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Note: Procedures described are for guidance only. Refer to vehicle manufacturer’s technical information for up-to-date procedures. HEVRA cannot take responsibility for injury, malfunction or accident.

Introduced in 2010 in Japan, and 2011 in the UK, the Nissan Leaf (which stands for Leading Environmentally-friendly Affordable Family car) is the most popular all-electric vehicle on Britain’s roads. With a distinctive bug-eyed appearance and finned headlamps to reduce wind noise, the combination of relatively low cost, reliability and Nissan’s dealer network has proved a hit with EV buyers. Many Leafs are bought new on PCP or Lease, with the fuel savings covering the monthly payments. In March 2013, Nissan brought Leaf manufacturing here to England, building the car on the Qashqai line and sharing the Sunderland factory with the Note and Juke models, with the high voltage batteries also made locally. At the same time, Nissan updated the car with a new black interior (early models were beige), improved battery, heating system, new trim designations (including a new cheaper ‘Visia’ model) and a foot-operated parking brake replacing the electric parking brake on all models. Early Japanese-built models, model code EM61, will have a VIN beginning with J, UK-built cars are model code EM57 and the VIN will start with S.

Under the bonnet, 2013-on (EM57) models are faced with the Power Distribution Module housing the on-board charger, DC-DC converter for 12v battery charging, air conditioning relays, DC charging relays and charging fuses (note the fuses should only blow in exceptional circumstances- to replace them involves discharging the high voltage system and removing the PDM cover which is held in place with sealant). Under the PDM lives the inverter, and beneath that the motor, reduction gear and differential. Early (EM61) models have just the motor and inverter underbonnet with the charger located in the rear of the vehicle.

BATTERY

The Leaf was launched with a 24kWh battery- this is the total capacity, and as with all traction batteries, the very top and bottom of the battery are not used, so the useable capacity is a little less. 2013 brought an updated battery of the same capacity but designed for reduced wear, and this does seem to be an improvement. From 2016 a 30kWh battery was available as an option, with the vast majority of buyers going for the larger version. 30KWh variants can be identified by their higher gross weight on the VIN plate (1970kg compared to 1945kg).

Unusually, the Leaf has no battery cooling system, but instead has battery cells that are designed to absorb heat without affecting their short-term or long-term health. This strategy seems to have worked well for Nissan in the UK and Northern Europe, although in hot parts of the US many Leafs have suffered from early battery degradation. Battery degradation on the Leaf is a normal part of ownership, although it happens slowly and gradually, with many cars over 100,000 miles covering significantly less miles per charge than when new, although still enough to make it a useable car for many drivers. The battery’s health can be checked from the driver’s seat using the battery capacity bars up the side of the battery charge gauge- 12 bars being the full quota and the first bar disappearing when the battery gets to around 85% state of health.

The lack of battery cooling system means the Leaf is one of few EVs on the market with a battery temperature gauge- as a rough rule of thumb expect three bars in winter, four in spring/autumn and five in summer, with driving and charging both increasing the temperature. Long trips with fast driving and rapid charging will result in higher readings, with 24kWh versions being able to dissipate heat a little better than the denser 30kWh battery. In the event that the battery temperature is too high, with no cooling system to check the only thing that can be done is check the three temperature sensors are reading correctly and allow the car to cool over a period of time. High battery temperatures will cause reduced motor power and reduced charging speeds, although only extreme use will cause these symptoms.

Battery ECU and System Main Relays are all located in the battery case, however opening the case will void the battery warranty.

CHARGING

The Leaf offers two charging options- a Type 1 connector for AC charging, and a CHAdeMO for rapid charging, rated to 3.3kW AC and 50kW DC respectively. A faster 6.6kW charger was available as an option, which of course needs a 32A supply and cable in order to make use of the higher speed. The charger on early models was behind the rear seats, which was moved under the bonnet for 2013 models. You can determine the charger fitted by using the trip computer buttons to cycle through the display in front of the driver. When the charging time is displayed, models with the optional faster charger will show different times for 3.3kW and 6.6kW supplies. The CHAdeMO DC charging connector was not standard on the “Visia” base model.

