ENGINE CONTROLS 1F–15
DAEWOO M-150 BL2
made to enter DTC numbers for tests which the diag-
nostic executive does not recognize, the requested in-
formation will not be displayed correctly and the scan
tool may display an error message. The same applies to
using the DTC trigger option in the Snapshot mode. If an
invalid DTC is entered, the scan tool will not trigger.
Failed Last Test
This message display indicates that the last diagnostic
test failed for the selected DTC. For type A, B and E
DTCs, this message will be displayed during subse-
quent ignition cycles until the test passes or DTCs are
cleared. For type C and type D DTCs, this message will
clear when the ignition is cycled.
Failed Since Clear
This message display indicates that the DTC has failed
at least once within the last 40 warm-up cycles since the
last time DTCs were cleared.
Failed This Ig. (Failed This Ignition)
This message display indicates that the diagnostic test
has failed at least once during the current ignition cycle.
This message will clear when DTCs are cleared or the
ignition is cycled.
History DTC
This message display indicates that the DTC has been
stored in memory as a valid fault. A DTC displayed as a
History fault may not mean that the fault is no longer
present. The history description means that all the con-
ditions necessary for reporting a fault have been met
(maybe even currently), and the information was stored
in the control module memory.
MIL Requested
This message display indicates that the DTC is currently
causing the MIL to be turned ON. Remember that only
type A B and E DTCs can request the MIL. The MIL re-
quest cannot be used to determine if the DTC fault con-
ditions are currently being experienced. This is because
the diagnostic executive will require up to three trips dur-
ing which the diagnostic test passes to turn OFF the
MIL.
Not Run Since CI (Not Run Since Cleared)
This message display indicates that the selected diag-
nostic test has not run since the last time DTCs were
cleared. Therefore, the diagnostic test status (passing
or failing) is unknown. After DTCs are cleared, this mes-
sage will continue to be displayed until the diagnostic
test runs.
Not Run This Ig. (Not Run This Ignition)
This message display indicates that the selected diag-
nostic test has not run during this ignition cycle.
Test Ran and Passed
This message display indicates that the selected diag-
nostic test has done the following:Passed the last test.
Run and passed during this ignition cycle.
Run and passed since DTCs were last cleared.
If the indicated status of the vehicle is “Test Ran and
Passed” after a repair verification, the vehicle is ready to
be released to the customer.
If the indicated status of the vehicle is “Failed This Igni-
tion” after a repair verification, then the repair is incom-
plete and further diagnosis is required.
Prior to repairing a vehicle, status information can be
used to evaluate the state of the diagnostic test, and to
help identify an intermittent problem. The technician can
conclude that although the MIL is illuminated, the fault
condition that caused the code to set is not present. An
intermittent condition must be the cause.
PRIMARY SYSTEM-BASED
DIAGNOSTICS
There are primary system-based diagnostics which
evaluate the system operation and its effect on vehicle
emissions. The primary system-based diagnostics are
listed below with a brief description of the diagnostic
function:
Oxygen Sensor Diagnosis
The fuel control oxygen sensor (O2S) is diagnosed for
the following conditions:
Few switch count (rich to lean or lean to rich).
Slow response (average transient time lean to rich or
rich to lean).
Response time ratio (ratio of average transient time
rich(lean) to lean(rich)).
Inactive signal (output steady at bias voltage approxi-
mately 450 mV).
Signal fixed high.
Signal fixed low.
The catalyst monitor heated oxygen sensor (HO2S) is
diagnosed for the following conditions:
Heater performance (current during IGN on).
Signal fixed low during steady state conditions or
power enrichment (hard acceleration when a rich mix-
ture should be indicated).
Signal fixed high during steady state conditions or de-
celeration mode (deceleration when a lean mixture
should be indicated).
Inactive sensor (output steady at approx. 438 mV).
If the O2S pigtail wiring, connector or terminal are dam-
aged, the entire O2S assembly must be replaced. Do
not attempt to repair the wiring, connector or terminals.
In order for the sensor to function properly, it must have
clean reference air provided to it. This clean air refer-
ence is obtained by way of the O2S wire(s). Any attempt
to repair the wires, connector or terminals could result in
ENGINE CONTROLS 1F–17
DAEWOO M-150 BL2
DIAGNOSTIC INFORMATION AND PROCEDURES
SYSTEM DIAGNOSIS
DIAGNOSTIC AIDS
If an intermittent problem is evident, follow the guide-
lines below.
Preliminary Checks
Before using this section you should have already per-
formed the “Euro On-Board Diagnostic (EOBD) System
Check.”
