Diagnosis - zf5hp24 Automatic Transmission Land Rover Range Rover III

APPLICATION

Note. Automatic transmission will also be referred to as gearbox, and Electronic Automatic Transmission Electronic Control Unit (EAT ECU) will also be referred to as Transmission Control Module (TCM).

AUTOMATIC TRANSMISSION APPLICATIONS

IDENTIFICATION

The automatic transmission number is stamped on a plate attached to left side of automatic transmission casing, adjacent to gear selector. (Scheme 10)

Scheme 10

COMPONENT LOCATIONS

For transmission component locations (Scheme 11)- (Scheme 13).

Scheme 11

Scheme 12

Scheme 13

GENERAL

The ZF5HP24 transmission is an electronically controlled, five speed unit for use with the V8 petrol engine. The transmission is manufactured by ZF Transmissions GmbH in Saarbrucken, Germany.

The transmission is controlled by an Electronic Automatic Transmission (EAT) ECU which contains software to provide operation as a semi-automatic COMMANDSHIFT transmission. The EAT ECU allows the transmission to be operated as a conventional automatic unit by selecting P, R, N, D on the selector lever. Movement of the selector lever across the gate to the M/S position puts the transmission into electronic SPORT mode. Further movement of the lever in a lateral position to the + or - position puts the transmission into electronic manual COMMANDSHIFT mode.

The 5HP24 transmission has the following features

1. Designed to be maintenance free.
2. Transmission fluid is FILL FOR LIFE.
3. The torque converter features a controlled slip feature with electronically regulated control of lock-up, creating a smooth transition to the fully locked condition.
4. Shift programs controlled by the EAT ECU.
5. Connected to the ECM via the CAN for communications.
6. Default mode if major faults occur.
7. Diagnostics available from the EAT ECU via the ISO 9141 K Line.

The gearbox comprises three main casings; the bell housing, the intermediate plate and the main case. These items are bolted together to form the housing for the transmission components.

A fluid pan is bolted to the lower face of the main case and is secured with bolts. The fluid pan is sealed to the main case with a gasket. Removal of the fluid pan allows access to the valve block and solenoids and speed sensors. The fluid pan has four magnets located in each corner which collect any metallic particles present in the transmission fluid.

A non-serviceable fluid filter is located inside the fluid pan. If the transmission fluid becomes contaminated or after any service work the filter must be replaced.

The bell housing provides protection for the torque converter assembly and also provides the attachment for the gearbox to the engine block. The torque converter is a non-serviceable assembly which also contains the lock-up clutch mechanism. The torque converter drives a crescent type pump via drive tangs. The fluid pump is located in the intermediate plate, between the bell housing and the main case.

The main case contains the following components

1. Input shaft.
2. Output shaft.
3. Valve block and solenoids.
4. Three rotating multiplate drive clutches
5. Three fixed multiplate brake clutches.
6. One freewheel, one way, sprag type clutch.
7. A planetary gear train comprising three planetary gear sets.

Torque Converter

The torque converter is the coupling element between the engine and the gearbox and is located in the bell housing, on the engine side of the transmission. The driven power from the engine crankshaft is transmitted hydraulically and mechanically through the torque converter to the transmission. (Scheme 14) The torque converter is connected to the engine by a drive plate.

The torque converter comprises an impeller, a stator and a turbine. The torque converter is a sealed unit with all components located between the converter housing cover and the impeller. The two components are welded together to form a sealed, fluid filled housing.

The converter housing cover has four threaded bosses which provide for attachment of the engine drive plate which is connected to the engine crankshaft. The threaded bosses also provide for location of special tools which are required to removed the torque converter from the bell housing. With the impeller welded to the converter housing cover, the impeller is therefore driven at engine crankshaft speed.

Scheme 14

Impeller

The impeller outer body has a boss with two machined slots. (Scheme 15) The boss locates over the transmission input shaft and the slots engage with two tangs on the fluid pump. This arrangement allows the fluid pump to be driven at engine speed.

The impeller comprises a row of blades attached to the outer body. The root of the blades collect fluid which flows by centrifugal force around the curved outer surface of the impeller to the tip of the blades.

When the engine is running the rotating impeller acts as a centrifugal pump, picking up fluid at its center and discharging it at high velocity through the blades on its outer rim. The design and shape of the blades and the curve of the impeller body cause the fluid to rotate in a clockwise direction as it leaves the impeller. This rotation improves the efficiency of the fluid as it contacts the outer row of blades on the turbine.

The centrifugal force of the fluid leaving the blades of the impeller is passed to the curved inner surface of the turbine via the tip of the blades. The velocity and clockwise rotation of the fluid causes the turbine to rotate.

Scheme 15

Turbine

The turbine is similar in design to the impeller with a continuous row of blades. The fluid from the impeller enters the turbine through the tip of the blades and is directed around the curved body of the turbine to the root of the blades. (Scheme 15) The curved surface redirects the fluid back in the opposite direction to which it entered the turbine, effectively increasing the turning force applied to the turbine from the impeller. This principle is known as torque multiplication.

When the engine speed increases, the turbine speed also increases. The fluid leaving the inner row of the turbine blades is rotated in an counterclockwise direction due to the curve of the turbine and the shape of the blades. The fluid is now flowing in the opposite direction to the engine rotation and therefore the impeller. If the fluid was allowed to hit the impeller in this condition, it would have the effect of applying a brake to the impeller, eliminating the torque multiplication effect. To prevent this, the stator is located between the impeller and the turbine.

Stator

The stator is located on the splined transmission input shaft via a freewheel clutch. The stator comprises a number of blades which are aligned in an opposite direction to those of the impeller and turbine. The main function of the stator is to redirect the fluid returning from the turbine, changing its direction to that of the impeller.

The redirected fluid from the stator is directed at the inner row of blades of the impeller, assisting the engine in turning the impeller. This sequence increases the force of the fluid emitted from the impeller and thereby increases the torque multiplication effect of the torque converter.

If the turbine is rotating at a slower speed than the fluid from the impeller, the fluid will be deflected by the turbine blades in the path A. The fluid is directed at and deflected by the stator blades from path B to path "C". This ensures that the fluid is directed back to the pump in the optimum direction. In this condition the sprag clutch is engaged and the force of the fluid on the stator blades assists the engine in rotating the impeller. (Scheme 16)

As the rotational speed of the engine and therefore the turbine increases, the direction of the fluid leaving the turbine changes to path "D". The fluid is now directed from the turbine to the opposite side of the stator blades, rotating the stator in the opposite direction. To prevent the stator from resisting the smooth flow of the fluid from the turbine, the sprag clutch releases, allowing the stator to rotate freely on it shaft.

When the stator becomes inactive, the torque converter no longer multiples the engine torque. When the torque converter reaches this operational condition it ceases to multiply the engine torque and acts solely as a fluid coupling, with the impeller and the turbine rotating at approximately the same speed.

The stator uses a sprag type clutch. When the stator is rotated in a clockwise direction the sprags twist and are wedged between the inner and outer races. In this condition the sprags transfer the rotation of the outer race to the inner race which rotates at the same speed. Refer to ONE-WAY FREE WHEEL CLUTCH for further details of the sprag type clutch.

Scheme 16

Lock-Up Clutch Mechanism

The Torque Converter Clutch (TCC) is hydraulically controlled by an electronic pressure regulating solenoid (EPRS4) which is controlled by the EAT ECU. This allows the torque converter to have three states of operation as follows

1. Fully engaged.
2. Controlled slip variable engagement.
3. Fully disengaged.

The TCC is controlled by two hydraulic spool valves located in the valve block. These valves are actuated by pilot pressure supplied via a solenoid valve which is also located in the valve block. The solenoid valve is operated by PWM signals from the EAT ECU to give full, partial or no lock-up of the torque converter. (Scheme 17)

The lock-up clutch is a hydro-mechanical device which eliminates torque converter slip, improving fuel consumption. The engagement and disengagement is controlled by the EAT ECU to allow a certain amount of controlled SLIP. This allows a small difference in the rotational speeds of the impeller and the turbine which results in improved shift quality. The lock-up clutch comprises a piston and a clutch friction plate.

In the unlocked condition, the oil pressure supplied to the piston chamber and the turbine chamber is equal. Pressurized fluid flows through a drilling in the turbine shaft and through the piston chamber to the turbine chamber. In this condition the clutch plate is held away from the torque converter body and torque converter slip is permitted.

In the locked condition, the TCC spool valves are actuated by the electronic pressure regulating solenoid (EPRS4). The fluid flow in the unlocked condition is reversed and the piston chamber is vented. Pressurized fluid is directed into the turbine chamber and is applied to the clutch piston. The piston moves with the pressure and pushes the clutch plate against the torque converter body. As the pressure increases, the friction between the clutch plate and the body increases, finally resulting in full lock-up of the clutch plate with the body. In this condition there is direct mechanical drive from the engine crankshaft to the transmission planetary gear train.

Scheme 17

FLUID PUMP

The fluid pump is an integral part of the transmission. The fluid pump is used to supply hydraulic pressure for the operation of the control valves and clutches and also to pass the fluid through the transmission cooler.

The ZF5HP24 fluid pump is a crescent type pump and is located between the intermediate plate and the torque converter. (Scheme 18) The pump has a delivery rate of 16 cm 3 per revolution.

Scheme 18

The pump is driven by a positive coupling with the torque converter impeller, therefore the pump is driven at engine crankshaft speed.

The pump comprises a housing, a crescent spacer, an impeller and a ring gear. The housing has inlet and outlet ports to direct flow and is located in the intermediate plate by a centering pin. The pump action is achieved by the impeller, ring gear and crescent spacer.

The crescent spacer is fixed in its position by a pin and is located between the ring gear and the impeller. The impeller is driven by the drive from the torque converter which is located a needle roller bearing in the pump housing. The impeller teeth mesh with those of the ring gear. When the impeller is rotated, the motion is transferred to the ring gear which rotates in the same direction.

The rotational motion of the ring gear and the impeller collects fluid from the intake port in the spaces between the teeth. When the teeth reach the crescent spacer, the oil is trapped in the spaces between the teeth and is carried with the rotation of the gears. The spacer tapers near the outlet port. This reduces the space between the gear teeth causing a build up of fluid pressure as the oil reaches the outlet port. When the teeth pass the end of the spacer the pressurized fluid is passed to the outlet port.

The fluid emerging from the outlet port is passed through the fluid pressure control valve. At high operating speeds the pressure control valve maintains the output pressure to the gearbox at a predetermined maximum level. Excess fluid is relieved from the pressure control valve and is directed, via the main pressure valve in the valve block, back to the pump inlet port. This provides a pressurized feed to the pump inlet which prevents cavitation and reduces pump noise.

VALVE BLOCK & SOLENOID VALVES

The valve block is located in the bottom of the transmission and is covered by the fluid pan. The valve block houses electrical actuators, and control valves which provide all electro-hydraulic control for all transmission functions. (Scheme 19) The valve block comprises the following components

1. Five pressure regulator solenoids.
2. Three shift control solenoids.
3. Six dampers.
4. Twenty one hydraulic spool valves.
5. Manually operated selector valve.

