Great Wall GW491QE, Service Manual

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EF.2-30
Attached฀figure฀III฀and฀IV฀are฀Electric-Control฀Schematic฀diagram฀for฀MT20U฀SystemAttached฀figure฀V,฀VI,฀VII,฀and฀VIII฀are฀Typical
Failure฀Diagnosis฀Flow฀Diagram.
( b)฀Slack฀accelerating
- Check฀oil฀amount฀and฀the฀fuel฀filter฀inside฀oil฀tank
-฀฀฀Check฀the฀air฀exhaust฀system฀for฀blockage eg. whether฀three-way฀catalytic฀converter฀has฀been฀blocked฀due฀to฀฀breakage฀or฀the
burning฀of฀machine-oil;฀when฀at฀a฀normal฀idle฀speed,฀the฀pressure฀value฀of฀inlet฀manifold฀shall฀be฀greater฀฀than฀60KPa
฀-฀฀Verify฀whether฀the฀pressure฀within฀fuel฀supply฀loop฀is฀300kPa,฀and฀clean฀the฀oil฀nuzzle .
(c)฀Oil฀consumption฀is฀abnormally฀high
-฀฀After฀a฀verification฀that฀the฀mechanical฀components฀of฀engine฀and฀the฀oxygen฀sensor฀are฀under฀a฀normal฀condition,฀start฀the฀engine
and฀observe฀the฀read฀value฀of฀oxygen฀sensor:฀the฀read฀value฀shall฀be฀always฀greater฀than฀500mV฀when฀at฀a฀normal฀water฀temperature.
And฀check฀whether฀the฀injector฀is฀leaking฀oil,฀and฀whether฀the฀water฀temperature฀sensor,฀and฀the฀฀฀manifold฀pressure฀sensor฀are
working฀in฀a฀normal฀way.
(d)฀Indicating฀a฀failure฀with฀the฀air฀conditioner฀system฀is฀produced฀on฀vehicles฀without฀air฀conditioner.
-฀฀Check฀whether฀the฀pre-installed฀air฀conditioner฀plug฀has฀been฀contaminated,฀if฀so,฀clean฀it฀and฀provide฀it฀with฀a฀dustproof
protection,฀then฀ECU฀power฀supply฀will฀be฀disconnected,฀and฀resumed฀in฀ten฀minutes.
-฀฀Fault฀code฀must฀be฀cleared฀away฀from฀MT20฀system฀using฀a฀Fault฀Diagnosis฀Instrument
(e)฀Removal฀of฀common฀failures฀on฀theft-prevention฀controller
-฀฀The฀theft-prevention฀indicator฀light฀is฀not฀on Check฀the฀power฀supply฀and฀the฀ground฀wire฀for฀theft-prevention฀controller;฀As
฀the฀failure฀of฀control฀computer฀results฀from฀a฀current฀impact฀which฀is฀produced฀at฀the฀time฀when฀inductive฀load฀on฀฀accumulator฀jar
฀line฀is฀cut฀off,฀the฀electrical-injection฀system฀and฀the฀theft฀detector฀fuse฀shall฀be฀pulled฀out,฀and฀re-inserted฀after฀ten฀seconds.
-฀฀฀Subject฀to฀a฀mating฀between฀electrical-injection฀control฀and฀theft฀detector,฀the฀engine฀fault฀indicator฀light,฀after฀an฀ignition,฀will฀be
flashing฀(at฀2Hz)฀for฀30฀seconds,฀and฀then฀be฀off;฀The฀electrical-injection฀unable฀to฀start฀(the฀electrical-injection฀indicator฀light฀will
be฀flashing฀at฀1H) the฀theft-prevention฀indicator฀light฀will฀be฀on฀for฀2฀seconds฀after฀a฀normal฀ignition,฀and฀then฀be฀off;฀Try฀to
replace฀the฀password฀key;฀when฀PCHUB฀is฀used฀to฀measure฀the฀electrical-injection฀controller,฀the฀unselected฀<no฀key>may฀be
seen,฀which฀indicates฀that฀the฀password฀key฀does฀not฀have฀a฀valid฀password฀repeater That฀the฀selected฀<฀theft฀detector฀no
response>฀is฀seen฀indicates฀that฀the฀communication฀between฀the฀electrical-injection฀controller฀and฀the฀theft฀detector฀has฀not฀been
฀connected.