Pre-2016 models had an option to limit charging to 80%. If a customer complains that charging is not finishing this is the first thing to check (set within the touch screen menu by pressing ZeroEmission button). When rapid charging from less than 50% full, the charging will stop at 80% full unless restarted. This function was deleted with the 2013 update so later cars will charge from empty to full normally.

EM57 (2013-on) models have an electric release on the charging port, operated by holding the button in the car or on the key fob.

A charging timer is fitted on all models to allow the vehicle to charge at a convenient time or make use of off-peak electricity tariffs. The times are set through the touchscreen by pressing the ZeroEmission button. If just an end time is set, the vehicle will estimate the charging time and start at the required time to make sure the vehicle is charged by this time. The clock used is the same as the one displayed, so any error in the clock time will affect the charging timer. A timer bypass button is fitted to override the usual schedule if the vehicle needs to be charged straight away.

Three blue charging indicator lights are fitted on top of the dashboard. During charging, the first light will flash until the battery reaches approximately 1/3 full, at which point the first light will be on solid and the second light flash, and so on. Lights coming on alternately as if scrolling across means the charging cable is connected but charging has not started as the charging timer is set. If the third light is blinking when the charging cable is unplugged, this indicates the remote heater or air conditioning is operating, or the vehicle is topping up the 12v battery. The centre light on solid means the vehicle’s charging timer has been bypassed and the vehicle will charge as soon as the supply is connected.

The Leaf has an unusual gear selector between the front seats- little pad moves towards the driver for Drive, and towards the front for Reverse, with a little park button on top. To select Neutral, the selector just needs to be held to to the centre right for a second or so. The gear selector is entirely hall-effect with no physical switches- so attempting to clean it is probably a waste of time unless the movement is physically restricted by debris. Six sensors built into the selector all switch from 0v to 5v and the car uses this to determine the selector position. If the customer complains of a delay in selecting drive, check for fault P0705 which is an indicating of a hall-effect sensor not switching and may indicate a faulty selector assembly. The other issue if a customer says they cannot select gear is to make sure the car is actually on rather than just ignition on.

Moving the selector towards the D position when already in Drive will alternate between D and B (Brake) modes- with B offering a higher level of regenerative braking. D and B can be switched at any time, including when driving.

All Leafs use a proximity key with keyless entry and keyless starting. A blade can be withdrawn from the key for emergency use. There is also a backup transponder ring by the start button, so if the key is completely flat, the vehicle can be started by holding the key next to the start button when trying to start.

Acenta and Tekna models have a colour touchscreen with sat-nav as standard. In order for this and the audio system to function, the SD card must be present, and these are VIN specific so cannot be swapped between vehicles. The screen has a button at the bottom right- press to open or hold to adjust the angle it sits at. The SD card is visible when the screen is open.

CABIN HEATING & COOLING

All Leafs have air conditioning, driven by a high voltage DC compressor, and a PTC heater also driven by the high voltage system. The PTC (positive temperature coefficient) heater element increases in resistance as it warms, reducing the current flow. The PTC heater is also PWM controlled to reduce the heat as required. All Leafs have electronic climate control which aims to reduce wasteful use of the heater and air conditioning as well as improving passenger comfort. Cabin filter is in the heater box and accessed by removing the glovebox or reaching up behind it.

EM61 Models (2010-2013)
Between the nearside headlamp and the 12v battery is the majority of the heating system, consisting of the 5kW PTC heater (high voltage), header tank, and PWM-controlled 12v heater circulation pump. The pump pushes coolant through the PTC heater assembly, which contains four separate elements and its own control system, connected to the climate control ECU via a LIN network. From there it goes through a temperature sensor, into the heater matrix, header tank and then back to the pump inlet. Apart from the high voltage compressor, the air conditioning system is entirely conventional and is of the thermal expansion valve type.