Scheme 19

Pressure Regulator Solenoids

Five Electronic Pressure Regulator Solenoids (EPRS) are located in the valve block. (Scheme 19) The solenoids are controlled by PWM signals from the EAT ECU. The solenoids convert the electrical signals into hydraulic control pressure proportional to the signal to actuate the spool valves for precise transmission operation. (Scheme 20) EPRS4 is used for pressure regulation for the torque converter lock-up clutch.

Solenoid EPRS1 supplies a lower control pressure as the signal amperage increases. The EPRS1 solenoid is a normally closed regulating flow solenoid valve and regulates the main line pressure. The solenoid is used for adaptive pressure control. The EAT ECU operates the solenoid using PWM signals. The EAT ECU monitors engine load and clutch slip and varies the solenoid duty cycle accordingly.

Solenoids EPRS2, 3 and 5 supply a higher control pressure as the signal amperage increases. The solenoids are normally open solenoids regulating flow solenoid valves. The solenoids are used to regulate the supply of fluid pressure for clutch application during overlap up and down shifts of gears 2-3, 3-4 and 4-5. The EAT ECU operates the solenoids using a PWM earth proportional to the required increasing or decreasing clutch pressures.

The resistance of the coil winding for solenoid EPRS1 is between 5.4-6.4 ohms at 20°C (68°F). The resistance of the coil windings for solenoids EPRS2, 3, 4 and 5 is between 5.9-6.9 at 20°C (68°F).

Scheme 20

Shift Control Solenoids

Spring Three shift control Solenoid Valves (SV) are located in the valve block. (Scheme 19) The solenoids are controlled by the EAT ECU and convert electrical signals into hydraulic control signals to control clutch application. (Scheme 21)

The shift control solenoids SV1, 2 and 3 are normally closed, ON/OFF solenoids which are controlled by the EAT ECU switching the solenoid to earth. The EAT ECU also supplies the power to solenoids. The EAT ECU energizes the solenoids in a programmed sequence for clutch application for gear ratio changes and shift control.

The resistance of the coil winding for solenoids SV1, 2 and 3 is between 26.0-30.4 ohms at 20°C (68°F).

Scheme 21

Dampers

There are six dampers located in the valve block. Four of the dampers are used to regulate and dampen the regulated pressure supplied via the pressure regulating solenoid valves. The two remaining dampers are used for operation of clutches "A" and "C" and providing damping of the fluid pressure during shift changes. All of the dampers are load dependent through modulation of the damper against its return spring pressure.

The dampers comprise a piston, a housing bore and a spring. The piston is subject to the pressure applied by the spring. The bore has a connecting port to the function to which it applies. Fluid pressure applied to the applicable component (i.e. a clutch) is also subjected to the full area of the piston, which moves against the opposing force applied by the spring. The movement of the piston creates an action similar to a shock absorber, momentarily delaying the build up of pressure in the circuit. This results in a more gradual application of clutches improving shift quality.

Spool Valves

The valve block contains twenty one spool valves which control various functions of the transmission. The spool valves are of conventional design and are operated by fluid pressure.

Each spool valve is located in its spool bore and held in a default (unpressurized) position by a spring. The spool bore has a number of ports which allow fluid to flow to other valves and clutches to enable transmission operation. Each spool has a piston which is waisted to allow fluid to be diverted into the applicable ports when the valve is operated.

When fluid pressure moves a spool, one or more ports in the spool bore are covered or uncovered. Fluid is prevented from flowing or is allowed to flow around the applicable waisted area of the spool and into another uncovered port. The fluid is either passed through galleries to actuate another spool, operate a clutch or is returned to the fluid pan.

DRIVE CLUTCHES

There are three drive clutches and three brake clutches used in the 5HP24 transmission. Each clutch comprises one or more friction plates dependent on the output controlled. A typical clutch consists of a number of steel outer plates and inner plates with friction material bonded to each face. (Scheme 22)

The clutch plates are held apart mechanically by a diaphragm spring and hydraulically by dynamic pressure. The pressure is derived from a lubrication channel which supplies fluid to the bearings etc. The fluid is passed via a drilling in the output shaft into the chamber between the baffle plate and the piston. To prevent inadvertent clutch application due to pressure build up due to centrifugal force, the fluid in the dynamic pressure equalization chamber overcomes any pressure in the piston chamber and holds the piston off the clutch plate assembly.

When clutch application is required, main pressure from the fluid pump is applied to the piston chamber from the supply port. This main pressure overcomes the low pressure fluid present in the dynamic pressure equalization chamber. The piston moves, against the pressure applied by the diaphragm spring, and compresses the clutch plate assembly. When the main pressure falls, the diaphragm spring pushes the piston away from clutch plate assembly, disengaging the clutch.

Scheme 22

ONE-WAY FREE WHEEL CLUTCH

The ZF 5HP24 transmission uses only one free wheel clutch to perform a component holding function. The free wheel clutch, in conjunction with the hydraulic clutches, prevent disruption of the power output during shift changes. The freewheel clutch is located at the rear of the planetary gearset and controls brake clutch F.

The free wheel clutch can perform three functions; hold components stationary, drive components and free wheel allowing components to rotate without a drive output. The free wheel clutch used in the 5HP24 transmission is of the sprag type and comprises an inner and outer race and a sprag and cage assembly. The inner and outer races are pressed into their related components with which they rotate. The sprag and cage assembly is located between the inner and outer races.

The sprags are located in a cage which is a spring which holds the sprags in the WEDGE direction and maintains them in contact with the inner and outer races.

Referring to the illustration, the sprags are designed so that the dimension "B" is larger than the distance between the inner and outer race bearing surfaces. (Scheme 23) When the outer race rotates in a clockwise direction, the sprags twist and the edges across the dimension "B" wedge between the races, providing a positive drive through each sprag to the inner race. The dimension "A" is smaller than the distance between the inner and outer race bearing surfaces. When the outer race rotates in an counterclockwise direction, the dimension "A" is too small to allow the sprags to wedge between the races, allowing the outer race to rotate freely.

On the illustration shown, when the outer race is rotated in a clockwise direction, the sprags twist and are WEDGE between the inner and outer races. The sprags then transfer the rotation of the outer race to the inner race, which rotates at the same speed.

Scheme 23

PLANETARY GEAR TRAIN

The planetary gear train used on the 5HP24 transmission comprises three planetary gearsets which together form a compound gear train. The gearset operates in conjunction with the clutches, brakes and freewheel clutch to produce five forward gears and one reverse gear. (Scheme 24)

The planetary gear train is a single integral assembly which comprises the following components

1. Three single planet carrier gearsets connected in series. (Scheme 25)and (Scheme 26).
2. A single sun gear.
3. A twin sun gear.
4. Three ring gears.

Scheme 24

Scheme 25

Scheme 26

POWER FLOWS

Operation of the transmission is controlled by the EAT ECU which electrically activates various solenoids to control the transmission gear selection. The sequence of solenoid activation is based on programmed information in the ECU memory and physical transmission operating conditions such as vehicle speed, engine load, throttle position and selector lever position.

Engine torque is transferred, via operation of single or combinations of clutches, to the planetary gear train. The planetary gear train is controlled by reactionary inputs from brake clutches and the freewheel clutch to produce five forward gears and one reverse gear. (Scheme 27)

The following tables show which clutches are operating for selected gear ratios and which solenoids are activated to produce the required torque output from the transmission. (Scheme 28)and (Scheme 29).

Scheme 27

Scheme 28

Scheme 29

1st Gear (D Selected)

The gear selector lever and the manual selector valve spool are in the "D" position. (Scheme 30) Engine torque is transmitted from the torque converter to the planet gearset 3. The torque is applied to the input shaft gear via the application of clutch "A". The freewheel clutch locks the planet carrier of gearset 2 in the direction of rotation.

The larger diameter input shaft gear drives the planet gears of gearset 3, which rotate inside the locked ring gear 3. This rotation is passed via the planet carrier of gearset 3 to the output shaft.

In 1st gear with braking effect when coasting, the brake clutch "F" is also applied locking the ring gear 3 in both directions. (Scheme 31)

Scheme 30

Scheme 31

2nd Gear (D Selected)

The gear selector lever and the manual selector valve spool are in the "D" position. (Scheme 32) Engine torque is transmitted from the torque converter to the planet gearset 3. The torque is applied to the input shaft gear via the application of clutch "A".

The clutch "E" is applied which locks the planet carrier of gearset 1. (Scheme 33) The planet carrier is physically connected to the ring gear 2 which is subsequently also locked.

The small diameter input shaft gear drives the planet gears of gearset 2, which rotate around the stationary ring gear 2 in the direction of engine rotation. The planet carrier of gearset 2 is physically connected to the ring gear 3 which subsequently rotates in the same direction. The rotation of the ring gear 3 is transmitted to the planet gearset 3, which rotates around the large diameter gear of the input shaft gear. The rotation is passed via the planet carrier of gearset 3 to the output shaft which rotates at an increased speed compared to 1st gear.

Scheme 32

Scheme 33

3rd Gear (D Selected)

The gear selector lever and the manual selector valve spool are in the "D" position. (Scheme 34) Engine torque is transmitted from the torque converter through the input shaft gear via the application of clutch "A". Clutch brake "D" is applied and holds the intermediate shaft gear stationary. (Scheme 35)

Ring gear 1 is driven by the planet gearsets 2 and 3. The torque applied to ring gear 1 is passed via the stationary intermediate shaft gear to the planet carrier of gearset 1. The planet carrier of gearset 1 is physically connected to the ring gear 2. This causes the planet carrier of gearset 2 to rotate at a higher speed. Because the planet carrier of gearset 2 is physically connected to the ring gear 3, the ring gear 3 rotates in the same direction. This causes the ring gear 3 and subsequently the planet carrier of gearset 3 and the output shaft to rotate at an increased speed compared to 2nd gear.

Scheme 34

Scheme 35

4th Gear (D Selected)

The gear selector lever and the manual selector valve spool are in the "D" position. (Scheme 36) Engine torque is transmitted from the torque converter to the input shaft gear via clutch A and the planet carrier of gearset 2 via the clutch "B". (Scheme 37) The planet carrier of gearset 2 is physically connected to the ring gear 3 and this drive is transmitted, via the ring gear 3 and the planet gears and carrier of gearset 3 to the output shaft, which rotates at an increased speed compared to 3rd gear.

The drive transmitted from the planet carrier of gearset 2 and the input shaft gear to planet gearset 3 results in a complete locking of the planetary gear train. Therefore, in this condition the engine input speed is identical to the output shaft speed creating a 1:1 output ratio.

Scheme 36

Scheme 37

5th Gear (D Selected)

The gear selector lever and the manual selector valve spool are in the "D" position. (Scheme 38) Engine torque is transmitted from the torque converter to the planet carrier of gearset 2 via the application of clutch "B". Clutch "D" is applied to lock the intermediate shaft gear. (Scheme 39)

The planet carrier of gear 2 is physically connected to the ring gears 1 and 3 and drives them at the same speed. The rotation of ring gear 1 is passed to the planet gears of gearset 1 which rotate around the locked intermediate shaft gear. The rotation of the planet gears is passed through the planet carrier of gearset 1 to the ring gear 2, to which it is physically connected.

