Daewoo MATIZ Service Manual page 384

1F – 286 ENGINE CONTROLS
Definition: Engine power variation under steady throttle
or cruise. Feels like the vehicle speeds up and slows
down with no change in the accelerator pedal position.
Step
Were the Important Preliminary Checks performed?
1
Connect the scan tool to the Data Link Connector
(DLC).
2
Does the oxygen sensor (O2S) respond quickly to
different throttle positions?
1. Check the O2S for silicone or other contaminants
from fuel or use of improper Room Temperature
Vulcanizing (RTV) sealant.
3
2. Replace the contaminated O2S.
Is the repair complete?
1. Drive the vehicle at the speed of the complaint.
2. Monitor the long term fuel trim reading using the
4 scan tool.
Is the long term fuel trim reading within the value
specified?
Is the long term fuel trim reading below the value
5 specified?
Is the long term fuel trim reading above the value
specified?
6
Check the fuel system pressure while the condition
exists.
7
Is the fuel system pressure within specifications?
Check the in-line fuel filter.
8
Is the filter dirty or plugged?
Perform an injector diagnosis.
9
Did the injector diagnosis pinpoint the problem?
1. Check for proper ignition voltage output using a
spark tester.
2. Inspect the spark plugs for cracks, wear, improper
10
gap, burned electrodes, or heavy deposits.
Is the problem found?
Repair or replace any ignition system components
as needed.
11
Is the repair complete?
1. Inspect the ECM grounds for being clean, tight,
and in their proper locations.
12
2. Inspect the vacuum lines for kinks or leaks.
Is the problem found?
SURGES OR CHUGGLES
Action
Important: Make sure the driver understands A/C com-
pressor operation as described in the owner's manual.
The speedometer reading and the speed reading on the
scan tool should be equal.
Before diagnosing the symptom, check service bulletins
for updates.
Value(s)
–
Go to Step 2
–
Go to Step 4
–
System OK
–20–25% Go to Step 7
"Diagnostic Aids
–20% for DTC P0172"
"Diagnostic Aids
25% for DTC P0171"
380 kPa
(55 psi) Go to Step 8
–
Go to Step 18
–
Go to Step 19
–
Go to Step 11
–
System OK
–
Go to Step 13
Yes No
Go to
"Important
Preliminary
Checks"
Go to Step 3
–
Go to Step 5
Go to
Go to Step 6
Go to
–
Go to Step 17
Go to Step 9
Go to Step 10
Go to Step 12
–
Go to Step 14
DAEWOO M-150 BL2