General Precautions of EFI System Maintenance
F-95
determine it to be the malfunction of lean mixed gas, when self-learning in medium load area reaches the
upper limit value set by the system (lean mixed gas, and the system continuously increasing the fuel injection
volume up to the maximum value).
Malfunction Diagnostic Guide:
Required Equipment: (Diagnostic Instrument with EOBD Diagnostic Function)
Step I: Use diagnostic instrument to read the malfunction information
Read Result I Read Result II
MIL Lamp On P-CODE Present MIL Lamp Off P-CODE Present
P2187 P2187
Maintenance tips:
The malfunction has been confirmed, and the following
problems may possibly exist
1) Fuel injector blocked and cleaning required
2) Air leakage with intake and exhaust system
3) Excessive sedimentation of colloidal matter in the air
intake pipeline or on the back of intake valve, and
cleaning required
4) Deviation in parts of engine
Maintenance tips:
The malfunction has not bee finally confirmed,
and wait for system to fulfill diagnosis.
126. P2188 Air-Fuel Ratio for Self-learning Value under Closed-Loop Control
Exceeding Lower Limit (Low Load Area)
Description about Principle and Malfunction Cause:
In order to optimize the integrated transformation efficiency of catalytic converter to HC, CO, and NOx, the
air-fuel ratio of the mixed gas shall be controlled at 14.7:1. If it is found the deviation in manufacture of parts,
the sedimentation of colloidal matters in gasoline on the fuel injector, the air intake pipeline, or the back of
valve, and air leakage exists with intake and exhaust system, all these factors will give rise to a deviation from
14.7:1 in the air-fuel ratio to different degrees (rich or lean), which will lead to deteriorated emission and
reduction in engine performance.
The engine control system is able to make amendments and self-learning on fuel injection volume according
to the degree and characteristic of deviation in air-fuel ratio. The self-learning of deviation in air-fuel ratio is
divided into “Self-learning in Small Load Area” and “Self-learning in Medium Load Area”. The system will
determine it to be the malfunction of rich mixed gas, when self-learning in medium load area reaches the
lower limit value set by the system (rich mixed gas, and the system continuously decreasing the fuel injection
volume up to the minimum value).
Malfunction Diagnostic Guide:
Required Equipment: (Diagnostic Instrument with EOBD Diagnostic Function)
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