The rotation of the ring gear 2 is passed to the planet gears of gearset 2 which in turn rotates the small diameter gear of the input shaft gear. This rotation is then passed, via the larger diameter gear of the input shaft gear, to the planet gears of gearset 3 in the direction of engine rotation.

This rotation of the planet gears of gearset 3 increases the rotational speed of the planet carrier of gearset 3 and subsequently drives the output shaft at an increased speed compared to 4th gear.

Scheme 38

Scheme 39

Reverse Gear (R Selected)

The gear selector lever and the manual selector valve spool are in the "R" position. (Scheme 40) Engine torque is transmitted from the torque converter to the intermediate shaft gear. The torque is applied to the intermediate shaft gear via the application of clutch "C".

Clutch "F" is applied and holds the ring gears 1 and 3 stationary and subsequently the planet carrier of gearset 2 which is physically connected to ring gear 3. (Scheme 41)

The intermediate shaft gear drives the planet gears of gearset 1 which in turn rotate around the locked ring gear 1. The rotation of the planet carrier of gearset 1 is transferred to the ring gear 2 to which it is physically connected. The rotation of ring gear 2 is transferred to the planet gears of gearset 2. Because the planet carrier of gearset 2 is held by clutch "F", the drive is passed from the planet gears to the small gear on the input shaft gear.

The rotation is transferred via the large gear on the input shaft gear to the planet gears of gearset 3, which rotate around the stationary ring gear 3. The rotation of the planet gears rotates the planet carrier of gearset 3 which in turn rotates the output shaft in the reverse direction to that of the forward gears.

Scheme 40

Scheme 41

SENSORS

The ZF 5HP24 transmission contains two speed sensors and a temperature sensor. The sensors are located inside the transmission housing, with the speed sensors being the only serviceable items.

The sensors play an important part in the operation of the transmission and provide signal information to the EAT ECU. This information is used by the ECU to control shift timing and fluid temperature to provide the optimum operating condition for the transmission.

Transmission Speed Sensors

Two speed sensors are used in the 5HP24 transmission to monitor turbine speed and output shaft speed. (Scheme 42)

The turbine speed sensor is monitored by the EAT ECU to calculate the slip of the torque converter clutch and internal clutch slip. This allows the EAT ECU to accurately control the slip timing during shifts and adjust clutch application or release pressure for overlap shift control.

The output shaft speed is monitored by the EAT ECU and compared to engine speed signals received on the CAN from the ECM. Using the comparison of the two signals the EAT ECU calculates the transmission slip ratio for plausibility and maintain adaptive pressure control.

The turbine speed sensor is located in the main casing and secured with a screw. The sensor monitors turbine speed from a toothed target wheel which on the outer diameter of clutch "B" housing.

The output shaft speed sensor is located at the rear of the main casing and secured with a screw. The sensor monitors the output shaft speed from a toothed target wheel which is an integral part of the park lock gear.

Both sensors are of the inductive type and are connected to the EAT ECU with two wires. The EAT ECU supplies a positive DC supply and a signal return wire to monitors the sensor signals. Both wires are covered by a screen which is connected to ground by the EAT ECU.

The sensor receives the DC supply from the EAT ECU. As the teeth of the target wheel pass the sensor tip, a change in the magnetic field of the sensor occurs and generates an AC pulse in the sensor field winding. The pulse is passed on the negative (ground) wire to the EAT ECU which calculates the rotational speed. The AC pulse generated is proportional to the rotational speed of the target wheel. The EAT ECU measures the peak to peak outputs of the AC waveform to calculate the rotational speed being measured.

The resistance of the coil winding in each sensor is between 285-365 ohms at 20°C (68°F). Failure of either speed sensor will cause the EAT ECU to store a related fault code.

Scheme 42

Transmission Temperature Sensor

The temperature sensor is located inside the wiring harness in the fluid pan and is connected to the EAT ECU with two wires. (Scheme 43) The sensor is a Positive Temperature Coefficient (PTC) sensor which has a semi-conductor material which increases its resistance as the temperature increases.

The sensor receives a predetermined current from the EAT ECU on one of the wires and is connected to earth via the ECU on the second wire. The EAT ECU measures the returned voltage and using this information calculates the fluid temperature.

In the case of low fluid temperatures, the EAT ECU prohibits torque converter lock-up to promote faster fluid warm up. In the case of high fluid temperatures, the EAT ECU increases the converter lock-up control and modifies the shift program to reduce fluid temperature.

If the temperature sensor fails, the EAT ECU uses a programmed default temperature value. The default value is derived from the engine coolant temperature sensor and received on the CAN from the ECM. A fault code is stored in the ECM which can be retrieved using TestBook/T4.

The temperature sensor has a semi-conductor material with resistance to temperature. See TEMPERATURE SENSOR RESISTANCE VALUES table.

TEMPERATURE SENSOR RESISTANCE VALUES

Scheme 43

INHIBITOR SWITCH

The inhibitor switch is located externally on the right hand side of the transmission. (Scheme 44) The switch is located on the selector shaft and secured to the main casing with screws. A protective cover is also fitted over the switch to prevent impact damage. The switch rotates with the selector shaft, moving the switch contacts to correspond to the selected program. The switch provides signals which allows the EAT ECU to monitor the position of the manual selector spool valve and the selected drive program.

The switch is connected via an integral harness and multiplug on five wires to the EAT ECU. One of the wires supplies a 12V supply to the switch. The remaining wires are connected to the EAT ECU. When the transmission selector lever is moved to the selected position, one or more of the contacts within the switch are made, completing a circuit back to the ECU. From the switch contacts which are made, the ECU determines which selection is required and responds accordingly.

When the selector lever is in Park, the EAT ECU transmits a signal to the immobilization ECU to enable starter operation. The signal also energizes the starter relay, allowing the crank signal from the immobilization ECU to pass to the starter solenoid.

For which switch contacts are made for a given selector lever position, see SELECTOR LEVER POSITION SWITCH CONTACTS table.

SELECTOR LEVER POSITION SWITCH CONTACTS

Scheme 44

TRANSMISSION FLUID COOLING

The fluid cooler is located at the bottom right hand corner of the engine. The cooler is cooled by engine coolant which flows in a water jacket around cores within the cooler body. Transmission fluid enters the cooler and flows through the cores where it is cooled by the engine coolant. (Scheme 45) The fluid leaves the cooler and is passed back to the transmission. The transmission fluid is pumped through the cooler by the transmission fluid pump.

The fluid cooler has a thermostatic valve which is opened by transmission fluid temperature. The thermostatic valve is opened at a transmission fluid temperature of 80°C (176°F) and allows engine coolant to flow through the fluid cooler.

Scheme 45

Gear Selector Lever

The gear selector lever assembly is located in a central position on the transmission tunnel, between the front driver and passenger seats. A mounting plate is secured to the transmission tunnel and provides the mounting for the selector lever assembly.

The selector lever comprises a cast mounting plate which provides for the location of the selector components. The lever is connected to a gimbal mechanism which allows for the selection of P, R, N, D is a forward or backward direction and selection between automatic and manual/sport in a left/right transverse direction. (Scheme 46) When manual/sport mode is selected, the lever can be moved in a forward or backward direction to select + or - for manual (CommandShift) operation.

When the selector lever is moved to the M/S position, the Bowden cable to the transmission is mechanically disconnected at the shifter. If left in Sport mode all gear changes are performed automatically. If Manual (CommandShift) mode is selected, all gear changes are based on switched ground inputs received by the EAT ECU from the Manual +/- CommandShift switch.

The selector lever mechanism houses the following components

1. Manual +/- CommandShift switch.
2. Shift interlock solenoid.
3. High/Low range selector switch.
4. Hill Descent Control (HDC) switch.
5. Selector position LED display.
6. Selector lever position switch.
7. Manual/Sport switch.
8. Key interlock mechanism.

There are four selector lever positions and two additional positions for manual/sport operation

1. P (Park) Prevents the vehicle from moving by locking the transmission.
2. R (Reverse) Select only when the vehicle is stationary and the engine is at idle.
3. N (Neutral) No torque transmitted to drive wheels.
4. D (Drive) This position uses all five forward gears in high and low ranges.
5. M/S (Sport Mode) This position uses all five forward gears as in D, but will upshift at higher engine speeds improving acceleration.
6. + & - (Manual COMMANDSHIFT Mode) Movement of the selector lever in the +/- positions, when the lever is in the M/S position, will operate the transmission 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 selector position LED display and in the instrument pack. In COMMANDSHIFT mode, if a gear is selected but the EAT ECU logic prevents selection of that gear, the requested gear will be initially displayed. The EAT ECU will engage the next allowed gear and then display that gear.

Scheme 46

Manual +/- CommandShift Switch

The manual +/- switch is located on the left hand side of the selector lever assembly. The switch comprises a housing which provides the location for a sliding contact. When the selector lever is moved to the manual/sport position, a dog on the lever engages with a slotted abutment on the switch sliding contact. When the lever is moved to the + or - position the dog moves the switch completing a momentary earth circuit with one of two microswitches at each end of the switch which correspond to the + or - positions.

This momentary signal is received by the EAT ECU which, on first operation of the switch, initiates manual mode and operates the transmission in the selected gear.

In this position, a spring will move the selector lever to the center position when released.

Shift Interlock Solenoid

The shift interlock solenoid is located at the front of the selector lever assembly. The selector lever is connected to a locking plate which has two holes which correspond to the P and N positions. When the ignition is on or the engine is running, the solenoid is energized by the EAT ECU when the selector lever is in the P or N positions. When energized, the solenoid ejects a pin which engages in the locking plate preventing the lever from being moved.

When the footbrake is applied, a signal from a brake switch is passed to the EAT ECU which de-energizes the solenoid allowing the lever to be moved from the P or N position. This prevents the selector from being moved to the D or R position unintentionally and the application of the brakes also prevents the vehicle CREEPING when the gear is engaged.

Movement of the selector lever from the P or N positions is also prevented if the EAT ECU senses that the engine speed is above 2500 rev/min, even if the brake pedal is depressed.

High/Low Range Selector Switch

The high/low range switch is located on the selector lever cover, on the right hand side of the selector lever. The switch can be identified by the a high/low range legend graphic and the switch lever is colored white. High or low range can be selected using this switch providing the vehicle speed is within defined limits and the gear selector lever is in the neutral position. + TRANSFER BOX, DESCRIPTION AND OPERATION, Description.

Hill Descent Control (HDC) Switch

The HDC switch is located on the selector lever cover, on the left hand side of the selector lever. The switch can be identified by the HDC legend graphic and the switch lever is colored yellow. Operation of the HDC switch it not directly related to automatic transmission operation. + BRAKES, DESCRIPTION AND OPERATION, Foundation Brakes.

