Daewoo CIELO EURO III, Manual

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ENGINE CONTROLS 1F – 190
DAEWOO T-154 BL2,3
injector. The water causes a lean exhaust and can set
DTC P0171.
Check for poor O2S 1 or MAP sensor connection at the
ECM. Inspect the harness connectors for the fol-
lowing conditions:
Backed-out terminals
Improper mating
Broken locks
Improperly formed
Damaged terminals
Poor terminal to wire connection
Inspect the wiring harness for damage. If the harness
appears to be OK, observe the O2S 1 display on the
scan tool while moving the connectors and the wiring
harness related to the engine harness. A change in the
display will indicate the location of the fault.
Check the brake power booster check valve for possible
leaks.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Table.
1. The On-Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and to store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
5. Visually/physically checking items which may cause
a lean condition may determine the cause of the
DTC being set and save diagnosis time.
9. A vacuum leak can change the Fuel Trim Index and
set DTC P0171. This step checks the intake man-
ifold for vacuum leaks.
11. Contaminants in fuel, such as alcohol or water, can
create a lean condition setting DTC P0171. Check-
ing for these contaminants could identify the mal-
function.
17. If no faults have been found at this point and no
additional DTCs were set, refer to “Diagnostic Aids”
for additional checks and information.
DTC P0171 Fuel Trim System Too Lean
Step Action Value Yes No
1
Perform an On-Board Diagnostic (EOBD) System
Check.
Is the system check complete?
–
Go to Step 2
Go to
“On-Board
Diagnostic
System Check”
2
Install the scan tool.
Are any component related Diagnostic Trouble
Codes (DTCs) set?
– Go to applicable
DTC table Go to Step 3
3
With the engine running, operate the vehicle until the
LOOP STATUS indicates closed.
Is the Fuel Trim Index below the specified value?
25% Go to Step 4 Go to Step 5
4
1. Turn the ignition switch ON, with the engine OFF.
2. Review the Freeze Frame data and note the
parameters.
3. Operate the vehicle within the Freeze Frame
conditions and Conditions for Setting The DTC as
noted.
Does the Fuel Trim Index go below the specified
value while operating under the specified condi-
tions?
25% Go to Step 16 Go to Step 5