p0172 DAEWOO MATIZ 2003 Service Repair Manual

1F – 2 ENGINE CONTROLS
DAEWOO M-150 BL2
DTC P0122 Throttle Position Sensor Low
Voltage 1F-76. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0123 Throttle Position Sensor High
Voltage 1F-80. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0131 Oxygen Sensor Low Voltage 1F-84. . . .
DTC P0132 Oxygen Sensor High Voltage 1F-88. . . .
DTC P0133 Oxygen Sensor No Activity 1F-90. . . . .
DTC P0137 Heated Oxygen Sensor Low
Voltage 1F-94. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0138 Heated Oxygen Sensor High
Voltage 1F-98. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0140 Heated Oxygen Sensor
No Activity 1F-100. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0141 Heated Oxygen Sensor
Heater Malfunction 1F-104. . . . . . . . . . . . . . . . . . . .
DTC P0171 Fuel Trim System Too Lean 1F-106. . . .
DTC P0172 Fuel Trim System Too Rich 1F-109. . . .
DTC P1230 Fuel Pump Relay Low Voltage 1F-114.
DTC P1231 Fuel Pump Relay High Voltage 1F-118.
DTC P0261 Injector 1 Low Voltage 1F-122. . . . . . . .
DTC P0262 Injector 1 High Voltage 1F-124. . . . . . . .
DTC P0264 Injector 2 Low Voltage 1F-126. . . . . . . .
DTC P0265 Injector 2 High Voltage 1F-128. . . . . . . .
DTC P0267 Injector 3 Low Voltage 1F-130. . . . . . . .
DTC P0268 Injector 3 High Voltage 1F-132. . . . . . . .
DTC P0300 Multiple Cylinder Misfire 1F-135. . . . . . .
DTC P0300 Multiple Cylinder Misfire 1F-139. . . . . . .
DTC P1320 Crankshaft Segment Period
Segment adaptation At Limit 1F-142. . . . . . . . . . . .
DTC P1321 Crankshaft Segment Period
Tooth Error 1F-144. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0327 Knock Sensor Circuit Fault 1F-146. . . .
DTC P0335 Magnetic Crankshaft Position
Sensor Electrical Error 1F-150. . . . . . . . . . . . . . . . .
DTC P0336 58X Crankshaft Position Sensor
No Plausible Signal 1F-152. . . . . . . . . . . . . . . . . . . .
DTC P0337 58X Crankshaft Position Sensor
No Signal 1F-154. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0341 Camshaft Position Sensor
Rationality 1F-156. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0342 Camshaft Position Sensor
No Signal 1F-158. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0351 Ignition Signal Coil A Fault 1F-160. . . . .
DTC P0352 Ignition Signal Coil B Fault 1F-162. . . . .
DTC P0353 Ignition Signal Coil C Fault 1F-164. . . . .
DTC P1382 Rough Road Data
Invalid (Non ABS) 1F-166. . . . . . . . . . . . . . . . . . . . .
DTC P1382 Rough Road Data Invalid (ABS) 1F-170
DTC P1385 Rough Road Sensor Circuit Fault
(Non ABS) 1F-174. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1385 Rough Road Sensor Circuit Fault
(ABS) 1F-178. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DTC P0400 Exhaust Gas Recirculation
Out Of Limit 1F-182. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1402 Exhaust Gas Recirculation
Blocked 1F-186. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1403 Exhaust Gas Recirculation
Valve Failure 1F-188. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0404 Exhaust Gas Recirculation
Opened 1F-192. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1404 Exhaust Gas Recirculation
Closed 1F-196. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0405 EEGR Pintle Position Sensor
Low Voltage 1F-200. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0406 EEGR Pintle Position Sensor
High Voltage 1F-204. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0420 Catalyst Low Efficiency 1F-208. . . . . . . .
DTC P0444 EVAP Purge Control Circuit
No Signal 1F-210. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0445 EVAP Purge Control Fault 1F-214. . . . .
DTC P0462 Fuel Level Sensor Low Voltage 1F-218.
DTC P0463 Fuel Level Sensor High Voltage 1F-222
DTC P0480 Low Speed Cooling Fan Relay
Circuit Fauit (Without A/C) 1F-226. . . . . . . . . . . . . .
DTC P0480 Low Speed Cooling Fan Relay
Circuit Fauit (With A/C) 1F-230. . . . . . . . . . . . . . . . .
DTC P0481 High Speed Cooling Fan Relay
Circuit Fauit (Without A/C) 1F-234. . . . . . . . . . . . . .
DTC P0481 High Speed Cooling Fan Relay
Circuit Fauit (With A/C) 1F-238. . . . . . . . . . . . . . . . .
DTC P0501 Vehicle Speed No Signal
(M/T Only) 1F-242. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1505 Idle Air Control Valve (IACV)
Error 1F-246. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1535 Evaporator Temperature Sensor
High Voltage 1F-250. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1536 Evaporator Temperature Sensor
Low Voltage 1F-252. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1537 A/C Compressor Relay High
Voltage 1F-254. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1538 A/C Compressor Relay Low
Voltage 1F-256. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0562 System Voltage (Engine Side)
Too Low 1F-258. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0563 System Voltage (Engine Side)
Too High 1F-260. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0601 Engine Control Module Chechsum
Error 1F-262. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0604 Engine Control Module Internal/
External RAM Error 1F-263. . . . . . . . . . . . . . . . . . . .
DTC P0605 Engin Control Module NMVY
Write Error 1F-264. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1610 Main Relay High Voltage 1F-266. . . . . .
DTC P1611 Main Relay Low Voltage 1F-268. . . . . . .