Selector Position LED Display

The selector position LED display is located on the selector lever cover, between the HDC and high/low range switches. The display has a graphic which shows the lever positions P, R, N, D, M/S and +/-. The P, R, N, D and M/S positions each have a small, Red LED which illuminates when that position is selected. The +/- positions do not have an LED.

The LED display is controlled by the selector lever position switch, with the two components connected via a five wire ribbon cable. The LED display is powered from the Body Control Unit (BCU) and remains illuminated until the BCU is in sleep mode. The LED display is active at all times when the ignition is on.

Selector Lever Position Switch

The selector lever position switch is located on the right hand side of the selector lever assembly. The switch has a moving contact which is connected to the selector lever. As the lever is moved, the sliding contact moves in the switch completing a circuit with four further contacts in the switch which represent the four lever positions; P, R, N and D. The switch is connected to the selector position LED display via a ribbon cable and provides the power for the display LED's. The switch receives its power supply from the BCU.

Manual/Sport Switch

The manual/sport switch is located at the rear of the selector lever assembly. The manual/sport switch is a cam operated microswitch. A lever with a roller is attached to the switch body. When the selector lever is moved from the automatic D position to the manual/sport M/S position, the roller contacts a cam on the selector lever which depresses the switch lever and operates the switch. The switch contacts remain closed when the selector lever is in the manual/sport position.

The operation of the switch completes an earth path which is sensed by the EAT ECU which switches the transmission operation to sport when M/S is selected and deselects sport mode when D (automatic operation) is reselected. The completed earth path is connected to the EAT ECU via the M/S LED on the selector lever display which is illuminated by an output from the ECU when M/S is selected.

Selector Cable

The selector cable is a Bowden type cable that connects the selector lever to the manual selector spool valve. A "C" clip secures the outer cable to the selector lever assembly. The inner cable is secured to an arm which is connected to the selector lever via a "U" shaped bracket and pin. The transmission end of the outer cable is secured to a bracket on the transmission by a clamp nut.

The transmission has an operating lever which is attached to and operates the manual selector control spool valve. The inner cable is attached to the operating lever by a clamp bush and locknut. The clamp bush allows for the adjustment of the selector cable.

Key Interlock Mechanism

The key interlock mechanism prevents the key from being removed from the ignition switch when the selector lever is any position other than P PARK. This prevents the vehicle being accidentally left in neutral which would cause the vehicle to move if the handbrake was not applied.

The mechanical mechanism is operated by a Bowden cable which is attached between the selector lever assembly and the ignition switch. (Scheme 47) When the ignition switch is turned to the on position, the switch rotates a lever which in turn pulls the cable. This lifts a latch in the selector lever assembly which is engaged with the selector lever when in the P position.

Scheme 47

Instrument Pack

The instrument pack is connected to the EAT ECU via the CAN. Transmission status is transmitted by the EAT ECU and displayed to the driver on one of two displays in the instrument pack. (Scheme 48)

Scheme 48

Malfunction Indicator Lamp (MIL)

The MIL is located in the lower left hand corner of the instrument pack, below the fuel gauge. Transmission related faults which may affect the vehicle emissions output will illuminate the MIL.

The MIL is illuminated by the ECM on receipt of a relevant fault message from the EAT ECU on the CAN. The nature of the fault can be diagnosed using TestBook/T4 which reads fault codes stored in the ECU memory.

Transmission Status Display

The transmission status display is located on the right hand side of the instrument pack, below the tachometer. The display shows the selector lever position and in the case of manual (CommandShift) mode, the selected gear. (Scheme 49) The selector lever position and gear selected displays are illuminated in a green color when active.

Additionally, the display also shows a low range symbol when low range is selected on. The low range symbol is illuminated in an amber color when active. When the transfer box is changing from low to high range, the low range symbol flashes until the range change is complete.

Scheme 49

Message Center Display

The message center is located below the speedometer and the tachometer at the bottom of the instrument pack. The message center is a Liquid Crystal Display (LCD) to relay vehicle status information to the driver. The message center can display the following transmission related messages

1. SPORT MODE
2. MANUAL MODE
3. SELECT NEUTRAL
4. TRANSMISS'N OVERHEAT
5. TRANSMISS'N FAILSAFE PROG
6. LOW RANGE
7. HIGH RANGE
8. SLOW DOWN

Electronic Automatic Transmission (EAT) ECU

The Electronic Automatic Transmission (EAT) ECU is the controlling component of the transmission. The ECU software was designed in conjunction with Land Rover, Bosch and ZF Getriebe GmbH.

The EAT ECU is located in the E-box, which is positioned forward of the RH suspension top mount. (Scheme 50) The ECU is secured in a clip adjacent to the ECM. The ECU has a blue connector socket color which assists identification.

The E-box has a temperature controlled environment which maintains the optimum temperature for ECU operation.

The EAT ECU uses three harness connectors for all input and output information.

Scheme 50

Inputs & Outputs

The sensor signals allow the EAT ECU to monitor transmission operation. The ECU processes the incoming signals and compares this with data stored in its memory. If the received signals are not within the stored values, the ECU will make adjustments to the transmission operation using the solenoids to provide optimum driveability and performance.

The sensor inputs provide the EAT ECU with a constant update of the operating condition of the transmission and the engine. The ECU compares this input data with mapped information stored in its memory and will make any required adjustments.

EAT ECU HARNESS CONNECTOR C0193 PIN DETAILS

EAT ECU HARNESS CONNECTOR C0932 PIN DETAILS

EAT ECU HARNESS CONNECTOR C1835 PIN DETAILS

MAIN RELAY

The main relay is located inside the E-box and is identified by its blue color. The relay is connected directly from the battery via a 100 Amp remote fuse. The relay coil is controlled by the ECM which provides a ground for the coil when the relay is energized.

When energized, the main relay supplies battery voltage, via fuse 1 in the engine compartment fusebox, to the EAT ECU.

DIAGNOSTICS

The diagnostic socket is located in the fascia, in the driver's side stowage tray. The socket is secured in the fascia panel and is protected by a hinged cover.

The diagnostic socket allows the exchange of information between the various ECU's on the bus systems and TestBook/T4 or a diagnostic tool using Keyword 2000 protocol. (Scheme 51) The information is communicated to the socket via a diagnostic ISO9141 K Line. This allows the retrieval of diagnostic information and programming of certain functions using TestBook/T4 or a suitable diagnostic tool.

The EAT ECU uses a P code strategy which stores industry standard and Land Rover specific Diagnostic Trouble Codes (DTC) relating to faults. See TRANSMISSION "P" CODES table.

Scheme 51

TRANSMISSION "P" CODES

CONTROLLER AREA NETWORK (CAN)

The CAN is a high speed broadcast bus network connected between the following electronic units

1. EAT ECU
2. ECM
3. Transfer box ECU
4. Air suspension ECU
5. Instrument pack
6. ABS ECU
7. Steering angle ECU

The CAN allows fast exchange of data between ECU's. The CAN comprises two wires which are identified as CAN high (H) and CAN low (L). The two wires are colored Yellow/Black (H) and Yellow/Brown (L) and are twisted together to minimize electromagnetic interference (noise) produced by the CAN messages. (Scheme 52)

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

1. Transmission operates in default mode.
2. Torque converter lock-up control is disabled.
3. ECM to EAT ECU engine torque reduction message inoperative.
4. Gear position display in instrument pack inoperative.

Scheme 52

GEAR RATIOS

GEAR RATIOS

Different Driving Modes

There are a number of different driving modes of operation. Some can be selected by the driver and some are automatically initiated by the EAT ECU during driving

1. Normal mode. See «NORMAL MODE»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__normal-mode) .
2. Sport mode. See «SPORT MODE»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__sport-mode) .
3. Manual (CommandShift) mode. See «MANUAL (COMMANDSHIFT) MODE»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__manual-commandshift-mode) .
4. Engine warm up mode. See «ENGINE WARM-UP MODE»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__engine-warm-up-mode) .
5. Hill Descent Control (HDC) mode. See «HDC MODE»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__hdc-mode) .
6. Cruise mode. See «CRUISE MODE»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__cruise-mode) .
7. Hill mode. See «HILL MODE»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__hill-mode) .
8. Default (Limp home) mode. See «DEFAULT (LIMP HOME) MODE»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__default-limp-home-mode) .
9. Reverse lock-out mode. See «REVERSE LOCK-OUT MODE»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__reverse-lock-out-mode) .
10. Cooling strategy. See «COOLING STRATEGY»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission__cooling-strategy) .

Normal Mode

Normal mode is automatically selected by the EAT ECU on power up. In this mode all automatic and adaptive modes are active. Normal mode uses gear shift and lock-up maps to allow vehicle operation which is a compromise between performance, fuel consumption and emissions. If the transmission is operated in sport or manual mode and the selector lever is moved to the D position, normal mode is automatically resumed.

Sport Mode

The sport mode operates in high range only and provides enhanced acceleration and responsiveness. In sport mode the EAT ECU uses shift maps which allow the transmission to downshift more readily, hold gears for longer at higher engine speeds, and limits the transmission to 4th gear.

Sport mode is selected by moving the selector lever to the left into the M/S position. When the sport mode is first selected, SPORT is displayed in the message center for 6 seconds and, if 5th gear is currently engaged, the EAT ECU downshifts to 4th.

Manual (CommandShift) Mode

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

Shift maps are provided for manual mode to protect the engine at high engine speeds. The EAT ECU will automatically change up to a higher gear ratio to prevent engine overspeed and change down to a lower gear ratio to avoid engine laboring and stalling.

When kickdown is requested the EAT ECU downshifts at least 2 gears.

When the vehicle is stationary, to drive off the driver can select 1st gear in high range, or 1st, 2nd or 3rd gear in low range. Any other gear selection will be rejected by the EAT ECU.

When driving off, upshifts can be pre-selected by making + selections with the selector lever for the number of upshifts required. The EAT ECU then automatically performs a corresponding number of upshifts when the appropriate shift points are reached. So, for example, when starting off in 1st gear, if three + selections are made in quick succession, the EAT ECU will automatically change up through the box to 4th gear as the vehicle accelerates, without any further selections being made.

In manual mode a low gear can be selected to provide engine braking for descending a slope without HDC or continuous use of the brake pedal. The driver can prepare for the end of the descent by moving the selector lever to D. The EAT ECU will maintain the low gear and only revert to automatic shift control when the throttle is opened and vehicle speed increases.

Engine Warm-Up Mode

The EAT ECU monitors the output from the transmission fluid temperature sensor in the transmission and also receives an ECT sensor signal from the ECM on the CAN. When the transmission fluid and/or the engine coolant temperature is less than 60°C (140°F), the EAT ECU initiates the shift maps used in sport mode, when driving after a cold start.

The sport mode shift points raise the engine speed. This, in turn, promotes faster transmission fluid warm-up and also decreases the warm-up time for the catalytic converter to reach optimum temperature.

The warm-up mode is terminated if the vehicle speed exceeds 37 mph (60 km/h), the transmission fluid or the engine coolant temperature exceeds 60°C (140°F) or a maximum time of 3 minutes is exceeded.

HDC Mode

When HDC is selected, the ABS module requests a special shifting pattern to be activated within the transmission which selects and holds lower gears when appropriate to increase engine braking.

