1F–108 ENGINE CONTROLS
DAEWOO M-150 BL2
DTC P0171 – Fuel Trim System Too Lean (Cont’d)
StepActionValue(s)YesNo
9
1. Visually/physically inspect the following items for
vacuum leaks:
Intake manifold.
Throttle body.
Injector O-rings.
2. Repair any leaks found as necessary.
Is the repair complete?
–
Go to Step 16Go to Step 16
10
Allow the engine to idle.
Are the Idle Air Control (IAC) counts above the
specified value?
5Go to Step 11Go to Step 12
11
Check the fuel for excessive water, alcohol, or other
contaminants and correct the contaminated fuel
condition if present.
Is the repair complete?
–
Go to Step 16Go to Step 13
12
Check the IAC valve performance. Refer to “DTC
P0506 Idle Speed RPM Lower Than Desired Idle
Speed” or “DTC P0507 Idle Speed RPM Higher
Than Desired Idle Speed” in this section and repair
as necessary.
Is the repair complete?
–
Go to Step 16Go to Step 13
13
1. Connect a fuel pressure gauge to the fuel system.
2. Turn the ignition OFF for at least 10 seconds.
3. Turn the ignition ON, with the engine OFF. The
fuel pump will run for approximately 2–3 seconds.
It may be necessary to cycle the ignition switch
ON more than once to obtain maximum fuel
pressure.
4. Note the fuel pressure with the fuel pump running.
The pressure should be within the specified value.
When the fuel pump stops, the pressure may vary
slightly then hold steady.
Is the fuel pressure steady and does the fuel
pressure hold?
380 KPa
(55 psi)
Go to Step 14
Go to
“Fuel System
Diagnosis”
14
1. Start and idle the engine at normal operating
temperature.
2. The fuel pressure noted in the above step should
drop by the indicated value.
Does the fuel pressure drop by the indicated value?
21–69 KPa
(3–10 psi)
Go to
“Fuel Injector
2alance Test”Go to
“Fuel System
Diagnosis”
15Replace the MAP sensor.
Is the action complete?–Go to Step 16–
16
1. Using the scan tool, clear the Diagnostic Trouble
Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the Conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?
–
Go to Step 17Go to Step 2
17
Check if any additional DTCs are set.
Are any DTCs displayed that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK
ENGINE CONTROLS 1F–283
DAEWOO M-150 BL2
HARD START
Definition: The engine cranks OK, but does not start for
a long time. The engine eventually runs or may start and
immediately die.Important: Ensure that the driver is using the correct
starting procedure. Before diagnosing, check service
bulletins for updates.
StepActionValue(s)YesNo
1
Were the Important Preliminary Checks performed?
–
Go to Step 2
Go to
“Important
Preliminary
Checks”
2
1. Connect the scan tool to the Data Link Connector
(DLC).
2. Check the Engine Coolant Temperature (ECT)
sensor and the Intake Air Temperature (IAT)
sensor using the scan tool.
3. Compare the coolant temperature and the IAT
with the ambient temperature when the engine is
cold.
Do the ECT and the IAT readings differ from the
ambient temperature by more than the value
specified?
3C (5F)Go to Step 3Go to Step 4
3
1. Measure the resistance of the ECT sensor and
the IAT sensor.
2. Compare the resistance value to specifications
using the Temperature Vs. Resistance tables for
DTCs P0118 and P0113.
3. If the resistance is not the same, replace the
faulty sensor.
Is the repair complete?
–
System OK
–
4
1. Check for a sticking throttle shaft or a binding
linkage that may cause a high Throttle Position
(TP) sensor voltage. Repair or replace as
needed.
2. Check the TP sensor voltage reading with the
throttle closed.
Does the voltage measure within the value
specified?
0.4–0.8 VGo to Step 5Go to Step 26
5
1. Check the Manifold Absolute Pressure (MAP)
sensor response and accuracy.
2. Replace the MAP sensor as needed.
Is the repair complete?
–
System OKGo to Step 6
6
Check the fuel pump operation.
Does the fuel pump operate for the specified time
when the ignition switch is turned ON?
2 secGo to Step 7
Go to “Fuel
Pump Relay
Circuit Check”
7Check the fuel system pressure.
Is the fuel pressure within the specifications?380 kPa
(55 psi)
Go to Step 8Go to Step 27
8Check for water contamination in the fuel.
Is fuel contaminated?–Go to Step 9Go to Step 10
9Replace the contaminated fuel.
Is the repair complete?–System OK–