89 

 
No. 051 Cooling water unusually consumed   

Malfunction Causes 

Solution 

Cooling system leaking   

Check water tank, water bottle, pipe, radiator, radiator cap, warm-wind 
radiator are water leaking; repair or replace. (pay attention to unusual 
consumption of cooling water caused by deformed assembling of rubber ring 
of radiator cap) 

Cylinder ring malfunction 

Cylinder ring is damaged or not pressed out. After startup of engine, water 
enters to crankcase or combustion chamber through cylinder ring; 
combustion chamber is through with water duct; if there is bubble out or water 
column spraying out of cooling water, it will cause unusual cooling water; 
observe engine oil is emulsified; if so, replace cylinder ring;   

Water without anti-freezing 
efficiency, causing icing after 
parking in winter   

This malfunction is rare in higher temperature area, but still with possibility; in 
case of this situation, replace anti-freezing liquid conforming to requirements; 

Cylinder cover with cracks 

Cylinder cover with cracks, which will be increased under heating, and water 
will enter to crankcase or combustion chamber through cracks. Under this 
situation, check carefully cylinder cover is with cracks; if necessary, use 
special instruments; in case of cracks, replace it;   

Cooling water of 
the engine 
consumed too 
much during 
using 

Cylinder body with cracks   

Cylinder body with cracks, which will be increased under heating, and water 
will enter to crankcase or combustion chamber through cracks. Under this 
situation, check carefully cylinder body is with cracks; if necessary, use 
special instruments; in case of cracks, replace it; 

 

Repair or 
replace 

Cooling system leaking 

Cylinder ring 
malfunction 

Water without antifreezing efficiency, causing icing after 
parking in winter 

Cylinder cover with cracks 

Cylinder body with cracks 

Consumption of 
cooling water 

Replace 

Replace 

Replace 

Replace 

Normal 

Cracks 

Normal 

Normal 

Normal 

Icing 

Abnormal 

Leaking 

Cracks 

 
 

 

 

90 

 
No. 052 Low engine oil pressure   

Malfunction Causes 

Solution 

Insufficient lubricating oil   

Check engine oil; if necessary, replace or add lubricating oil;   

Oil viscosity too small 

Use engine oil with correct grade; at least above SG of summer 
SAE10W-40/winter 5W-30 

Check oil screen is blocked; if so, clean or replace;   

Oil pump malfunction   

Check clearance between drive gear and driven gear of oil pump. And 
check relief valve is blocked; if so, repair or replace; 

Clearance of connecting rod tile 
too large, causing oil leaking 

Check clearance of connecting rod tile is too large, causing oil leaking; 
if so, repair or replace;   

Clearance of crankshaft tile too 
large, causing oil leaking 

Check clearance of crankshaft tile is too large, causing oil leaking; if so, 
repair or replace; 

Main oil duct blocked or leaking  Analyze causes and repair accordingly;   

Oil pressure sensor or indicator 
lamp damaged 

Check electrical signal of sensor and oil indicator lamp; if abnormal, 
replace it;   

Oil induction plug leaking   

Replace induction plug 

Engine oil with too 
low pressure when 
engine is working    

High water temperature   

Eliminate malfunction one by one according to relevant template, 
making water temperature normal; 

 

Add 

Repair or 
replace 

Low engine oil pressure 

Insufficient lubricating oil 

Oil viscosity too small 

Oil pressure sensor or indicator lamp 
damaged 

Clearance of connecting rod tile too large, 
causing oil leaking 

Clearance of crankshaft tile too large, causing oil leaking 

Main oil duct blocked or leaking 

Replace 

Repair 

Repair 

Replace 

Normal 

Insufficient 

Normal 

Normal 

Normal 

Normal 

Too small 

Damaged 

Too large 

Too large 

Blocked or leaking 

 
 

 

 

91 

Quick diagnosis for M1.5.4 Electrical injection system components of 

MR479 engine

 

 

No.053 Quick diagnosis for ECU   

 
Power source: 

Power supplied by the battery continuously via 18# pin; Power supplied while main relay is 
turned on via 37# pin; power supplied while ignition switch is turned on via 27# pin. Earthing:   

2#, 10#, 14#, 19#, 24#, 30#, 48# pin. Malfunction diagnosis interface: 

55# pin, engine data K line. Call out malfunction information records within ECU via K line, or 
manually input some instructions, such as clear malfunction information records, make idle 
speed actuator self-learning, etc;   

General causes:   

1. Invalid caused by burnt and damaged parts and components within ECU due to electrical 
overload of externally connected device;   

2. ECU entered with water causing circuit board rusty, etc; Maintenance precautions:   

1. Before removing ECU, remove battery cell firstly;   

2. For welding on the vehicles, cut off ECU power source;   

3. Close ignition switch firstly while startup with externally connected power source or as 
externally connected power source;   

4. Radio speaker could not approach the controller; Simple measuring method:   

1 (connect the connector) Read engine malfunction records via engine data K line, and make 
comparison based on engine system data and normal vehicle data, find out differences and 
continue in-depth inquiry;   

2 (Remove the connector) check ECU connections are complete, and mainly check ECU power 
supply, earthing lines are normal;   

3. Check external sensor is working normally, output signal is reliable, and its lines are complete;   

4. Recommend the ECU replaced to be assembled in the normal vehicle, and simulate 
malfunction malfunction, and further confirm the malfunction;   

 
 

 

 

92 

 

Diagnosis flowchart for voltage of M1.5.4 electrical injection system