Cruise Mode

When cruise control is activated, the EAT ECU receives a cruise active message on the CAN. The EAT ECU activates a cruise control map which prevents locking and unlocking of the torque converter clutch and minimizes up and down shifts. If cruise control is operative and the vehicle speed increases due to coasting downhill, the ECM can request a down shift via a CAN message if the vehicle speed exceeds the set cruise limit.

Hill Mode

Hill mode is initiated by the EAT ECU when high engine torque, high throttle angle and low engine speed is detected via ECM signals on the CAN. The EAT ECU defines this combination of signals to determine when the vehicle is travelling on a steep gradient.

In hill mode the EAT ECU adopts one of three shift maps which hold the transmission in low gears throughout the ascent. The shift map chosen depends on the severity of the slope as determined from the engine signals.

Hill mode can also be initiated when the vehicle is at very high altitudes.

Default (Limp Home) Mode

If a transmission fault is detected by the EAT ECU, the ECU adopts a limp home mode strategy. 'TRANS. FAILSAFE' is displayed in the message center and, if the fault has an effect on engine emissions, the MIL will also be illuminated.

In default mode, P, R and N functions operate normally (if the fault allows these selections) and the EAT ECU locks the transmission in 4th gear to allow the driver to take the vehicle to the nearest dealer. The torque converter lock-up clutch is disabled and reverse lock-out will not function.

If the vehicle is topped and subsequently restarted in the default mode condition, the EAT ECU operates normally until the fault which caused the condition is detected again.

Reverse Lock-Out Mode

When the vehicle is travelling forwards, selecting reverse could cause transmission damage. To protect against this, reverse gear is prohibited if the vehicle is travelling forwards at a road speed above 5 mph (8 km/h).

Cooling Strategy

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

If the transmission fluid temperature increases to 140°C (284°F) or higher, the EAT ECU employs the cooling strategy.

The strategy uses a specific shift and torque converter lock-up clutch map. This map allows torque converter clutch lock-up and gear shifts to operate outside of their normal operation. This will reduce the engine speed and/or slip in the torque converter, therefore reducing heat generated by the engine and the transmission.

The cooling strategy is cancelled when the transmission fluid temperature decreases to 130°C (266°F) or below.

TRANSMISSION FAULT STATUS

If the EAT ECU detects a fault with the transmission system, it will enter a default mode to prevent further damage to the transmission and allow the vehicle to be driven.

When a fault is detected a CAN message is sent from the EAT ECU and is received by the instrument pack. The instrument pack illuminates the MIL and displays TRANS. FAILSAFE in the message center.

Some transmission faults may not illuminate the MIL or display a fault message, but the driver may notice a reduction in shift quality.

ENGINE SPEED & THROTTLE MONITORING

The ECM constantly supplies the EAT ECU with information on engine speed and throttle angle through messages on the CAN. The EAT ECU uses this information to calculate the correct and appropriate timing of shift changes.

If the messages are not received by the ECM, the EAT ECU will implement a back-up strategy to protect the transmission from damage and allow the vehicle to be driven.

In the event of an engine speed 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 shift changes.
2. No kickdown.
3. Torque reduction request inhibited.

INTRODUCTION

The ZF5HP24 transmission is an electronically controlled, five speed unit for use with the V8 petrol engine. The transmission is manufactured by ZF Transmissions GmbH in Saarbrucken, Germany. The transmission is controlled by a Transmission Control Module (TCM) that contains software to provide operation as a semi-automatic STEPTRONIC transmission. The TCM allows the transmission to be operated as a conventional automatic unit by selecting Park, Reverse, Neutral, and Drive on the selector lever. Movement of the selector lever across the gate to the M/S position puts the transmission into electronic SPORT mode. Further movement of the lever in a lateral position to the + or - position puts the transmission into electronic manual COMMAND SHIFT mode.

Diagnostic Trouble Codes & Freeze Frames

While the ignition is on, the TCM diagnoses the system for faults. The extent of the diagnostic capability at any particular time depends on the prevailing operating conditions, e.g. it is not possible to check for a short circuit to earth if the circuit concerned is already at a low potential. If the TCM detects a fault with the transmission system, it will enter a default mode to prevent further damage to the transmission and allow the vehicle to be driven. When a fault is detected a Controller Area Network (CAN) message is sent from the TCM and is received by the instrument pack. The instrument pack illuminates the Malfunction Indicator Lamp (MIL) and displays TRANS. FAILSAFE in the message center. Some transmission faults may not illuminate the MIL or display a fault message, but the driver may notice a reduction in shift quality.

The diagnostic socket allows the exchange of information between the various control modules on the bus systems and a diagnostic tool using Keyword 2000 protocol. The information is communicated to the socket via a diagnostic ISO9141 K Line. This allows the retrieval of diagnostic information.

The TCM uses a P code strategy, which stores industry standard and Land Rover specific Diagnostic Trouble Codes (DTC) relating to faults.

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

INPUT & OUTPUT SIGNALS

TRANSMISSION CONTROL MODULE

The TCM performs ten self-test integrity diagnostics on its internal hardware and software to check for faults, a fault is detected if

1. The engine speed is greater than 1408 RPM and the battery supply is less than 5 volts or battery supply is greater than 9 volts but less than 16 volts. This indicates a permanent voltage supply fault.
2. A CAN signal of a non-valid level has been received.
3. The ignition is on and the battery supply is greater than 9 volts but no CAN messages have been received by the TCM for 0.1 seconds.
4. The ignition is on but invalid CAN signals have been received.
5. The rationality check of the throttle position information has detected an invalid signal.
6. The calculated Electrically Erasable Programmable Read Only Memory (EEPROM) checksum does not match the stored checksum.
7. The shift solenoid and the pressure solenoid voltage are greater than the battery voltage minus 1 volt, while the supply is active.
8. The shift solenoid and the pressure solenoid voltage are less than 2.5 volts, while the supply is active.
9. The shift solenoid and the pressure solenoid voltage are less than 30% of the battery voltage, while the supply is active.
10. The shift solenoid and the pressure solenoid voltage are greater than or equal to 2.5 volts, while the supply is inactive.

For description of transmission control module fault enabling conditions (Scheme 53)or (Scheme 54).

Scheme 53

Scheme 54

TORQUE CONVERTER CLUTCH

An electronic pressure regulating solenoid, which is controlled by the TCM, hydraulically controls the Torque Converter Clutch (TCC). This allows the torque converter to have three states of operation as follows

1. Fully engaged.
2. Controlled slip variable engagement.
3. Fully disengaged.

Two hydraulic spool valves located in the valve block control the TCC. These valves are actuated by pilot pressure supplied via a solenoid valve, which is also located in the valve block. The solenoid valve is operated by Pulse Width Modulation (PWM) signals from the TCM to give full, partial or no lock-up of the TCC.

There is a function check of the TCC solenoid, an error is detected if the enabling conditions are satisfied and the engine speed minus the input shaft speed is greater than 80 RPM. (Scheme 55)

Scheme 55

ELECTRONIC PRESSURE REGULATOR SOLENOIDS

Five Electronic Pressure Regulator Solenoids are located in the valve block. The solenoids convert the electrical signals into hydraulic control pressure proportional to the signal to actuate the spool valves for precise transmission operation. Solenoid 4 is used for pressure regulation for the TCC.

Solenoid 1 supplies a lower control pressure as the signal amperage increases. The solenoid is a normally closed regulating flow solenoid valve and regulates the main line pressure. The solenoid is used for adaptive pressure control. The TCM monitors engine load and clutch slip and varies the solenoid duty cycle accordingly.

Solenoids 2, 3 and 5 supply a higher control pressure as the signal amperage increases. The solenoids are normally open solenoids regulating flow solenoid valves. The solenoids are used to regulate the supply of fluid pressure for clutch application during overlap up and down shifts of gears 2-3, 3-4 and 4-5. The TCM operates the solenoids using a PWM earth proportional to the required increasing or decreasing clutch pressures.

There are three diagnostic checks on each solenoid, a fault it detected if

1. The measured current is less than 200 mA and this current minus the calculated current is greater than 150 mA. Or, the measured current is greater than 200 mA and this current minus the calculated current is greater than 1000 mA.
2. A short circuit to battery positive has been detected.
3. A short circuit to ground has been detected.

A global diagnostic also takes place, where a fault is detected if the absolute sum of the current of all five solenoids minus the sum of each solenoid current is greater than 0.15 A. For fault enabling conditions (Scheme 56)or (Scheme 57).

Scheme 56

Scheme 57

SHIFT SOLENOID VALVES

Three Shift Solenoid Valves are located in the valve block. The TCM controls the solenoids and converts electrical signals into hydraulic control signals to control clutch application.

The shift solenoids (A, B and C) are normally closed, on/off solenoids, which are controlled by the TCM switching the solenoid to earth. The TCM also supplies power to solenoids. The TCM energizes the solenoids in a programmed sequence for clutch application for gear ratio changes and shift control.

There are four diagnostic checks for each solenoid, an error is detected if

1. The solenoid voltage is greater than 1V but less than 1.44V with the solenoid under current.
2. The solenoid voltage is greater than 0.85V but less than 1.44V with the solenoid not under current. This indicates a short circuit to battery positive condition.
3. The solenoid voltage is greater than 0V but less than 0.35V with the solenoid not under current. This indicates a short circuit to ground condition.
4. The solenoid voltage is greater than 0.35V but less than 0.85V with the solenoid not under current. This indicates an open circuit condition.

For fault enabling conditions (Scheme 58)

Scheme 58

TURBINE SHAFT SPEED SENSOR

The turbine shaft speed sensor is monitored by the TCM to calculate the slip of the TCC and internal clutch slip. This allows the TCM to accurately control the slip timing during shifts and adjust clutch application or release pressure for overlap shift control.

The turbine shaft speed sensor is located in the main casing and secured with a screw. The sensor monitors turbine speed from a toothed target wheel on the outer diameter of clutch 'B' housing. As the teeth of the target wheel pass the sensor tip, a change in the magnetic field of the sensor occurs and generates an AC pulse in the sensor field winding. The pulse is passed on the negative (ground) wire to the TCM, which calculates the rotational speed. The AC pulse generated is proportional to the rotational speed of the target wheel. The TCM measures the peak-to-peak outputs of the AC waveform to calculate the rotational speed being measured.

There are two diagnostic checks on the turbine shaft speed sensor, a fault is detected if

1. The enabling conditions are satisfied and the turbine shaft speed sensor indicates a speed of 0 RPM.
2. The turbine shaft speed sensor indicates a speed of greater than 6800 RPM.

For fault enabling conditions (Scheme 59)

Scheme 59

OUTPUT SHAFT SPEED SENSOR (2003-04 Model Years)

The output shaft speed is monitored by the TCM and compared to engine speed signals received on the CAN from the ECM. Using the comparison of the two signals the TCM calculates the transmission slip ratio for plausibility and maintains adaptive pressure control.

