C243 and C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
5. Lock-Up Duty Solenoid No detail available for this fault.
6. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit C932/18(Y) to C243/15(Y). See step 1 under CHECK.
2. Short Circuit C243/15(Y) to Battery. See step 2 under CHECK.
3. Short Circuit C243/15(Y) to Ground. See step 3 under CHECK.
4. Connectors C243 and C932. See step 4 under CHECK.
5. PL (Line Pressure) Duty solenoid. See step 5 under CHECK.
6. JATCO ATCU ECU. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932/18(Y) to C243/15(Y). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/15(Y) to Battery. Check resistance < 5.0 ohm.
3. SHORT_CIRCUIT Short Circuit C243/15(Y) to Ground. Check resistance < 5.0 ohm.
4. CONNECTOR Connectors C243 and C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
5. PL (Line Pressure) Duty Solenoid No detail available for this fault.
6. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit C932/15(R) to C243/9(R). See step 1 under CHECK.
2. Short Circuit C243/9(R) to Battery. See step 2 under CHECK.
3. Short Circuit C243/9(R) to Ground. See step 3 under CHECK.
4. Connectors C243 and C932. See step 4 under CHECK.
5. "A" Shift solenoid. See step 5 under CHECK.
6. JATCO ATCU ECU. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932/15(R) to C243/9(R). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/9(R) to Battery. Check resistance < 5.0 ohm.
3. SHORT_CIRCUIT Short Circuit C243/9(R) to Ground. Check resistance < 5.0 ohm.
4. CONNECTOR Connectors C243 and C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
5. "A" Shift Solenoid No detail available for this fault.
6. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit C932/14(O) to C243/10(O). See step 1 under CHECK.
2. Short Circuit C243/10(O) to Battery. See step 2 under CHECK.
3. Short Circuit C243/10(O) to Ground. See step 3 under CHECK.
4. Connectors C243 and C932. See step 4 under CHECK.
5. "B" Shift Solenoid. See step 5 under CHECK.
6. JATCO ATCU ECU. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932/14(O) to C243/10(O). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/10(O) to Battery. Check resistance < 5.0 ohm.
3. SHORT_CIRCUIT Short Circuit C243/10(O) to Ground. Check resistance < 5.0 ohm.
4. CONNECTOR Connectors C243 and C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
5. "B" Shift Solenoid No detail available for this fault.
6. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit C932/52(OU) to C243/11(OU). See step 1 under CHECK
2. Short Circuit C243/11(OU) to Battery. See step 2 under CHECK
3. Short Circuit C243/11(OU) to Ground. See step 3 under CHECK
4. Connectors C243 and C932. See step 4 under CHECK
5. "C" Shift solenoid. See step 5 under CHECK
6. JATCO ATCU ECU. See step 6 under CHECK

1. OPEN_CIRCUIT Open Circuit C932/52(OU) to C243/11(OU). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/11(OU) to Battery. Check resistance < 5.0 ohm.
3. SHORT_CIRCUIT Short Circuit C243/11(OU) to Ground. Check resistance < 5.0 ohm.
4. CONNECTOR Connectors C243 and C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
5. "C" Shift Solenoid No detail available for this fault.
6. JATCO ATCU ECU No detail available for this fault.

1. False Fault Detection - Mode switch not fitted. See step 1 under CHECK.

1. OPEN_CIRCUIT False Fault Detection, mode switch not fitted. Check resistance > 1 megohm.

1. 12V supply out of range. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. VOLTAGE_12 12V supply out of range. Check voltage 10.0-14.0 volts.
2. JATCO ATCU ECU No detail available for this fault.

DTC P1602 - Transmission Calibration - Selection Incorrect/Invalid

No detail available for this fault.

1. Internal ATCU ECU EEPROM fault. See step 1 under CHECK.

1. Internal ATCU ECU EEPROM Fault The JATCO ECU has reported a failure with its internal reprogrammable memory. This fault may have been caused by re-programming the ECU at a high temperature. Ensure that the ECU has cooled to ambient temperature and, if Textbook/T4 available, re-program the unit as described under VEHICLE MAINTENANCE, ECU CHECKS & RENEWAL. If this does not cure the problem, the ECU is probably faulty.