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–19
DAEWOO M-150 BL2
Euro On-Board Diagnostic (EOBD) System Check
StepActionValue(s)YesNo
1
1. Turn the ignition ON with the engine OFF.
2. Observe the Malfunction Indicator Lamp (MIL).
Is the MIL on?
–
Go to Step 2
Go to “No
Malfunction
Indicator
Lamp”
2
1. Turn the ignition OFF.
2. Install the scan tool.
3. Turn the ignition ON.
4. Attempt to display the Engine Control Module
(ECM) engine data with the scan tool.
Does the scan tool display the ECM engine data?
–
Go to Step 3Go to Step 8
3
1. Using the scan tool output test function, select the
MIL lamp control and command the MIL off.
2. Observe the MIL.
Does the MIL turn off?
–
Go to Step 4
Go to
“Malfunction
Indicator Lamp
on Steady”
4
Attempt to start the engine.
Does the engine start and continue to run?
–
Go to Step 5
Go to “Engine
Cranks But
Will Not Run”
5Select DISPLAY DTC with the scan tool.
Are any Diagnostic Trouble Codes stored?–Go to Step 6Go to Step 7
6
Check the display for DTCs P0107, P0108, P0113,
P0118, P0122, P0123, P0172, P1392.
Are two or more of the following DTCs stored?
–
Go to “Multiple
ECM
Information
Sensor DTCs
Set”
Go to
applicable DTC
table
7
Compare the ECM data values displayed on the
scan tool to the typical engine scan data values.
Are the displayed values normal or close to the
typical values?
–Go to “ECM
Output
Diagnosis”Go to indicated
component
system check
8
1. Turn the ignition OFF and disconnect the ECM.
2. Turn the ignition ON with the engine OFF.
3. Check the serial data circuit for an open, short to
ground, or short to voltage. Also check the Data
Link Connector (DLC) ignition feed circuit for an
open or short to ground, and check the DLC
ground circuits for an open.
Is a problem found?
–
Go to Step 9Go to Step 10
9
Repair the open, short to ground, or short to voltage
in the serial data circuit or the DLC ignition feed
circuit.
Is the repair complete?
–
System OK
–
10
1. Attempt to reprogram the ECM.
2. Attempt to display the ECM data with the scan
tool.
Does the scan tool display ECM engine data?
–
Go to Step 2Go to Step 11
11Replace the ECM.
Is the repair complete?–System OK–

