Page 137 of 1184

ENGINE CONTROLS 1F–39
DAEWOO M-150 BL2
Main Relay Circuit Check
StepActionValue(s)YesNo
1
1. Turn the ignition OFF.
2. Disconnect the engine fuse block fuse EF26.
3. Turn the ignition ON.
4. With a test light connected to the ground, probe
the fuse terminals nearest the main relay for fuse
EF19.
Is the light on at both terminal?
–
System OKGo to Step 2
2Is the light on at only one terminal?–Go to Step 3Go to Step 4
3
Repair the open in the wiring between the main relay
connector terminal 30 and the fuse EF19 as needed.
Is the repair complete?
–
System OK
–
4
1. Turn the ignition OFF.
2. Remove the main relay.
3. Turn the ignition ON.
4. With a test light connected to the ground, probe
the main relay terminals 85 and 30.
Is the light on at both terminals.
–
Go to Step 8Go to Step 5
5
1. Turn the ignition OFF.
2. Check engine fuse block fuse EF19.
Is one or both fuse blown?
–
Go to Step 6Go to Step 7
6
1. Repair short circuit between terminal 87 of main
relay and heated oxygen sensor
2. Replace fuse EF19.
Is the repair complete?
–
System OK
–
7
Repair open circuit between terminal 30 of main
relay and fuse EF19.
Is the repair complete?
–
System OKGo to Step 8
8
1. Turn the ignition OFF.
2. Measure the resistance between following
terminals.
Terminal 86 of main relay and ground.
Terminal 87 of main relay and ground.
Is the resistance within the specified value
0 ΩGo to Step 10Go to Step 9
9Repair open circuit.
Is the repair complete?–System OK–
10Replace the main relay.
Is the repair complete?–System OK–
Page 138 of 1184
1F–40 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F060
MANIFOLD ABSOLUTE PRESSURE CHECK
Circuit Description
The Manifold Absolute Pressure (MAP) sensor measure
the changes in the intake manifold pressure which result
from engine load (intake manifold vacuum) and rpm
changes. The MAP sensor converts these changes into
voltage output. The Engine Control Module (ECM) send
a 5-volt reference voltage to the MAP sensor. As the in-
take manifold pressure changes, the output voltage ofMAP sensor also changes. A low voltage (high vacuum)
output of 1 to 1.5 volts is present at idle. A high voltage
(low vacuum) output of 4.5 to 5.0 volts is present at wide
open throttle. The MAP sensor is also used under cer-
tain conditions to measure barometric attitude changes.
The ECM uses the MAP sensor for the delivery and igni-
tion timing changes.
Page 139 of 1184

ENGINE CONTROLS 1F–41
DAEWOO M-150 BL2
Manifold Absolute Pressure Check
StepActionValue(s)YesNo
1
1. Turn the ignition OFF.
2. Connect a scan tool to the Data Link Connector
(DLC).
3. Turn the ignition ON.
4. Compare the Manifold Absolute Pressure (MAP)
sensor voltage reading from scanner with that
from known good vehicle.
Is the difference in the two voltage reading less than
the value specified?
0.4 VGo to Step 2Go to Step 5
2
1. Turn the ignition OFF.
2. Connect a scan tool to the DLC.
3. Disconnect the MAP sensor vacuum line.
4. Connect a hand vacuum pump to the Map sensor.
5. Turn the ignition ON.
6. Note the MAP sensor voltage.
7. Apply 34kPa (10 in. Hg) of vacuum to the Map
sensor and note the voltage change.
Is the difference in voltage readings more than the
value specified?
1.5 VSystem OKGo to Step 3
3Inspect the MAP sensor connector terminals.
Is the problem found.–Go to Step 4Go to Step 5
4
Repair the MAP sensor connector terminals as
needed.
Is the repair complete?
–
System OK
–
5Replace the MAP sensor.
Is the repair complete?–System OK–
Page 140 of 1184