1. Open Circuit C243/4(R) to C932/21(R). See step 1 under CHECK.
2. Open Circuit C243/3(B) to C932/20(KB). See step 2 under CHECK.
3. Short Circuit C243/4(R) to Ground or Battery. See step 3 under CHECK.
4. Short Circuit C243/3(B) to Ground or Battery. See step 4 under CHECK.
5. Connectors C243, C932. See step 5 under CHECK.
6. Intermediate speed sensor. See step 6 under CHECK.
7. JATCO ATCU ECU. See step 7 under CHECK.

1. OPEN_CIRCUIT Open Circuit C243/4(R) to C932/21(R). Check resistance > 1 megohm.
2. OPEN_CIRCUIT Open Circuit C243/3(B) to C932/20(KB). Check resistance > 1 megohm.
3. SHORT_CIRCUIT Short Circuit C243/4(R) to Ground or Battery. Check resistance < 5.0 ohm.
4. SHORT_CIRCUIT Short Circuit C243/3(B) to Ground or Battery. Check resistance < 5.0 ohm.
5. CONNECTOR Connectors C243, C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
6. Intermediate Speed Sensor If the vehicle speed exceeds 25 mph (40 kph) while the Intermediate sensor reads less than 600 RPM then, after a period of two seconds, an INTERMEDIATE SENSOR FAILURE fault is reported.
7. JATCO ATCU ECU No detail available for this fault.

DTC P1717 - Low Clutch Timing Solenoid Out Of Range

No detail available for this fault.

DTC P1718 - Reduction Timing Solenoid Out Of Range

No detail available for this fault.

DTC P1719 - 2/4 Brake Timing Solenoid Out Of Range

No detail available for this fault.

1. Open Circuit C932/3(GP) to C243/16(GP). See step 1 under CHECK.
2. Short Circuit C243/18(GP) to Battery. See step 2 under CHECK.
3. Short Circuit C243/18(GP) to Ground. See step 3 under CHECK.
4. Connectors C243 and C932. See step 4 under CHECK.
5. 2/4 Brake Duty solenoid. See step 5 under CHECK.
6. JATCO ATCU ECU. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932/3(GP) to C243/16(GP). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/18(GP) to Battery. Check resistance < 5.0 ohm.
3. SHORT_CIRCUIT Short Circuit C243/18(GP) to Ground. Check resistance < 5.0 ohm.
4. CONNECTOR Connectors C243 And C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
5. 2/4 Brake Duty Solenoid No detail available for this fault.
6. JATCO ATCU ECU No detail available for this fault.

DTC P1776 - TCM Torque Down Request To ECM Out Of Range

No detail available for this fault.

1. Open Circuit C932/53(K) to C243/12(K). See step 1 under CHECK.
2. Short Circuit C243/12(K) to Battery. See step 2 under CHECK.
3. Short Circuit C243/12(K) to Ground. See step 3 under CHECK.
4. Connectors C243 and C932. See step 4 under CHECK.
5. Clutch timing solenoid. See step 5 under CHECK.
6. JATCO ATCU ECU. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932/53(K) to C243/12(K). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/12(K) to Battery. Check resistance < 5.0 ohm.
3. SHORT_CIRCUIT Short Circuit C243/12(K) to Ground. Check resistance < 5.0 ohm.
4. CONNECTOR Connectors C243 and C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
5. Clutch Timing Solenoid No detail available for this fault.
6. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit C932/10(OG) to C243/14(OG). See step 1 under CHECK.
2. Short Circuit C243/14(OG) to Battery. See step 2 under CHECK.
3. Short Circuit C243/14(OG) to Ground. See step 3 under CHECK.
4. Connectors C243 and C932. See step 4 under CHECK.
5. RDCN timing solenoid. See step 5 under CHECK.
6. JATCO ATCU ECU. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932/10(OG) to C243/14(OG). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/14(OG) to Battery. Check resistance < 5.0 ohm.
3. SHORT_CIRCUIT Short Circuit C243/14(OG) to Ground. Check resistance < 5.0 ohm.
4. CONNECTOR Connectors C243 and C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
5. RDCN Timing Solenoid No detail available for this fault.
6. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit C932/4(GR) to C243/13(GR). See step 1 under CHECK.
2. Short Circuit C243/13(GR) to Battery. See step 2 under CHECK.
3. Short Circuit C243/13(GR) to Ground. See step 3 under CHECK.
4. Connectors C243 and C932. See step 4 under CHECK.
5. 2/4 Brake timing solenoid. See step 5 under CHECK.
6. JATCO ATCU ECU. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932/4(GR) to C243/13(GR). Check resistance > 1 megohm.
2. SHORT_CIRCUIT Short Circuit C243/13(GR) to Battery. Check resistance < 5.0 ohm.
3. SHORT_CIRCUIT Short Circuit C243/13(GR) to Ground. Check resistance < 5.0 ohm.
4. CONNECTOR Connectors C243 and C932. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
5. 2/4 Brake Timing Solenoid No detail available for this fault.
6. JATCO ATCU ECU No detail available for this fault.

