Manifold absolute pressure signal is unreliable
Engine coolant temperature signal is unreliable.
Injector driver stage failure
After oxygen sensor failure mark is set, fuel
quantification closed-loop control is shut down, and
the primitive fuel injection time stored in ECU is used
to carry out fuel quantification.
Installation hints: the tightening torque of oxygen
sensor is 50-60Nm, a layer of rust preventive oil shall
be applied on oxygen sensor after replacing so as to
prevent from incapable removal in case of rust.
Troubleshooting: mainly check if the plug connection
of several wires on the sensor is in good condition, and
if there is short circuit or open circuit.
Generally, sensor damage is caused by plumbum and
phosphorus poisoning, so pay attention to fuel quality,
meanwhile excessive consumption of engine oil is
Oxygen sensor has a cable, the other end of which is
electric connection. The outside of sensor is wrapped
with asbestos fireproof covering.
There are 4 pins on the joint:
1# connecting with heating control (ECU1#);
2# connecting with heating power and main relay;
3# connecting with sensor ground (ECU36#);
4# connecting with signal (+) (ECU18#).
※ Electronic Control Unit ECU
Purpose: ECU is the core of electronic engine control
system. Sensors sent various signals to ECU for
electric control, and then ECU controls operations of
fuel injector and ignition coil, etc. after internal
calculation, thus controlling working of engine.
Normal operation voltage: 9-16V
Composition: it has shielded casing and printed
circuit board, which integrates lots of electronic
control units for the control of EFI system.
氧传感器内部构造图
Interior structure of oxygen sensor
ECU