EM57 Models (2013-2017)
2013-on models have a PTC heater directly heating the air in the heater box, and also use an air source heat pump to improve the efficiency of the heating system (not on “Visia” base model). This uses existing air conditioning components to pull heat from outside to warm the interior, effectively air conditioning in reverse. Switching on the heater should increase the A/C compressor current when looking in live data- if it does not then suspect low refrigerant or a system malfunction. The compressor is located under the bonnet where one might expect the cam pulleys to be on a combustion engined car, and is powered by the Power Distribution Module, not the inverter.

The heat pump functions as in the diagrams below. In cooling mode, the valve shown at the top of the diagram is open, which means the system functions as normal air conditioning system.

The valve closes when the system is in heating mode. The refrigerant flows in the same direction, but now there is a pressure drop, causing a temperature drop. This means the (now cold) refrigerant absorbs heat from the ambient air, and with the compressor increasing the pressure again, it can drop the heat inside the car.

 

 

 

 

 

 

 

Climate control can also be set by a timer on all models, and by an app on all models except Visia. It’s worth noting the desired temperature is not related to the current setting in the car, but it set via a separate menu within the touch screen. When plugged in, the car will draw power from the mains to keep the battery full, however on cars with the standard 3.3kW charger owners may notice a small drop in battery charge as the heater consumes more power than the charger can provide. The remote climate control will operate for two hours if plugged in, or 15 minutes when not plugged in. During remote climate control, the car will also charge the 12V battery.

ELECTRICAL SYSTEM

The Leaf unusually has a standard lead acid 12V battery, presumably because it is easier to share the same type as its petrol stablemates. Because of this, it is one of the few electric vehicles that is capable of jump-starting a petrol engine if required. The Leaf can also be jump-started itself if the 12V battery is discharged. Battery charging is via a DC-DC converter which is located in the Power Distribution Module on 2013-on models. An optional solar panel on the rear spoiler also feeds the 12V battery and is easily tested by disconnecting the battery leads and testing for voltage still present at the cables when the panel is exposed to daylight. Battery charging is switched on at all times when the vehicle is on, also when remote climate control is running and sometimes as required when the vehicle is at rest. Battery charging will not occur within the first hour after switching off. It is recommended that if you need to disconnect the battery, this is done between five minutes and one hour after switching off the vehicle. If necessary, restart the vehicle, switch off and wait five minutes. If you need to disconnect the 12V battery, cover the solar panel if fitted to ensure it does not keep the 12V system live.

The 12V battery is the most common cause of electrical problems on the Leaf, including starting problems, power steering problems, and “T/M System Malfunction” warnings.

POWER STEERING

The Leaf uses a 12V electric power steering system. Vehicle speed and start signal are CAN networked from the brake control module and vehicle control module respectively. The motor, gearbox, torque sensors and ECU are all built into a self-contained unit on the steering column.

SOUNDS

The Leaf creates an artificial whirring sound to warn pedestrians of an approaching vehicle, modelled on a Japanese commuter train, known as Vehicle Sound for Pedestrians (VSP). The VSP control module behind the glovebox receives vehicle speed and gear information via CAN from the Vehicle Control Module and drives the speaker behind the front bumper. It also makes the beep when connecting the charging cable, and controls an additional speaker under the instrument cluster for the startup sound. The buzzer for the brake warning is controlled by the brake control module.

HIGH VOLTAGE COOLING

The motor, inverter and PDM all share a liquid cooling system, with a conventional header tank, radiator and radiator fans. A variable-speed electric water pump mounted on the driver’s side of the engine bay pushes coolant down through the PDM, then inverter, then motor and up through the radiator. The pump should not be run with no coolant in the system.