1. No Supply at switches C410/1(NK). See step 1 under CHECK.
2. Open Circuit C410/1(NK) to C575/8(NK). See step 2 under CHECK.
3. Open Circuit C410/4(LGK) to C932/41(LGK). See step 3 under CHECK.
4. Open Circuit C410/3(GB) to C932/19(GB). See step 4 under CHECK.
5. Open Circuit C410/2(GK) - to C932/37(GK). See step 5 under CHECK.
6. Short Circuit C932/41(LGK) to Ground or Battery. See step 6 under CHECK.
7. Short Circuit C932/19(GB) to Ground or Battery. See step 7 under CHECK.
8. Short Circuit C932/37(GK) to Ground or Battery. See step 8 under CHECK.
9. Multiple short circuits C932 pins 19, 37 and 41. See step 9 under CHECK.
10. Connectors C932, C410. See step 10 under CHECK.
11. Selector switch. See step 11 under CHECK.
12. JATCO ATCU ECU. See step 12 under CHECK.

1. VOLTAGE_12 No Supply at switches C410/1(NK). Check voltage 10.0-14.0 volts.
2. OPEN_CIRCUIT Open Circuit C410/1(NK) to C575/8(NK). Check resistance > 1 megohm.
3. OPEN_CIRCUIT Open Circuit C410/4(LGK) to C932/41(LGK). Check resistance > 1 megohm.
4. OPEN_CIRCUIT Open Circuit C410/3(GB) to C932/19(GB). Check resistance > 1 megohm.
5. OPEN_CIRCUIT Open Circuit C410/2(GK) - to C932/37(GK). Check resistance > 1 megohm.
6. SHORT_CIRCUIT Short Circuit C932/41(LGK) to Ground or Battery. Check resistance < 5.0 ohm.
7. SHORT_CIRCUIT Short Circuit C932/19(GB) to Ground or Battery. Check resistance < 5.0 ohm.
8. SHORT_CIRCUIT Short Circuit C932/37(GK) to Ground or Battery. Check resistance < 5.0 ohm.
9. SHORT_CIRCUIT Multiple short circuits C932 pins 19, 37 and 41. Check resistance < 5.0 ohm.
10. CONNECTOR Connectors C932, C410. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
11. Selector Switch Check for open/short circuit with switch open/closed.
12. JATCO ATCU ECU No detail available for this fault.

1. Mechanical problem within gearbox. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. Mechanical Problem Within Gearbox No detail available for this fault.
2. JATCO ATCU ECU No detail available for this fault.

1. Open Circuit CAN BUS. See step 1 under CHECK.
2. Open Circuit CAN BUS. See step 2 under CHECK.
3. Connectors CAN BUS. See step 3 under CHECK.
4. Instrument pack problem. See step 4 under CHECK.
5. ECM Problem. See step 5 under CHECK.
6. ATCU Problem. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit CAN BUS. Check resistance > 1 megohm.
2. OPEN_CIRCUIT Open Circuit CAN BUS. Check resistance > 1 megohm.
3. CONNECTOR Connectors CAN BUS. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
4. Instrument Pack Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.
5. ECM Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.
6. ATCU Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.