The output shaft speed sensor is located at the rear of the main casing and secured with a screw. The sensor monitors the output shaft speed from a toothed target wheel, which is an integral part of the park lock gear. As the teeth of the target wheel pass the sensor tip, a change in the magnetic field of the sensor occurs and generates an AC pulse in the sensor field winding. The pulse is passed on the negative (ground) wire to the TCM, which calculates the rotational speed. The AC pulse generated is proportional to the rotational speed of the target wheel. The TCM measures the peak-to-peak outputs of the AC waveform to calculate the rotational speed being measured.

There are four rationality checks on the output shaft speed sensor/gear ratio, a fault is detected if

1. The output shaft speed is greater than 7800 RPM or the output shaft speed minus wheel speed multiplied by the rear axle ratio changes by more than 1000 RPM.
2. The enabling conditions are satisfied and the output shaft speed is 0 RPM while the wheel speed is greater than 120 RPM.
3. The enabling conditions are satisfied and the turbine shaft speed minus the output shaft speed as a function of gear ratio changes by more than 5%.
4. The output speed, either calculated from the output shaft speed sensor or the rear wheel speed, is less than 255 RPM with a turbine shaft speed of greater than 1696 RPM while the vehicle is in drive.

For fault enabling conditions (Scheme 60)and (Scheme 61).

Scheme 60

Scheme 61

OUTPUT SHAFT SPEED SENSOR (2005 Model Year)

The output shaft speed is monitored by the TCM and compared to engine speed signals received on the CAN from the ECM. Using the comparison of the two signals the TCM calculates the transmission slip ratio for plausibility and maintains adaptive pressure control.

The output shaft speed sensor is located at the rear of the main casing and secured with a screw. The sensor monitors the output shaft speed from a toothed target wheel, which is an integral part of the park lock gear. As the teeth of the target wheel pass the sensor tip, a change in the magnetic field of the sensor occurs and generates an AC pulse in the sensor field winding. The pulse is passed on the negative (ground) wire to the TCM, which calculates the rotational speed. The AC pulse generated is proportional to the rotational speed of the target wheel. The TCM measures the peak-to-peak outputs of the AC waveform to calculate the rotational speed being measured.

There are three rationality checks on the output shaft speed sensor/gear ratio, a fault is detected if

1. Wheel speed is greater than 400 RPM and the output shaft speed is greater than 8160 RPM or the output shaft speed minus wheel speed multiplied by the rear axle ratio changes by more than 1500 RPM.
2. The enabling conditions are satisfied and the output shaft speed is less than 160 RPM or the wheel speed multiplied by the rear axle ratio is less than 160 RPM.
3. The enabling conditions are satisfied and the input shaft speed minus the output shaft speed as a function of gear ratio changes by more than 5%.

For fault enabling conditions (Scheme 62)and (Scheme 63).

Scheme 62

Scheme 63

POSITION SWITCH (2003-04 Model Year)

The position switch is located externally on the right hand side of the transmission. The switch is located on the selector shaft and secured to the main casing with screws. A protective cover is also fitted over the switch to prevent impact damage. The switch rotates with the selector shaft, moving the switch contacts to correspond to the selected program. The switch provides signals that allow the TCM to monitor the position of the manual selector spool valve and the selected drive program.

The switch is connected via an integral harness and multiplug on five wires to the TCM. One of the wires supplies a 12V supply to the switch. The remaining wires are connected to the TCM. When the transmission selector lever is moved to the selected position, one or more of the contacts within the switch are made, completing a circuit back to the TCM. From the switch contacts that are made, the TCM determines which selection is required and responds accordingly.

The position switch is continually checked for invalid codes i.e. the combination of switch contacts made indicating a non-existent gear range.

For fault enabling conditions (Scheme 64)

Scheme 64

INHIBITOR SWITCH (2005 Model Year)

The inhibitor switch is located externally on the right hand side of the transmission. The switch is located on the selector shaft and secured to the main casing with screws. A protective cover is also fitted over the switch to prevent impact damage. The switch rotates with the selector shaft, moving the switch contacts to correspond to the selected program. The switch provides signals that allow the TCM to monitor the position of the manual selector spool valve and the selected drive program.

The switch is connected via an integral harness and multiplug on five wires to the TCM. One of the wires supplies a 12V supply to the switch. The remaining wires are connected to the TCM. When the transmission selector lever is moved to the selected position, one or more of the contacts within the switch are made, completing a circuit back to the TCM. From the switch contacts that are made, the TCM determines which selection is required and responds accordingly.

There are two diagnostic checks of the Inhibitor switch, an error is detected if

1. The ignition supply is greater than 9V and an incorrect position code has been received.
2. The ignition supply is greater than 9V the engine is cranking and the position code does not indicate a park or neutral state.

For fault enabling conditions (Scheme 65)

Scheme 65

The shift interlock solenoid is located at the front of the selector lever assembly. The selector lever is connected to a locking plate that has two holes that correspond to the Park (P) and Neutral (N) positions. When the ignition is on or the engine is running, the solenoid is energized by the TCM when the selector lever is in the Park or Neutral positions. When energized, the solenoid ejects a pin that engages in the locking plate preventing the lever from being moved.

When the footbrake is applied, a signal from a brake switch is passed to the TCM that de-energizes the solenoid allowing the lever to be moved from the Park or Neutral position. This prevents the selector from being moved to the Drive or Reverse position unintentionally and the application of the brakes also prevents the vehicle CREEPING when the gear is engaged.

Movement of the selector lever from the Park or Neutral positions is also prevented if the TCM senses that the engine speed is above 2500 rev/min, even if the brake pedal is depressed.

There are four diagnostic checks for each shift solenoid, an error is detected if

1. The shift solenoid voltage is greater than 1V but less than 1.44V with the solenoid under current.
2. The shift solenoid voltage is greater than 0.85V but less than 1.44V with the solenoid not under current.
3. The shift solenoid voltage is greater than 1.44V but less than 5V with the solenoid under current. This indicates a short to battery positive condition.
4. The shift solenoid voltage is greater than 0V but less than 0.35V with the solenoid not under current. This indicates a short to ground condition.
5. The shift solenoid voltage is greater than 0.35V but less than 0.85V with the solenoid not under current. This indicates an open circuit condition.
6. A rationality check monitors 2/3 and 3/4 shifts for a lack of change to the input speed or a too great change to input speed.

For fault enabling conditions (Scheme 66)or (Scheme 67).

Scheme 66

Scheme 67

HIGH/LOW RANGE SELECTOR SWITCH (2003-04 Model Year)

The high/low range switch is located on the selector lever cover, on the right hand side of the selector lever. The switch can be identified by the high/low range legend graphic and the switch lever is colored white. High or low range can be selected using this switch providing the vehicle speed is within defined limits and the gear selector lever is in the neutral position.

There are two diagnostic checks for the high/low range selector switch, an error is detected if

1. An invalid code is received from the selector switch.
2. The TCM does not receive a CAN signal within the predefined time period.

For fault enabling conditions (Scheme 68)

Scheme 68

HIGH/LOW RANGE SELECTOR SWITCH (2005 Model Year)

The high/low range switch is located on the selector lever cover, on the right hand side of the selector lever. The switch can be identified by the high/low range legend graphic and the switch lever is colored white. High or low range can be selected using this switch providing the vehicle speed is within defined limits and the gear selector lever is in the neutral position.

There is one diagnostic check for the high/low range selector switch, an error is detected if an invalid code is received from the selector switch.

Note. This diagnostic is also reported by the ECM as P2772.

For fault enabling conditions (Scheme 69)

Scheme 69

TRANSMISSION FLUID TEMPERATURE SENSOR

The TFT sensor is located inside the wiring harness in the fluid pan and is connected to the TCM with two wires. The sensor is a Positive Temperature Co-efficient sensor, containing semi-conductor material, which increases its resistance as the temperature increases.

The sensor receives a predetermined current from the TCM on one of the wires and is connected to earth via the TCM on the second wire. The TCM measures the returned voltage and using this information calculates the TFT.

In the case of low fluid temperatures, the TCM prohibits TCC lock-up to promote faster fluid warm up.

In the case of high fluid temperatures, the TCM increases the converter lock-up control and modifies the shift program to reduce fluid temperature.

If the sensor fails, the TCM uses a programmed default temperature value. The default value is derived from the ECT sensor and received on the CAN from the ECM.

There are six diagnostic checks for the TFT sensor, an error is detected if

1. The voltage at the positive connection to the sensor is greater than 4.5V and the voltage at the negative connection of the sensor is less than 0.5V. This indicates an open circuit condition.
2. The voltage at the positive connection of the sensor is greater than 4.5V and the voltage at the negative connection of the sensor is greater than 0.5V. This indicates a short to battery voltage condition.
3. The voltage at the positive connection to the sensor is less than 4.5V and the voltage at the negative connection of the sensor is less than 0.5V. This indicates a short to ground condition.
4. The voltage at the positive connection of the sensor is greater than 2.3V and less than 2.7V and the voltage at the negative connection of the sensor is greater than 2.3V and less than 2.7V. This indicates a short circuit across the sensor.
5. The temperature rise between readings is greater than 10°C (50°F).
6. The temperature rise since engine start is less than 5°C (41°F).

For fault enabling conditions (Scheme 70)or (Scheme 71).

Scheme 70

Scheme 71

TRANSMISSION STALL SPEED (2005 Model Year)

This monitor detects failures with either the output speed sensor or the transmission unit itself.

The monitor checks for excessive turbine (input) speed with very low output speeds, indicating a very high level of slip throughout the transmission or a speed sensor fault. The monitor runs continuously whenever the transmission has not shifted for 200ms and the output speed is below 255 RPM. If this monitor detects a fault the TCM will log a DTC and invoke its electrical limp home mode.

For fault enabling conditions (Scheme 72)

Scheme 72

Description

1. DTC P0702 Internal FET fault: Open circuit
2. DTC P0702 Internal FET fault: Short circuit to battery
3. DTC P0702 Internal FET fault: Short circuit to ground

Possible Causes

1. Electronic Automatic Transmission ECU. See step 1 under CHECK.

Check

1. Electronic Automatic Transmission ECU No detail available for this fault.

1. DTC P0705 Gear Switch Fault: Plausibility Fault

1. Connectors C1835, C1452. See step 1 under CHECK.
2. Circuit integrity C1835/34 (B) - C1452/1 (B). See step 2 under CHECK.
3. Circuit integrity C1835/24 (O) - C1452/2 (O). See step 3 under CHECK.
4. Circuit integrity C1835/14 (P) - C1452/3 (P). See step 4 under CHECK.
5. Circuit integrity C1835/4 (Y) - C1452/4 (Y). See step 5 under CHECK.
6. Circuit integrity C1835/31 (G) - C1452/5 (G). See step 6 under CHECK.
7. Gearbox Gear Selector Switch. See step 7 under CHECK.
8. Electronic Automatic Transmission ECU. See step 8 under CHECK.