The system can be bled by filling the system, then using diagnostic equipment to run the pump for one minute. If water can be heard flowing in the PDM area, run the pump until the sound goes away. Check the level is on the maximum.

The coolant temperature sensor is located in the top left corner of the radiator. There is no thermostat fitted. The water pump is operated by the Vehicle Control Module (VCM). The cooling system is pressurised to 0.3 bar- use this as a maximum if you need to pressure test the system.

EM61 Leafs with the on-board charger in the rear of the car still use a water cooled charger. Coolant pipes run the length of the car in the “transmission tunnel”.

The battery pack is not cooled (see Battery).

BRAKING SYSTEM

The Leaf’s braking system consists of a electronic master cylinder containing a motorised piston. When braking is required, the brake motor operates a screw that pushes a hydraulic cylinder, pushing fluid to the calipers in the usual way. Driver brake demand comes from a stroke sensor on the pedal. The Electronic Brake Unit and the Vehicle Control Module communicate via CAN to establish how much of the braking can be done by regeneration, and how much requires the friction brakes. Friction brakes are used exclusively when the battery is full, with regeneration also dependent on ambient temperature and vehicle speed. The Electronic Brake Unit then operates the motorised master cylinder to push fluid down to the calipers. If the power supply fails, a backup power supply unit in the rear of the vehicle provides electrical power to the braking system. There is a further backup in the event of total failure which connects the pedal to the master cylinder and operates as a conventional hydraulic system with no assistance or regeneration.

In the event of brake problems on starting the vehicle, check for any type of device fitted in the vehicle’s diagnostic connector. These devices can drain the 12V battery and interfere with CAN communication and we strongly recommend are not left connected all the time.

The Electronic Brake Unit is one unit with the ECU, master cylinder, reservoir etc, although this only creates pressure. ABS functions are handled by a conventional ABS control unit on the other side of the engine bay, and the two are linked by their own network. A yellow warning light, a red warning light and a warning buzzer are all fitted to warn the driver of a problem, depending on the severity.

Brake fluid is normally changed every two years, and bleeding is carried out with key on, engine off (press start button without touching brake pedal until ignition lights come on). Fill the brake fluid reservoir, pump the pedal a few times, then open the bleed valve and pump fluid through as required. Nissan recommends bleeding right-hand-drive Leafs in the following order: nearside rear, offside front, offside rear, nearside front.

PARKING BRAKE

EM61 models (2011-2013)
Drum-in-disc operated by an EPB motor via cables. The actuator is located under the rear of the vehicle, with the control module a separate unit in the boot area next to the brake emergency power supply. Emergency release is under a cover in the boot floor (push and rotate anti-clockwise). The parking brake will only release automatically if the vehicle is in gear, accelerator depressed and driver’s seat belt is fastened. The EPB actuator position must be relearned with diagnostic equipment if the actuator, cable or brake shoes have been disturbed. Brake shoes can be adjusted via a hole in the disc- move the adjuster wheel upwards to tighten until locked, then back off 7 clicks and make sure the wheel turns freely.

EM57 models (2013-2017)
Drum-in-disc operated by a foot pedal. Brake shoes can be adjusted via a hole in the disc. Move the adjuster wheel upwards to tighten until locked, then back off until the wheel turns freely.

DIAGNOSTICS

Many diagnostic machines will interrogate the Leaf, however many do not cover every module in the vehicle. Our preference is the G-Scan from Blue-Print. If you have a scanner that connects to the car but does not show detailed battery information, a nice little add-on is LeafSpy- not a diagnostic tool as such but a smartphone app that works through a ELM327 dongle to pick information from the vehicle’s EV CAN network. At the time of writing LeafSpy is around £15 from the App Store or Play Store and around the same again for the required ELM327 hardware.

GEARBOX

The Leaf uses a single-speed reduction gear. Because the motor is permanently and physically linked to the wheels, the Leaf cannot be towed with the driving wheels on the ground. There is both a level plug and a drain plug on the gearbox. For the ‘gear’ selector in the car, see Driving.