1F–42 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F070
IDLE AIR CONTROL SYSTEM CHECK
Circuit Description
The Engine Control Module (ECM) controls the engine
idle speed with the Idle Air Control (IAC) valve. To in-
crease the idle speed, the ECM pulls the IAC pintle
away from its seat, allowing more air to pass by the
throttle body. To decrease the idle speed, it extends the
IAC valve pintle toward its seat, reducing bypass air
flow. A scan tool will read the ECM commands to the
IAC valve in counts. The higher counts indicate more air
bypass (higher idle). The lower counts indicate less air is
allowed to bypass (lower idle).
Diagnostic Aids
If the idle is too high, stop the engine. Fully extend the
Idle Air Control (IAC) valve with a IAC driver. Start the
engine. If the idle speed is above 950 rpm, locate and
repair the vacuum leak. Also, check for a binding throttle
plate or throttle linkage or an incorrect base idle setting.
Idle Air Control Valve Reset Procedure
Whenever the battery cable or the Engine Control Mod-
ule (ECM) connector or the ECM fuse EF6 is discon-nected or replaced, the following idle learn procedure
must be performed:
1. Turn the ignition ON for 5 seconds.
2. Turn the ignition OFF for 10 seconds.
3. Turn the ignition ON for 5 seconds.
4. Start the engine in park/neutral.
5. Allow the engine to run until the engine coolant is
above 85C (185F ).
6. Turn the A/C ON for 10 seconds, if equipped.
7. Turn the A/C OFF for 10 seconds, if equipped.
8. If the vehicle is equipped with an automatic trans-
axle, apply the parking brake. While pressing the
brake pedal, place the transaxle in D (drive).
9. Turn the A/C ON for 10 seconds, if equipped.
10. Turn the A/C OFF for 10 seconds, if equipped.
11. Turn the ignition OFF. The idle learn procedure is
complete.
Page 141 of 1184

ENGINE CONTROLS 1F–43
DAEWOO M-150 BL2
Idle Air Control System Check
StepActionValue(s)YesNo
1
Perform an Euro On-Board Diagnostic (EOBD)
system check.
Was the check performed?
–
Go to Step 2
Go to “Euro
On-Board
Diagnostic
System Check”
2
1. Turn the ignition OFF.
2. Remove Idle Air Control (IAC) valve.
3. Inspect the IAC passages for restrictions.
Is the problem found?
–
Go to Step 3Go to Step 4
3Clean the IAC passages.
Is the repair complete?–System OK–
4
Measure the resistance between following terminals
of IAC valve.
Terminal A and B
Terminal C and D
Does the resistance equal to the value specified?
40–80 ΩGo to Step 6Go to Step 5
5Replace the IAC valve.
Is the repair complete?–System OK–
6
1. Disconnect the Engine control Module (ECM)
connector.
2. Check for an open or short in the wires between
following terminals.
Terminal A of IAC valve connector and terminal
70 of ECM connector
Terminal B of IAC valve connector and terminal
71 of ECM connector
Terminal C of IAC valve connector and terminal
42 of ECM connector
Terminal D of IAC valve connector and terminal
72 of ECM connector
Is the problem found?
–
Go to Step 8Go to Step 7
7Repair an open or short circuit as needed.
Is the repair complete?–System OK–
8
Inspect the IAC connector terminals and the ECM
connector terminals.
Is the problem found?
–
Go to Step 9Go to Step 10
9
Repair or replace the throttle body assembly and/or
ECM connector terminals as needed.
Is the repair complete?
–
System OK
–
10Replace the ECM.
Is the repair complete?–System OK–
Page 142 of 1184
1F–44 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F080
IGNITION SYSTEM CHECK
Page 143 of 1184