Perform a thorough visual inspection. This inspection
can often lead to correcting a problem without further
checks and can save valuable time. Inspect for the fol-
lowing conditions:
Engine Control Module (ECM) grounds for being
clean, tight, and in their proper location.
Vacuum hoses for splits, kinks, collapsing and proper
connections as shown on the Vehicle Emission Con-
trol Information label. Inspect thoroughly for any type
of leak or restriction.
Air leaks at the throttle body mounting area and the
intake manifold sealing surfaces.
Ignition wires for cracks, hardness, proper routing,
and carbon tracking.
Wiring for proper connections.
Wiring for pinches or cuts.
Diagnostic Trouble Code Tables
Do not use the Diagnostic Trouble Code (DTC) tables to
try and correct an intermittent fault. The fault must be
present to locate the problem.
Incorrect use of the DTC tables may result in the unnec-
essary replacement of parts.
Faulty Electrical Connections or Wiring
Most intermittent problems are caused by faulty electri-
cal connections or wiring. Perform a careful inspection
of suspect circuits for the following:
Poor mating of the connector halves.
Terminals not fully seated in the connector body.
Improperly formed or damaged terminals. All connec-
tor terminals in a problem circuit should be carefullyinspected, reformed, or replaced to insure contact
tension.
Poor terminal-to-wire connection. This requires re-
moving the terminal from the connector body.
Road Test
If a visual inspection does not find the cause of the prob-
lem, the vehicle can be driven with a voltmeter or a scan
tool connected to a suspected circuit. An abnormal volt-
age or scan tool reading will indicate that the problem is
in that circuit.
If there are no wiring or connector problems found and a
DTC was stored for a circuit having a sensor, except for
DTC P0171 and DTC P0172, replace the sensor.
Intermittent Malfunction Indicator Lamp
(MIL)
An intermittent Malfunction Indicator Lamp(MIL) with no
DTC present may be caused by the following:
Improper installation of electrical options such as
lights, two way radios, sound, or security systems.
MIL driver wire intermittently shorted to ground.
Fuel System
Some intermittent driveability problems can be attrib-
uted to poor fuel quality. If a vehicle is occasionally run-
ning rough, stalling, or otherwise performing badly, ask
the customer about the following fuel buying habits:
Do they always buy from the same source? If so, fuel
quality problems can usually be discounted.
Do they buy their fuel from whichever fuel station that
is advertising the lowest price? If so, check the fuel
tank for signs of debris, water, or other contamina-
tion.
IDLE LEARN PROCEDURE
Whenever the battery cables, the Engine Control Mod-
ule (ECM), or the fuse is disconnected or replaced, the
following idle learn procedure must be performed:
1. Turn the ignition ON for 10 seconds.
2. Turn the ignition OFF for 10 seconds.
ENGINE CONTROLS 1F–21
DAEWOO M-150 BL2
MULTIPLE ECM INFORMATION SENSOR DTCS SET
Circuit Description
The Engine Control Module (ECM) monitors various
sensors to determine engine operating conditions. The
ECM controls fuel delivery, spark advance, transaxle op-
eration, and emission control device operation based on
the sensor inputs.
The ECM provides a sensor ground to all of the sensors.
The ECM applies 5 volts through a pull-up resistor and
monitors the voltage present between the sensor and
the resistor to determine the status of the Engine Cool-
ant Temperature (ECT) sensor, the Intake Air Tempera-
ture (IAT) sensor. The ECM provides the Electric
Exhaust Gas Recirculation (EEGR) Pintle Position Sen-
sor, the Throttle Position (TP) sensor, the Manifold Ab-
solute Pressure (MAP) sensor, and the Fuel Tank
Pressure Sensor with a 5 volt reference and a sensor
ground signal. The ECM monitors the separate feed-
back signals from these sensors to determine their oper-
ating status.
Diagnostic Aids
Be sure to inspect the ECM and the engine grounds for
being secure and clean.
A short to voltage in one of the sensor circuits can cause
one or more of the following DTCs to be set: P0108,
P0113, P0118, P0123, P1106.If a sensor input circuit has been shorted to voltage, en-
sure that the sensor is not damaged. A damaged sensor
will continue to indicate a high or low voltage after the
affected circuit has been repaired. If the sensor has
been damaged, replace it.
An open in the sensor ground circuit between the ECM
and the splice will cause one or more of the following
DTCs to be set: P0108, P0113, P0118, P0123, P1106.
A short to ground in the 5 volt reference circuit or an
open in the 5 volt reference circuit between the ECM
and the splice will cause one or more of the following
DTCs to be set: P0107, P0112, P0117, P0122, P1107.
