ENGINE CONTROLS 1F–107
DAEWOO M-150 BL2
DTC P0171 – Fuel Trim System Too Lean
Step Action Value(s) Yes No
1
Perform an Euro On-Board Diagnostic (EOBD)
System Check.
Is the system check complete?
–
Go to Step 2
Go to
“On-Board
Diagnostic
System Check”
2
1. Install the scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
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 Long Term Fuel Trim value below the
specified value? –22% 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 Long Term Fuel Trim value go below the
specified value while operating under the specified
conditions? –22% Go to Step 16 Go to Step 5
5
Visually/physically check the following items:
D Vacuum hoses for splits, kinks and improper
connections.
D Crankcase ventilation oil/air separator for proper
installation.
D Exhaust system for corrosion, leaks, loose or
missing hardware.
D Oxygen sensor (O2S) is installed securely and
the pigtail harness is not contacting exhaust
manifold or engine.
D Fuel for excessive water, alcohol, or other
contaminants.
D Engine Control Module (ECM) and sensor
grounds are clean, tight, and in their proper
locations.
Do any of the above checks isolate a condition
requiring repair?
–
Go to Step 7 Go to Step 6
6
1. Disconnect the Manifold Absolute Pressure
(MAP) sensor electrical connector.
2. Operate the vehicle in Closed Loop while
monitoring the Long Term Fuel Trim value.
Is the Long Term Fuel Trim value below the
specified value? –22% Go to Step 15 Go to Step 9
7
1. Repair the malfunction found in Step 5.
2. Recheck the Long Term Fuel Trim value while
operating the engine.
Is the Long Term Fuel Trim value below the
specified value?
–22% Go to Step 8 Go to Step 9
8
Lean condition is not present.
Does a driveability problem exist?
–
Go to
“Symptom
Diagnosis” Go to Step 16
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