1. CONNECTOR Connectors C1835, C1452. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/34 (B) - C1452/1 (B). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/24 (O) - C1452/2 (O). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. CIRCUIT_INTEGRITY Circuit integrity C1835/14 (P) - C1452/3 (P). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
5. CIRCUIT_INTEGRITY Circuit integrity C1835/4 (Y) - C1452/4 (Y). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
6. CIRCUIT_INTEGRITY Circuit integrity C1835/31 (G) - C1452/5 (G). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
7. Gearbox Gear Selector Switch Check the state of each gear switch input against each gear position against the following table. Each entry in the table states, for each gear position, the expected connectivity between the common line, C1452/5, and each gear switch line. See «GEARBOX GEAR SELECTOR SWITCH TESTING»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission) table. GEARBOX GEAR SELECTOR SWITCH TESTING (1) Gear Switch Line/Connector/Pin No. P R N D L1/C1452/1 SC OC SC OC L2/C1452/2 SC OC SC OC L3/C1452/3 SC SC OC OC L4/C1452/4 OC SC SC SC (1) PASS VALUES: Short circuit (SC) less than 2.0 Ohms. Open circuit (OC) greater than 2.0 Ohms.
8. Electronic Automatic Transmission ECU No detail available for this fault.

1. DTC P0710 Gearbox Oil Temperature Sensor Fault: Plausibility Fault
2. DTC P0711 Gearbox Oil Temperature Sensor Fault: General Fault
3. DTC P0711 Gearbox Oil Temperature Sensor Fault: Open Circuit
4. DTC P0712 Gearbox Oil Temperature Sensor Fault: Short Circuit To Ground
5. DTC P0713 Gearbox Oil Temperature Sensor Fault: Short Circuit To Battery

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/22 (BR) - C0244/13 (BR). See step 2 under CHECK.
3. Circuit integrity C1835/12 (WR) - C0244/14 (WR). See step 3 under CHECK.
4. Gearbox Oil Temperature Sensor. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/22 (BR) - C0244/13 (BR). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/12 (WR) - C0244/14 (WR). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Oil Temperature Sensor No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. DTC P0711 Gearbox Temperature Monitor Fault: General Fault

1. Severe overload of vehicle. See step 1 under CHECK.
2. Major gearbox internal fault. See step 2 under CHECK.
3. Gearbox oil overfill. See step 3 under CHECK.

1. Severe Overload Of Vehicle No detail available for this fault.
2. Major Gearbox Internal Fault No detail available for this fault.
3. Gearbox Oil Overfill No detail available for this fault.

1. P0715 Turbine Speed Sensor Fault: Plausibility Fault
2. P0716 Turbine Speed Sensor Fault: Value Is Too High

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/23 (U) - C0244/5 (U). See step 2 under CHECK.
3. Circuit integrity C1835/33 (S) - C0244/6 (S). See step 3 under CHECK.
4. Gearbox Turbine Speed Sensor. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/23 (U) - C0244/5 (U). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/33 (S) - C0244/6 (S). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Turbine Speed Sensor No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P0720 Output Shaft Speed Sensor Fault: Plausibility Fault
2. P0721 Output Shaft Speed Sensor Fault: Value Is Too High

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/13 (W) - C0244/1 (W). See step 2 under CHECK.
3. Circuit integrity C1835/3 (N) - C0244/10 (N). See step 3 under CHECK.
4. Gearbox Output Shaft Speed Sensor. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/13 (W) - C0244/1 (W). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/3 (N) - C0244/10 (N). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Output Shaft Speed Sensor No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P0730 Symptom Gear Monitor Fault: Plausibility Fault

1. Gearbox mechanical fault. See step 1 under CHECK.
2. CAN bus. See step 2 under CHECK.

1. Gearbox Mechanical Fault No detail available for this fault. See «BOSCH EAT FAULT DTC P0730 - ELECTRONIC AUTOMATIC TRANSMISSION STALL SPEED FAULT»(/land-rover/range-rover/iii-2002-2005/remont/automatic-trans/#diagnosis-zf5hp24-automatic-transmission) .
2. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P0730 Stall speed fault: Plausibility fault.

1. Transmission Damage (Defective Clutch). See step 1 under CHECK.

1. Transmission Damage (Defective Clutch) No detail available for this fault.

1. P0731 Gear Monitor 1 Fault: Plausibility Fault

1. Gearbox mechanical fault. See step 1 under CHECK.
2. CAN bus. See step 2 under CHECK.

1. Gearbox Mechanical Fault No detail available for this fault.
2. CAN Bus Fault in CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P0732 Gear Monitor 2 Fault: Plausibility Fault

1. Gearbox mechanical fault. See step 1 under CHECK.
2. CAN bus. See step 2 under CHECK.

1. Gearbox Mechanical Fault No detail available for this fault.
2. CAN Bus Fault in CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. DTC P0733 Gear Monitor 3 Fault: Plausibility Fault

1. Gearbox mechanical fault. See step 1 under CHECK.
2. CAN bus. See step 2 under CHECK.

1. Gearbox Mechanical Fault No detail available for this fault.
2. CAN Bus Fault in CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P0734 Gear Monitor 4 Fault: Plausibility Fault

1. Gearbox mechanical fault. See step 1 under CHECK.
2. CAN bus. See step 2 under CHECK.

1. Gearbox Mechanical Fault No detail available for this fault.
2. CAN Bus Fault in CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P0735 Gear Monitor 5 Fault: Plausibility Fault

1. Gearbox mechanical fault. See step 1 under CHECK.
2. CAN bus. See step 2 under CHECK.

1. Gearbox Mechanical Fault No detail available for this fault.
2. CAN Bus Fault in CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P0740 Pressure line solenoid 4 fault: Plausibility fault.
2. P0743 Pressure line solenoid 4 fault: General fault.
3. P0743 Pressure line solenoid 4 fault: Short circuit to battery.
4. P0743 Pressure line solenoid 4 fault: Short circuit to ground or open circuit.

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/11 (P) - C0244/12 (P). See step 2 under CHECK.
3. Circuit integrity C1835/7 (TB) - C0244/11 (TB). See step 3 under CHECK.
4. Gearbox Pressure Line Solenoid (EDS) 4. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/11 (P) - C0244/12 (P). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/7 (TB) - C0244/11 (TB). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Pressure Line Solenoid (EDS) 4 No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P0741 Mechanical Torque Converter Monitor Fault: Plausibility Fault.

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/23 (U) - C0244/5 (U). See step 2 under CHECK.
3. Circuit integrity C1835/33 (S) - C0244/6 (S). See step 3 under CHECK.
4. Gearbox Turbine Speed Sensor. See step 4 under CHECK.
5. Torque Converter Clutch. See step 5 under CHECK.
6. Electronic Automatic Transmission ECU. See step 6 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/23 (U) - C0244/5 (U). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/33 (S) - C0244/6 (S). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Turbine Speed Sensor No detail available for this fault.
5. Torque Converter Clutch No detail available for this fault.
6. Electronic Automatic Transmission ECU No detail available for this fault.

1. P0745 Pressure Line Solenoid 1 Fault: Plausibility Fault
2. P0748 Pressure Line Solenoid 1 Fault: General Fault
3. P0748 Pressure Line Solenoid 1 Fault: Short Circuit To Battery
4. P0748 Pressure Line Solenoid 1 Fault: Short Circuit To Ground Or Open Circuit

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/11 (P) - C0244/12 (P). See step 2 under CHECK.
3. Circuit integrity C1835/28 (R) - C0244/2 (R). See step 3 under CHECK.
4. Gearbox Pressure Line Solenoid (EDS) 1. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/11 (P) - C0244/12 (P). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/28 (R) - C0244/2 (R). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Pressure Line Solenoid (EDS) 1 No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P0750 Shift Solenoid 1 Fault: Plausibility Fault
2. P0751 Shift Solenoid 1 Fault: Open Circuit
3. P0752 Shift Solenoid 1 Fault: Short Circuit To Ground
4. P0753 Shift Solenoid 1 Fault: Short Circuit To Battery

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/21 (YU) - C0244/16 (YU). See step 2 under CHECK.
3. Circuit integrity C1835/38 (O) - C0244/8 (O). See step 3 under CHECK.
4. Gearbox Shift Solenoid (MV) 1. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/21 (YU) - C0244/16 (YU). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/38 (O) - C0244/8 (O). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Shift Solenoid (MV) 1 No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P0755 Shift Solenoid 2 Fault: Plausibility Fault
2. P0756 Shift Solenoid 2 Fault: Open Circuit
3. P0757 Shift Solenoid 2 Fault: Short Circuit To Ground
4. P0758 Shift Solenoid 2 Fault: Short Circuit To Battery

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/21 (YU) - C0244/16 (YU). See step 2 under CHECK.
3. Circuit integrity C1835/26 (G) - C0244/9 (G). See step 3 under CHECK.
4. Gearbox: Shift Solenoid (MV) 2. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/21 (YU) - C0244/16 (YU). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/26 (G) - C0244/9 (G). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox: Shift Solenoid (MV) 2 No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P0760 Shift Solenoid 3 Fault: Plausibility Fault
2. P0761 Shift Solenoid 3 Fault: Open Circuit
3. P0762 Shift Solenoid 3 Fault: Short Circuit To Ground
4. P0763 Shift Solenoid 3 Fault: Short Circuit To Battery

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/21 (YU) - C0244/16 (YU). See step 2 under CHECK.
3. Circuit integrity C1835/16 (Y) - C0244/4 (Y). See step 3 under CHECK.
4. Gearbox Shift Solenoid (MV) 3. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/21 (YU) - C0244/16 (YU). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/16 (Y) - C0244/4 (Y). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Shift Solenoid (MV) 3 No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P0775 Pressure Line Solenoid 2 Fault: Plausibility Fault
2. P0778 Pressure Line Solenoid 2 Fault: General Fault
3. P0778 Pressure Line Solenoid 2 Fault: Short Circuit To Battery
4. P0778 Pressure Line Solenoid 2 Fault: Short Circuit To Ground Or Open Circuit

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/11 (P) - C0244/12 (P). See step 2 under CHECK.
3. Circuit integrity C1835/27 (B) - C0244/3 (B). See step 3 under CHECK.
4. Gearbox Pressure Line Solenoid (EDS) 2. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/11 (P) - C0244/12 (P). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/27 (B) - C0244/3 (B). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Pressure Line Solenoid (EDS) 2 No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P0780 Controlled Load Transfer Fault: Value Has Not Changed
2. P0780 Controlled Load Transfer Fault: Value Is Too High

1. Gearbox mechanical fault. See step 1 under CHECK.
2. CAN bus. See step 2 under CHECK.

1. Gearbox Mechanical Fault No detail available for this fault.
2. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P0782 Controlled Load Transfer 2/3 Fault: Value Has Not Changed
2. P0782 Controlled Load Transfer 2/3 Fault: Value Is Too High

1. Gearbox mechanical fault. See step 1 under CHECK.
2. CAN bus. See step 2 under CHECK.

1. Gearbox Mechanical Fault No detail available for this fault.
2. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P0783 Controlled Load Transfer 3/4 Fault: Value Has Not Changed
2. P0783 Controlled Load Transfer 3/4 Fault: Value Is Too High