Check for the following conditions:
Inspect for a poor connection at the ECM. Inspect
harness connectors for backed-out terminals, im-
proper mating, broken locks, improperly formed or
damaged terminals, and poor terminal-to-wire con-
nection.
Inspect the wiring harness for damage. If the harness
appears to be OK, observe an affected sensor’s dis-
played value on the scan tool with the ignition ON and
the engine OFF while moving connectors and wiring
harnesses related to the affected sensors. A change
in the affected sensor’s displayed value will indicate
the location of the fault.
ENGINE CONTROLS 1F–29
DAEWOO M-150 BL2
Engine Cranks But Will Not Run (Cont’d)
StepActionValue(s)YesNo
42
1. Turn the ignition OFF.
2. Connect test light between fuel injector harness
connector 2 and battery positive.
3. Crank the engine.
4. Repeat step 2 and 3 for each of the remaining
fuel injectors.
Does the test light flash for all of the fuel injectors?
–
Go to Step 43Go to Step 46
43
Measure the resistance of each fuel injectors.
Is the resistance within the value specified.
Note: the resistance will increase slightly at higher
temperature.
13.75–15.25
ΩSystem OKGo to Step 44
44
Replace any of the fuel injectors with a resistance
out of specification.
Is the repair complete?
–
Go to Step 2
–
45
1. Inspect the fuse EF19 in engine fuse block.
2. Check for an open between the circuit from
terminal 2 of the three fuel injectors and terminal
87 of main relay.
Is the problem found?
–
Go to Step 48
Go to “Main
Relay Circuit
Check”
46
Measure the resistance between following terminals.
Terminal 1 of injector 1 connector and terminal 30
of ECM connector.
Terminal 1 of injector 2 connector and terminal 58
of ECM connector.
Terminal 1 of injector 3 connector and terminal 89
of ECM connector.
Does the resistance within the specified value?
0 ΩGo to Step 49Go to Step 47
47Repair the open fuel injector harness wire(s).
Is the repair complete?–Go to Step 2–
48Replace the fuse or repair the wiring as needed.
Is the repair complete?–Go to Step 2–
49Replace the ECM.
Is the repair complete?–Go to Step 2–
1F–30 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F030
NO MALFUNCTION INDICATOR LAMP
Circuit Description
When the ignition is turned ON, the Malfunction Indica-
tor Lamp (MIL) will be turned ON and remain ON until
the engine is running, if no Diagnostic Trouble Codes
(DTCs) are stored. Battery voltage is supplied through
the ignition switch directly to the MIL telltale. The Engine
Control Module (ECM) controls the MIL by providing a
ground path through the MIL control circuit to turn ON
the MIL.
Diagnostic Aids
An open ignition F16 fuse will cause the entire cluster to
be inoperative.Check the battery and ignition feed circuits for poor con-
nections if the MIL is intermittent.
Any circuitry, that is suspected as causing an intermit-
tent complaint, should be thoroughly checked for
backed-out terminals, improper mating, broken locks,
improperly formed or damaged terminals, poor terminal-
to-wiring connections or physical damage to the wiring
harness.
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–
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
ENGINE CONTROLS 1F–47
DAEWOO M-150 BL2
Ignition System Check (Cont’d)
StepActionValue(s)YesNo
21
Measure the voltage between the CKP sensor
connector terminal 2 and ground.
Is the voltage within the value specified?
0.95–1.10 VGo to Step 18Go to Step 22
22
Check the wire between the CKP sensor connector
terminal 2 and the ECM connector terminal 24 for an
open or short.
Is the problem found?
–
Go to Step 23Go to Step 11
23
Repair the wire between the CKP sensor connector
terminal 2 and the ECM connector terminal 24.
Is the repair complete?
–
System OK
–
24
1. Turn the ignition OFF.
2. Connect a test light between the EI system
ignition coil connector terminal 2 and ground.
3. Turn the ignition ON.
Is the test light on?
–
Go to Step 27Go to Step 25
25
Check for an open in the wiring between the EI
system ignition coil connector, terminal 1 and the
main relay connector terminal 87.
Is the problem found?
–
Go to Step 26
Go to “Main
Relay Circuit
Check”
26
Repair the open in the wiring between the EI system
ignition coil connector terminal 1 and the main relay
connector terminal 87.
Is the repair complete?
–
System OK
–
27
Check for a damage in the terminal of the EI system
ignition coil connector and repair as needed.
Is the repair complete?
–
System OK
–