-฀฀฀When฀the฀electrical-injection฀control฀has฀mated฀with฀the฀theft฀detector,฀it฀will฀be฀flashing฀at฀2Hz฀for฀30฀seconds฀after฀an฀ignition,
then฀be฀off,฀and฀the฀electrical-injection฀is฀starting฀(the฀electrical-injection฀indicator฀light฀is฀permanently฀on฀or฀off),฀the฀theft฀prevention
indicator฀light฀will฀be฀on฀for฀2฀seconds฀after฀a฀normal฀ignition,฀and฀then฀be฀off;฀Such฀failure฀is฀caused฀by฀coils฀having฀not฀be฀fastened
onto฀the฀ignition฀lock฀nut,฀or฀ignition฀nuts฀having฀troubles฀with฀the฀raw฀material;฀Watch฀and฀see฀if฀it฀returns฀to฀a฀normal฀condition฀after
coils฀have฀been฀re-fastened฀onto฀the฀ignition฀lock฀nut฀(unscrewing฀the฀nuts฀may฀be฀needed฀before฀coils฀arere-fastened)฀;฀A฀large฀hole
in฀supporting฀bracket฀for฀ignition฀lock฀might฀make฀coils฀unable฀to฀be฀installed฀onto฀the฀ignition฀lock฀nut;฀if฀it฀is฀still฀unable฀back฀to฀a
normal฀condition,฀the฀ignition฀lock฀nut฀or฀coils฀may฀be฀changed.
(f)฀฀The฀key฀to฀the฀theft-prevention฀controller฀is฀lost฀or฀damaged:
Normally,฀the฀theft฀detector฀within฀electrical-injection฀system฀has฀been฀provided฀with฀two฀types฀of฀key:฀one฀in฀red,฀others฀in฀black.
And฀only฀black฀keys฀are฀for฀routine฀use.
-฀฀฀Black฀key฀lost Provide฀with฀one฀new฀black฀key,฀and฀a฀code฀operation฀study฀for฀black฀key฀is฀needed.
-฀฀฀Red฀key฀lost Provide฀with฀new฀red฀&black฀keys
Change฀the฀original฀theft-detection฀computer,฀as฀the฀theft-detector฀computer฀provided฀for฀original฀vehicle฀only฀accepts฀original
฀red฀key,฀which฀is฀a฀mark฀to฀start฀the฀key฀study฀flow฀process.฀And฀computer฀ECU฀for฀engine฀needs฀to฀be฀posted฀to฀Delphi฀company
for฀a฀decoding฀process,฀as฀computer฀ECU฀for฀engine฀only฀accepts฀an฀original฀mark฀provided฀for฀original฀vehicle฀to฀start฀฀the฀theft-
detector฀computer฀flow฀process.
A฀study฀on฀red฀key฀and฀black฀key฀is฀needed,฀and฀shall฀be฀performed฀successively฀in฀accordance฀with฀the฀code฀operation฀study฀steps
corresponding฀to฀theft-detector฀key.
(The฀code฀operation฀study฀steps฀corresponding฀to฀theft-detector฀key฀may฀be฀claimed฀from฀Delphi฀Company).
Figure฀1฀and฀2฀are฀the฀Electronic฀Principle฀Diagram฀for฀ITMS-6฀system.
Figure฀3฀and฀4฀are฀the฀Electronic฀Principle฀Diagram฀for฀MT20U฀system.
Figure฀5,6,7฀and฀8฀are฀the฀Diagnosis฀Process฀of฀Typical฀Failures.
Delphi฀engine฀management฀system-troubleshooting฀and฀common฀failure
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