1. Gearbox mechanical fault. See step 1 under CHECK.
2. CAN bus. See step 2 under CHECK.

1. Gearbox mechanical fault No detail available for this fault.
2. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P0795 Pressure Line Solenoid 3 Fault: Plausibility Fault
2. P0798 Pressure Line Solenoid 3 Fault: General Fault
3. P0798 Pressure Line Solenoid 3 Fault: Short Circuit To Battery
4. P0798 Pressure Line Solenoid 3 Fault: Short Circuit To Ground Or Open Circuit

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/11 (P) - C0244/12 (P). See step 2 under CHECK.
3. Circuit integrity C1835/17 (K) - C0244/7 (K). See step 3 under CHECK.
4. Gearbox Pressure Line Solenoid (EDS) 3. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins
2. CIRCUIT_INTEGRITY Circuit integrity C1835/11 (P) - C0244/12 (P). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/17 (K) - C0244/7 (K). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Pressure Line Solenoid (EDS) 3 No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1601 Internal Checksum Error: Plausibility Fault

1. Electronic Automatic Transmission ECU. See step 1 under CHECK.

1. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1604 Internal Watchdog Fault: General Fault

1. Electronic Automatic Transmission ECU. See step 1 under CHECK.

1. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1605 Internal EEPROM Fault: General Fault

1. Electronic Automatic Transmission ECU. See step 1 under CHECK.

1. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1646 CAN Bus Missing Node - Electronic Automatic Transmission ECU: Last Occurrence - Signal Fault

1. Circuit integrity to C0331/36 (YB). See step 1 under CHECK.
2. Circuit integrity to C0331/37 (YN). See step 2 under CHECK.
3. Connector C0331. See step 3 under CHECK.
4. Electronic Automatic Transmission ECM. See step 4 under CHECK.
5. V8 Engine Management System ECM. See step 5 under CHECK.

1. CIRCUIT_INTEGRITY Circuit integrity to C0331/36 (YB). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
2. CIRCUIT_INTEGRITY Circuit integrity to C0331/37 (YN). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CONNECTOR Connector C0331. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
4. Electronic Automatic Transmission ECM No detail available for this fault.
5. V8 Engine Management System ECM No detail available for this fault.

1. P1700 CAN Bus Transfer Box Range Error: Plausibility Fault

1. CAN Bus. See step 1 under CHECK.

1. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P1700 Transfer Box Controller Signal Fault: Last Occurrence - Plausibility

1. Connector C0331, C0862. See step 1 under CHECK.
2. Transfer Box ECU. See step 2 under CHECK.

1. CONNECTOR Connector C0331, C0862. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins
2. Transfer Box ECU There is a transfer box signal fault. Check the transfer box system for faults. Use Real Time Monitoring to monitor the transfer box range change signal. This fault is raised if the selected transfer box range (low or high) is selected and is different from the current range for more than one minute.

1. P1710 Battery Feed KI87 Fault: General Fault
2. P1710 Battery Feed KI87 Fault: Plausibility Fault

1. Engine fusebox Fuse 1. See step 1 under CHECK.
2. Connectors C0932, C0570. See step 2 under CHECK.
3. Circuit integrity C0932/8 (RU) - C0570/2 (RU). See step 3 under CHECK.
4. Circuit integrity C0932/9 (RU) - C0570/2 (RU). See step 4 under CHECK.
5. Circuit integrity C0932/4 (N) - Ground (N). See step 5 under CHECK.
6. Circuit integrity C0932/5 (N) - Ground (N). See step 6 under CHECK.
7. Circuit integrity C0932/6 (N) - Ground (N). See step 7 under CHECK.
8. Electronic Automatic Transmission ECU. See step 8 under CHECK.

1. POWER_DISTRIBUTION Engine fusebox Fuse 1. 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. Eg Check if other circuits fed by the same fuse are also experiencing problems.
2. CONNECTOR Connectors C0932, C0570. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
3. CIRCUIT_INTEGRITY Circuit integrity C0932/8 (RU) - C0570/2 (RU). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. CIRCUIT_INTEGRITY Circuit integrity C0932/9 (RU) - C0570/2 (RU). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
5. CIRCUIT_INTEGRITY Circuit integrity C0932/4 (N) - Ground (N). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
6. CIRCUIT_INTEGRITY Circuit integrity C0932/5 (N) - Ground (N). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
7. CIRCUIT_INTEGRITY Circuit integrity C0932/6 (N) - Ground (N). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
8. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1711 Battery Feed KI30 Fault: Plausibility Fault

1. Possible causes: Engine fusebox Fuse 4. See step 1 under CHECK.
2. Connectors C0932, C0570. See step 2 under CHECK.
3. Circuit integrity C0932/7 (R) - C0570/8 (R). See step 3 under CHECK.
4. Electronic Automatic Transmission ECU. See step 4 under CHECK.

1. POWER_DISTRIBUTION Engine fusebox Fuse 4. 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. Eg Check if other circuits fed by the same fuse are also experiencing problems.
2. CONNECTOR Connectors C0932, C0570. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
3. CIRCUIT_INTEGRITY Circuit integrity C0932/7 (R) - C0570/8 (R). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1743 Pressure Line Solenoid 5 Fault: General Fault
2. P1743 Pressure Line Solenoid 5 Fault: Short Circuit To Battery
3. P1743 Pressure Line Solenoid 5 Fault: Short Circuit To Ground Or Open Circuit
4. P1745 Pressure Line Solenoid 5 Fault: Plausibility Fault

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/11 (P) - C0244/12 (P). See step 2 under CHECK.
3. Circuit integrity C1835/6 (YR) - C0244/15 (YR). See step 3 under CHECK.
4. Gearbox Pressure Line Solenoid (EDS) 5. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/11 (P) - C0244/12 (P). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C1835/6 (YR) - C0244/15 (YR). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Gearbox Pressure Line Solenoid (EDS) 5 No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1748 Pressure Line Solenoid Total Current Fault: Plausibility Fault

1. Connectors C1835, C0244. See step 1 under CHECK.
2. Circuit integrity C1835/11 (P) - C0244/12 (P). See step 2 under CHECK.
3. Gearbox Pressure Line Solenoids. See step 3 under CHECK.
4. Electronic Automatic Transmission ECU. See step 4 under CHECK.

1. CONNECTOR Connectors C1835, C0244. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C1835/11 (P) - C0244/12 (P). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. Gearbox Pressure Line Solenoids No detail available for this fault.
4. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1789 Steptronic Fault: Plausibility Fault

1. Connectors C0193, C0685, C1664. See step 1 under CHECK.
2. Circuit integrity C0193/20 (UY) - C1664/2 (UY). See step 2 under CHECK.
3. Circuit integrity C0193/19 (US) - C1664/3 (US). See step 3 under CHECK.
4. Circuit integrity C0193/18 (WU) - C0685/3 (WU). See step 4 under CHECK.
5. Circuit integrity C0685/1 (WG) - C1664/4 (WG). See step 5 under CHECK.
6. Circuit integrity C1664/1 (NB) - Ground. See step 6 under CHECK.
7. Steptronic Switch. See step 7 under CHECK.
8. Transmission High/Low Switch. See step 8 under CHECK.
9. Electronic Automatic Transmission ECU. See step 9 under CHECK.

1. CONNECTOR Connectors C0193, C0685, C1664. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C0193/20 (UY) - C1664/2 (UY). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C0193/19 (US) - C1664/3 (US). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. CIRCUIT_INTEGRITY Circuit integrity C0193/18 (WU) - C0685/3 (WU). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
5. CIRCUIT_INTEGRITY Circuit integrity C0685/1 (WG) - C1664/4 (WG). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
6. CIRCUIT_INTEGRITY Circuit integrity C1664/1 (NB) - Ground. Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
7. Steptronic Switch Check for open/short circuit with switch open/closed.
8. Transmission High/Low Switch Check for open/short circuit with switch open/closed.
9. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1825 Shift Solenoid Shift Lock Fault: Open Circuit
2. P1825 Shift Solenoid Shift Lock Fault: Plausibility Fault
3. P1825 Shift Solenoid Shift Lock Fault: Short Circuit To Battery
4. P1825 Shift Solenoid Shift Lock Fault: Short Circuit To Ground

1. Connectors C0193, C0673. See step 1 under CHECK.
2. Circuit integrity C0193/2 (BP) - C0673/1 (BP). See step 2 under CHECK.
3. Circuit integrity C0193/1 (NP) - C0673/3 (NP). See step 3 under CHECK.
4. Shift Interlock Solenoid. See step 4 under CHECK.
5. Electronic Automatic Transmission ECU. See step 5 under CHECK.

1. CONNECTOR Connectors C0193, C0673. Check for connector not correctly latched, backed out pins, damaged pins, corroded pins.
2. CIRCUIT_INTEGRITY Circuit integrity C0193/2 (BP) - C0673/1 (BP). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
3. CIRCUIT_INTEGRITY Circuit integrity C0193/1 (NP) - C0673/3 (NP). Check for open circuit, short circuit to ground, supply or other circuit, damaged or unlatched connector, intermediate connectors or headers.
4. Shift Interlock Solenoid No detail available for this fault.
5. Electronic Automatic Transmission ECU No detail available for this fault.

1. P1840 CAN Bus Monitor Fault: Plausibility Fault

1. CAN Bus. See step 1 under CHECK.

1. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P1842 Can Bus Status Error: Plausibility Fault

1. CAN Bus. See step 1 under CHECK.

1. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P1843 Can Bus Transfer Box Timeout: Plausibility Fault

1. CAN Bus. See step 1 under CHECK.

1. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P1844 Can Bus Engine Management System Timeout: Plausibility Fault

1. CAN Bus. See step 1 under CHECK.

1. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P1845 Can Bus ABS Timeout: Plausibility Fault

1. CAN Bus. See step 1 under CHECK.

1. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P1884 CAN Bus Throttle Valve Signal Fault: Plausibility Fault

1. CAN Bus. See step 1 under CHECK.

1. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

1. P1885 CAN Bus Brake Signal Fault: Plausibility Fault

1. CAN Bus. See step 1 under CHECK.

1. CAN Bus Fault CAN bus. Check the following: Integrity of all CAN Bus connections. Look for similar faults in other ECUs on the CAN Bus. Look for faults in the originating ECU (if applicable), including intermittent supplies/ground faults. Refer to the CAN Bus wiring diagram.

WIRING DIAGRAMS

For 2003 Range Rover wiring diagram, see TRANSMISSION in SYSTEM WIRING DIAGRAMS article.

For 2004 Range Rover wiring diagram, see TRANSMISSION in SYSTEM WIRING DIAGRAMS article.

WIRE COLORS

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

WIRE COLOR CODES

See also:
• ONE-WAY FREE WHEEL CLUTCH
• TEMPERATURE SENSOR RESISTANCE VALUES
• NORMAL MODE
• SPORT MODE
• MANUAL (COMMANDSHIFT) MODE
• ENGINE WARM-UP MODE
• HDC MODE
• CRUISE MODE
• HILL MODE
• DEFAULT (LIMP HOME) MODE
• REVERSE LOCK-OUT MODE
• COOLING STRATEGY