1. Open Circuit C932-33(YB) - C293-2(YB). See step 1 under CHECK.
2. Open Circuit C932-12(YN) - C293-5(YN). See step 2 under CHECK.
3. Connectors C932, C293, C233, C913 (K1.8), C371 (KV6), C331 (M47). See step 3 under CHECK.
4. Instrument pack problem. See step 4 under CHECK.
5. ECM Problem. See step 5 under CHECK.
6. ATCU Problem. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932-33(YB) - C293-2(YB). Check resistance > 1 megohm.
2. OPEN_CIRCUIT Open Circuit C932-12(YN) - C293-5(YN). Check resistance > 1 megohm.
3. CONNECTOR Connectors C932, C293, C233, C913 (K1.8), C371 (KV6), C331 (M47). Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
4. Instrument Pack Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.
5. ECM Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.
6. ATCU Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.

1. Open Circuit C932-33(YB) - C293-2(YB). See step 1 under CHECK.
2. Open Circuit C932-12(YN) - C293-5(YN). See step 2 under CHECK.
3. Connectors C932, C293, C233, C913 (K1.8), C371 (KV6), C331 (M47). See step 3 under CHECK.
4. Instrument pack problem. See step 4 under CHECK.
5. ECM Problem. See step 5 under CHECK.
6. ATCU Problem. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932-33(YB) - C293-2(YB). Check resistance > 1 megohm.
2. OPEN_CIRCUIT Open Circuit C932-12(YN) - C293-5(YN). Check resistance > 1 megohm.
3. CONNECTOR Connectors C932, C293, C233, C913 (K1.8), C371 (KV6), C331 (M47). Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
4. Instrument Pack Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.
5. ECM Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.
6. ATCU Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.

1. Open Circuit C932-33(YB) - C293-2(YB). See step 1 under CHECK.
2. Open Circuit C932-12(YN) - C293-5(YN). See step 2 under CHECK.
3. Connectors C932, C293, C233, C913 (K1.8), C371 (KV6), C331 (M47). See step 3 under CHECK.
4. Instrument pack problem. See step 4 under CHECK.
5. ECM Problem. See step 5 under CHECK.
6. ATCU Problem. See step 6 under CHECK.

1. OPEN_CIRCUIT Open Circuit C932-33(YB) - C293-2(YB). Check resistance > 1 megohm.
2. OPEN_CIRCUIT Open Circuit C932-12(YN) - C293-5(YN). Check resistance > 1 megohm.
3. CONNECTOR Connectors C932, C293, C233, C913 (K1.8), C371 (KV6), C331 (M47). Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
4. Instrument Pack Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.
5. ECM Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.
6. ATCU Problem The CAN BUS consists of two screened cables which connect several ECUs together allowing them to exchange information digitally at high speed. Failure of the CAN BUS will result in various ECUs setting fault codes and entering a fail-safe mode of operation. The failure of the CAN BUS can be caused by problems with any of the wiring or connectors which make up the bus or failure of an ECU connected to the bus (ECU faults are the least likely cause of failure). As the instrument pack handles CAN information from the ECUs the best place to diagnose CAN problems is by using the instrument pack diagnostic.

1. Engine sensor or ECU problem. See step 1 under CHECK.
2. JATCO ATCU ECU. See step 2 under CHECK.

1. Engine Sensor Or ECU Problem The JATCO ECU has reported a failure with one or more of: Engine RPM. Engine temperature. Engine torque reduction. Engine throttle angle. Engine virtual throttle angle. These signals are derived from the Engine Management ECU. The fault may be due to the sensor or the Engine Management ECU. Read Engine Management ECU fault codes and check if any of the above faults are set. If Textbook/T4 available, use the Engine Management diagnostics to investigate this fault in more detail.
2. JATCO ATCU ECU No detail available for this fault.

WIRING DIAGRAMS

For 2002 Freelander, see TRANSMISSION wiring diagram in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

For 2003 Freelander, see TRANSMISSION wiring diagram in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

For 2004 Freelander, see TRANSMISSION wiring diagram in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

WIRE COLORS

For wire color codes used in diagnostic tests, see WIRE COLOR CODES table.

WIRE COLOR CODES

See also:
• GEAR RATIOS
• WIRING DIAGRAMS