WHEELS & TYRES

Leaf wheels are 16” or 17”. The Leaf’s rear beam means rear camber and toe are not adjustable, and toe is the only adjustment on the front end. Although any tyres the right size will fit the Leaf, tyres with a poor efficiency rating will have a noticeable effect on driving range, and because of the car’s lack of engine noise, noisy tyres will be very noticeable. Our favourites are Michelin Energy Saver + S1, which have a A rating for efficiency, A for wet grip and noise rating of 70 dB, although these are not available for the 17” wheels. A nut at the base of the tyre valve indicates the car has TPMS.

OTHER

The Leaf’s strut tops are prone to collecting rainwater, which will rust the mounting nut and make it difficult to remove. A rubber cover is available from Nissan (part number 54330- ED000) worthwhile persuading your customer to have a pair fitted to save pain in the future!

It’s also worth mentioning bodywork repairs- the high voltage battery must be removed before the vehicle is put into an oven. If using portable paint drying equipment, use a infrared thermometer or thermal camera to monitor the sill area- it should not exceed 60°C.

Nissan service prices: Minor service : £149 Major service: £199

Warranty information: Standard vehicle warranty: 3 years/60k miles
Lithium Ion battery warranty (against failure): 5 years/60k miles Lithium Ion battery warranty (against excessive degradation*): 24kWh models: 5 years/60k miles
30kWh models: 8 years/100k miles

In addition to standard block exemption regulations, Nissan will only honour warranties if the vehicle battery pack case has not been opened.

*excessive degradation is defined as fewer than 9 of 12 battery health bars remaining.

INSTRUMENT CLUSTER:

The dots along the top show the motor power or regeneration. The gauge on the left is battery temperature, and the green light in the centre is the “ready” light that indicates the vehicle is running and will move if put into gear. The right hand gauge is the battery level, with the slim outer lights showing the capacity (lost bars indicate a degraded battery). The estimated remaining driving range is inset into the battery level gauge (90 miles in this case). The battery percentage in the centre is not shown in EM61 models.

INTERIOR BUTTONS:

Area shown to right side of steering wheel. Buttons in yellow, left to right:

  • Open Charging Port lid
  • Lock AC charging connector (auto will unlock when fully charged, lock will lock cable until unlocked).
  • Charging timer bypass: press to charge
  • Switch off Vehicle Sound for Pedestrians Green: Traction control

Blue: bonnet release. Red: diagnostic connector.

THEORETICAL LAYOUT:

 

 

 

 

 

 

 

 

 

 

  1. Switch off the vehicle and wait 5 minutes. If the vehicle has been parked for an hour or more, start the vehicle, then switch off and wait 5 minutes. Ensure the charging cable is NOT
  2. Remove the key from the vehicle and put it in a safe place at least 5 metres
  3. Disconnect the 12v
  4. Lift the cover in the transmission tunnel in front of the rear centre
  5. Remove 3 x 10mm bolts holding the metal
  6. Check your high voltage gloves for leaks by rolling them up from the open end- only use gloves that are clean, dry and free from air leaks.
  7. Wearing your high voltage gloves, remove the service
  8. Wait 10 minutes.
  9. Unlike some vehicles, the Leaf does not have a convenient place to verify that high voltage has dissipated. Therefore when working with high voltage components, you must assume the system is still live and take appropriate precautions and wear appropriate PPE until you have proved otherwise at the component.

Note: Reconnection is the reverse of disconnection. When reconnecting the 12v battery, the driver’s window will need to be reset by winding down, holding for 2 seconds, then winding up and holding for two seconds. The clock will also need to be reset (clock time set through touch screen).

Thank you to Peter Melville of HEVRA for this information.

Email: membership@hevra.org.uk

www.hevra.org.uk

www.facebook.com/HEVRAofficial

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