Nissan Leaf. Manual - part 842

SYSTEM

HCO-7

< SYSTEM DESCRIPTION >

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SYSTEM

High Voltage Cooling System

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• The HV cooling system is the system which cools the following high-voltage components.

- Traction motor

- Traction motor inverter

- PDM (Power Delivery Module)

• Coolant is circulated by means of the electric water pump, and the electric water pump is controlled by the

VCM (Vehicle Control Module).

COOLING SYSTEM DIAGRAM

JPCIA0340ZZ

PDM (Power Delivery Module)

Electric water pump

Traction motor inverter

Traction motor

To reservoir tank

To radiator

To radiator

HCO-8

< SYSTEM DESCRIPTION >

SYSTEM

HIGH VOLTAGE COOLING SYSTEM SCHEMATIC

JPCIA0375GB

RADIATOR

HCO-9

< BASIC INSPECTION >

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BASIC INSPECTION

RADIATOR

Inspection

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Check radiator for mud or clogging. If necessary, clean radiator as follows.

CAUTION:

• Be careful not to bend or damage radiator fins.

• When radiator is cleaned without removal, remove all surrounding parts such as radiator cooling fan

assembly and horns. Then tape harness and harness connectors to prevent water from entering.

1. Apply water by hose to the back side of the radiator core vertically downward.
2. Apply water again to all radiator core surfaces once per minute.
3. Stop washing if any stains no longer flow out from radiator.
4. Blow air into the back side of radiator core vertically downward.

• Use compressed air lower than 490 kPa (5 kg/cm

2

, 71 psi) and keep distance more than 30 cm (11.81

in). 

5. Blow air again into all the radiator core surfaces once per minute until no water sprays out.

HCO-10

< SYMPTOM DIAGNOSIS >

OVERHEATING CAUSE ANALYSIS

SYMPTOM DIAGNOSIS

OVERHEATING CAUSE ANALYSIS

Troubleshooting Chart

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Symptom

Check items

Cooling sys-
tem parts 
malfunction

Poor heat transfer

Water pump malfunction

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Damaged fins

Dust contamination or paper clogging

Physical damage

Clogged radiator cooling 
tube

Excess foreign material (rust, dirt, sand, etc.)

Reduced air flow

Cooling fan does not oper-
ate

Fan assembly

High resistance to fan rota-
tion

Damaged fan blades

Damaged radiator shroud

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Improper coolant mixture ratio

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Poor coolant quality

Coolant viscosity

Insufficient coolant

Coolant leakage

Cooling hose

Loose clamp

Cracked hose

Water pump

Poor sealing

Degas tank cap

Loose

Poor sealing

Radiator

O-ring for damage, deterio-
ration or improper fitting

Cracked radiator tank

Cracked radiator core

Reservoir tank

Cracked reservoir tank

Degas tank

Cracked degas tank

Except cool-
ing system 
parts mal-
function

Blocked or restricted air 
flow

Blocked bumper

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Blocked radiator grille

Installed car brassiere

Mud contamination or paper clogging

Blocked radiator

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Blocked condenser

Blocked air flow

Installed large fog lamp