Great Wall GW491QE, Service Manual

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EF.1-51
Description of the diagnosis function on M7.9.7 system failure
4. Four types of failure
Failure B_mxdfpMax. indicates the signal goes beyond the upper limit of normal scope;
Failure B_mndfpMin. indicates the signal goes beyond the lower limit of normal scope;
Failure B_sidfpsignal indicates some failure without signal.
Failure caused by an inappropriate B_npdf, indicates some inappropriate signal.
5. Connection with diagnosis instrument
The system adopts ISO 9141-2 standard diagnosis plug (as shown in the figure below) to be securely connected with engine wiring
harness, and is supported by line “K” communication protocol. And Pin 4, 7, 16 on diagnosis plug shall be connected respectively
with following parts under the engine management system (EMS): Pin 4 connected to the ground wire on vehicle; Pin 7 connected to
Pin 71 of ECU, namely the engine data line K ; and Pin 16 connected to the positive electrode of accumulator.
ECU may communicate with peripheral diagnosis instruments via line K , and perform following operations:
(a)Display of engine parameters
-Rotating-speed, cooling-fluid temperature, opening degree of throttle valve, ignition lead-angle, oil-injection pulse width, inlet
airpressure, inlet-air temperature, vehicle speed, system voltage, modification to oil injection, scour rate of carbon-canister, idlespeedair
control, waveform of oxygen sensor;
-Desired rotating-speed, relative load of engine, ambient temperature, ignition closure time, temperature of evaporator, inlet air
capacity, and oil consumption.
-Signal voltage of throttle position sensor, signal voltage of cooling-fluid temperature sensor, signal voltage of inlet-air temperature
sensor, signal voltage of inlet-air pressure sensor, signal voltage for Pin 1 of knock sensor, and signal voltage for Pin 2 of knock sensor.
(b)The displayed status for electronic injection system covers:
Status of theft-prevention system, safety status, editing status, status of cooling system, status of stable working condition, status
of dynamic working condition, exhaust control status, status of oxygen sensor, idle-speed status, status of fault indicator lamp,
status under emergency, status of air-conditioner system, auto. speed changer /torque request status.
(c) Actuator test function
Fault indicator lamp, fuel pump, air-conditioner relay, fan, ignition, and oil injection single-cylinder oil cut .
(d)Display of milemeter
Mileages &time traveled.
(e)Display of version information
No. of vehicle frame VIN , No. of ECU hardware, No. of ECU software.
(f)Display of failures
Inlet-air pressure sensor, inlet-air temperature sensor, engine cooling-fluid temperature sensor, throttle position sensor, oxygen
sensor, the heating loop of oxygen sensor, modification to air /fuel ratio, oil injector inside each cylinder, fuel pump, knock sensor,
rotating speed sensor, phase sensor, carbon-canister control valve, cooling-fan relay, vehicle speed signal, rotating- speed when at
idle-speed, idle-speed adjustor, system voltage, ECU, air-conditioner compressor relay, temperature sensor of evaporator, fault
indicator lamp.
6. Read failure information via flashing code
Open the ignition switch, and have the engine data line K i e. Standard diagnosis plug No. 7 being connected to ground for at
least 2.5 seconds; The availability of fault code stored in ECU failure memory will be indicated by a flashing code (i e. P- CODE
value) output from an engine fault indicator lamp. For instance, P0203 will be flashing in the way below: ten continuous times-
intermittance- two continuous times - intermittance- ten continuous times - intermittance- three continuoustimes.
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