ENGINE CONTROLS 1F–45
DAEWOO M-150 BL2
IGNITION SYSTEM CHECK
Circuit Description
The Electronic Ignition (EI) system uses a waste spark
method of spark distribution. In this type of EI system,
the Crankshaft Position (CKP) sensor is mounted to the
oil pump near a slotted wheel that is a part of the crank-
shaft pulley. The CKP sensor sends reference pulses to
the Engine Control Module (ECM). The ECM then trig-gers the EI system ignition coil. Each cylinder is individu-
al with coil per cylinder in sequence.
This leaves the remainder of the high voltage to be used
to fire the spark plug in the cylinder on its compression
stroke. Since the CKP sensor is in a fixed position, tim-
ing adjustments are not possible or needed.
Ignition System Check
Caution: Use only electrically insulated pliers when
handling ignition wires with the engine running to
prevent an electrical shock.
StepActionValue(s)YesNo
1
1. Remove the spark plugs.
2. Inspect for wet spark plugs, cracks, wear,
improper gap, burned electrodes, or heavy
deposits.
3. Replace the spark plugs as needed.
Is the repair complete?
–
System OKGo to Step 2
2
Check for the presence of spark from all of the
ignition wires while cranking the engine.
Is spark present from all of the ignition wires?
–
System OKGo to Step 3
3
1. Measure the resistance of the ignition wires.
2. Replace any ignition wire(s) with a resistance
above the value specified.
3. Check for the presence of spark from all of the
ignition wires.
Is spark present from all of the ignition wires?
30000 ΩSystem OKGo to Step 4
4Is spark present from at least one of the ignition
wires, but not all of the ignition wires?Go to Step 5Go to Step 12
5
1. Turn the ignition OFF.
2. Disconnect the Electronic Ignition (EI) system
ignition coil connector.
3. While cranking the engine, measure the voltage
at the EI system ignition coil connector terminal 1.
Does the voltage fluctuate within the values
specified?
0.2–2.0 VGo to Step 8Go to Step 6
6
Check for an open in the wire from EI system
ignition coil connector terminal 1 to the Engine
Control Module (ECM) connector terminal 66.
Is the problem found?
–
Go to Step 7Go to Step 11
7
1. Repair the wiring as needed.
2. Connect the EI system ignition coil connector.
3. Check for the presence of spark from all of the
ignition wires.
Is spark present from all of the ignition wires?
–
System OK
–
8
While cranking the engine, measure the voltage at
the EI system ignition coil connector terminal 2.
Does the voltage fluctuate within the values
specified?
0.2–2.0 VGo to Step 10Go to Step 9
Page 144 of 1184

1F–46 ENGINE CONTROLS
DAEWOO M-150 BL2
Ignition System Check (Cont’d)
StepActionValue(s)YesNo
9
Check for an open in the wire from EI system
ignition coil connector terminal 2 to the Engine
Control Module (ECM) connector terminal 1.
Is the problem found?
–
Go to Step 7Go to Step 11
10
1. Replace the EI system ignition coil.
2. Connect the EI system ignition coil connector.
3. Check for the presence of spark from all of the
ignition wires.
Is spark present from all of the ignition wires?
–
System OK
–
11
1. Replace the ECM.
2. Connect the EI system ignition coil connector.
3. Check for the presence of spark from all of the
ignition wires.
Is spark present from all of the ignition wires?
–
System OK
–
12
1. Turn the ignition OFF.
2. Disconnect the crankshaft position (CKP) sensor
connector.
3. Measure the resistance between the CKP sensor
terminals 1 and 2.
Is the resistance within the value specified?
4. Measure the resistance between following
terminals.
Terminals 1 and 3 of CKP sensor.
Terminals 2 and 3 of CKP sensor.
Is the resistance within the value specified?
400–600 Ω
∞
Go to Step 14Go to Step 13
13Replace the crankshaft position sensor.
Is the repair complete?–System OK–
14
1. Turn the ignition ON.
2. Measure the voltage between the CKP sensor
connector terminals 1 and 3.
Is the voltage within the value specified?
0.95–1.10 VGo to Step 20Go to Step 15
15
Measure the voltage between the CKP sensor
connector terminal 1 and ground.
Is the voltage within the value specified?
0.95–1.10 VGo to Step 18Go to Step 16
16
Check the wire between the CKP sensor connector
terminal 1 and the ECM connector terminal 54 for an
open or short.
Is the problem found?
–
Go to Step 17Go to Step 10
17
Repair the wire between the CKP sensor connector
terminal 1 and the ECM connector terminal 54.
Is the repair complete?
–
System OK
–
18
Check the wire between the CKP sensor connector
terminal 3 and ground for an open or short.
Is the problem found?
–
Go to Step 19Go to Step 11
19
Repair the wire between the CKP sensor connector
terminal 3 and ground.
Is the repair complete?
–
System OK
–
20
1. Turn the ignition ON.
2. Measure the voltage between the CKP sensor
connector terminals 2 and 3.
Is the voltage within the value specified?
0.95–1.10 VGo to Step 24Go to Step 21