ENGINE CONTROLS 1F – 55
DAEWOO M-150 BL2
DIAGNOSTIC TROUBLE CODE DIAGNOSIS
CLEARING TROUBLE CODES
Notice: To prevent Engine Control Module (ECM) dam-
age, the key must be OFF when disconnecting or recon-
necting the power to the ECM (for example battery
cable, ECM pigtail connector, ECM fuse, jumper cables,
etc.).When the ECM sets a Diagnostic Trouble Code
(DTC), the Malfunction Indicator Lamp (MIL) lamp will
be turned on only for type A, B and E but a DTC will be
stored in the ECM’s memory for all types of DTC. If theproblem is intermittent, the MIL will go out after 10 sec-
onds if the fault is no longer present. The DTC will stay
in the ECM’s memory until cleared by scan tool. Remov-
ing battery voltage for 10 seconds will clear some stored
DTCs.
DTCs should be cleared after repairs have been com-
pleted. Some diagnostic tables will tell you to clear the
codes before using the chart. This allows the ECM to set
the DTC while going through the chart, which will help to
find the cause of the problem more quickly.
DIAGNOSTIC TROUBLE CODES
DTCFunctionError TypeIlluminate MIL
P0107Manifold Absolute Pressure Sensor Low VoltageAYES
P0108Manifold Absolute Pressure Sensor High voltageAYES
P0112Intake Air Temperature Sensor Low VoltageEYES
P0113Intake Air Temperature Sensor High voltageEYES
P0117Engine Coolant Temperature Sensor Low VoltageAYES
P0118Engine Coolant Temperature Sensor High voltageAYES
P0122Throttle Position Sensor Low VoltageAYES
P0123Throttle Position Sensor Hig voltageAYES
P0131Oxygen Sensor Low VoltageAYES
P0132Oxygen Sensor High VoltageAYES
P0133Oxygen Sensor No ActivityEYES
P0137Heated Oxygen Sensor Low VoltageEYES
P0138Heated Oxygen Sensor high voltageEYES
P0140Heated Oxygen Sensor No ActivityEYES
P0141Heated Oxygen Sensor Heater MalfuctionEYES
P0171Fuel Trim System Too LeanEYES
P0172Fuel Trim System Too RichEYES
P1230Fuel Pump Relay Low VoltageAYES
P1231Fuel Pump Relay High VoltageAYES
P0261Injector 1 Low VoltageAYES
P0262Injector 1 high voltageAYES
P0264Injector 2 Low VoltageAYES
P0265Injector 2 high voltageAYES
P0267Injector 3 Low VoltageAYES
P0268Injector 3 high voltageAYES
P0300Multifle Cylinder MisfireA/EBLINKING/ON
P1320Crankshatft Segment Period Segment Adaptation At LimitEYES
P1321Crankshatft Segment Period Tooth ErrorEYES
P0327Knock Sensor Circuit FaultEYES
P0335Magnetic Crankshaft Position Sensor Electrical ErrorEYES

ENGINE CONTROLS 1F–109
DAEWOO M-150 BL2
DIAGNOSTIC TROUBLE CODE (DTC) – P0172 FUEL TRIM SYSTEM TOO RICH
System Description
To provide the best possible combination of driveability,
fuel economy, and emission control, a Closed Loop air/
fuel metering system is used. While in Closed Loop, the
Engine Control Module (ECM) monitors the oxygen sen-
sor (O2S) signal voltage and adjusts fuel delivery based
on signal voltage. A change made to fuel delivery will be
indicated by the long and short term fuel trim values
which can be monitored with the scan tool. Ideal fuel trim
values are around 128 (0%). If the O2S signal is indicat-
ing a lean condition, the ECM will add fuel resulting in
fuel trim values above 128 (0% to 100%). If a rich condi-
tion is detected, the fuel trim values will be below 128
(0% to –100%), indicating that the ECM is reducing the
amount of fuel delivered. If exhaust emissions reach an
excessive level due to a lean or rich condition, a fuel trim
Diagnostic Trouble Code (DTC) is set.
Conditions for Setting the DTC

No intrusive tests active.

DTCs P0106, P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0131, P0132, P0133,
P0134, P0137, P0138, P1167, P1171, P0300,
P0336, P0337, P0341, P0342, P0402, P0404,
P1404, P0405, P0406, P0443, P0506, and P0507are
not set.

The average of short term fuel trim value is greater
than or equal to 120.

Throttle Position (TP) is less than 95%.

Engine speed is between 700 and 6000 rpm.

Barometric Pressure (BARO) is greater than 90.0
kPa (10.4 psi).

Coolant temperature is between 80°C (176°F) and
11 5°C (239°F).

Manifold Absolute Pressure (MAP) is more than 70
kPa (10.2 psi).

System is in closed loop.

Adaptive index is ready.
Action Taken when the DTC Sets

Emission related.
“Armed” after two trip with a fail.

“Disarmed” after one trip with a pass.

MIL on if failure is detected in three consecutive trips.

Stores a History DTC on the third consecutive with a
fail (The DTC will be armed after the second fail).

Stores a Freeze Frame on the third consecutive trip
with a fail (if empty).
Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.

A history DTC will clear after 40 consecutive warm up
cycles without a fault.

DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
Important: After repairs, use the scan tool Fuel Trim
Reset function to reset the long-term fuel trim to 128
(0%).
Check for poor connection at the ECM. Inspect the har-
ness connectors for the following conditions:

Backed-out terminals.

Improper mating.

Broken locks.

Improperly formed.

Damaged terminals.

Poor terminal-to-wire connection.
Inspect the wiring harness for damage. If the harness
appears to be OK, observe the O2S display on the scan
tool while moving the connectors and the wiring harness
related to the engine harness. A change in the display
will indicate the location of the fault.
If a DTC P1404 is also set, check the 5 volt reference
circuits for a short to voltage.
Check for a restricted exhaust system.
A shorted 5 volt reference circuit may cause a DTC
P0172 to set. Check the 5 volt reference sensors for ab-
normal readings.

1F–110 ENGINE CONTROLS
DAEWOO M-150 BL2
DTC P0172 – Fuel Trim System Too Rich
StepActionValue(s)YesNo
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
Install the scan tool to the Data Link Connector
(DLC).
Turn the ignition ON.
Are any component related Diagnostic Trouble
Codes (DTCs) set?
–Go to
Applicable DTC
table
Go to Step 3
3
1. With the engine running, operate the vehicle until
the LOOP STATUS indicates closed.
Is the Long Term Fuel Trim value above the
specified value?
30%Go to Step 4Go 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 above the
specified value while operating under the specified
conditions?
30%Go to Step 21Go to Step 5
5
Visually/physically check the air cleaner filter for
excessive dirt or being plugged and repair as
needed.
Is the repair complete?
–
Go to Step 21Go to Step 6
6
Visually/physically check the air intake system for
collapsed or restricted and repair as needed.
Is the repair complete?
–
Go to Step 21Go to Step 7
7
Inspect the throttle body inlet for damaged or foreign
objects which may partially block the airflow and
repair as needed.
Is the repair complete?
–
Go to Step 21Go to Step 8
8
1. Turn the ignition OFF.
2. Inspect the throttle bore, throttle plate and Idle Air
Control (IAC) passages for clocking and foreign
objects and repair as needed.
Is the repair complete?
–
Go to Step 21Go to Step 9
9
Start the engine with the vehicle in park or neutral
and A/C off and note the idle quality.
Is a low or unsteady idle being experienced?
–
Go to Step 10Go to Step 12
10Idle the engine.
Are the IAC counts below the specified value?
100Go to Step 12Go to Step 11
11
1. Turn the ignition OFF.
2. Disconnect the Manifold Absolute Pressure
(MAP) sensor electrical connector.
3. Start the engine.
4. Operate the vehicle in Closed Loop while
monitoring the Long Term Fuel Trim value.
Does the Long Term Fuel Trim value increase above
the specified value?
30%Go to Step 20Go to Step 12

ENGINE CONTROLS 1F–111
DAEWOO M-150 BL2
DTC P0172 – Fuel Trim System Too Rich (Cont’d)
StepActionValue(s)YesNo
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 21Go to Step 13
13
1. Disconnect the vacuum hose from the fuel
pressure regulator and inspect the hose for the
presence of fuel.
2. If fuel is presence in the vacuum hose, replace
the fuel pressure regulator.
Is the repair complete?
–
Go to Step 21Go to Step 14
14
1. Turn the ignition ON.
2. Slowly press the acceleration pedal.
Does the Throttle Position (TP) sensor display
increase steady and evenly from its minimum
voltage at closed throttle to its maximum voltage at
Wide-Open Throttle (WOT).
–
Go to Step 15Go to Step 19
15
1. Perform the Fuel System Diagnosis.
2. If the table isolate a problem, repair as needed.
Is the repair complete?
–
Go to Step 21Go to Step 16
16
1. Perform the Evaporative Emission (EVAP)
Control System Diagnosis.
2. If the table isolate a problem, repair as needed.
Is the repair complete?
–
Go to Step 21Go to Step 17
17
1. Perform the Fuel Injector balance Test.
2. If the table isolate a problem, repair as needed.
Is the repair complete?
–
Go to Step 21Go to Step 18
18
1. Remove the Oxygen Sensor (O2S)
2. Visually/physically inspect the O2S for silicone
contamination.
3. Note: this will be indicated by a powdery white
deposit on the portion of the O2S exposed to the
exhaust stream.
4. If contamination is present on the O2S, find the
source and repair as needed.
Is the repair complete?
–
Go to Step 21
Go to
“Diagnostic
Aids”
19
1. Check the TP sensor mounting screws.
2. If they are too loose or missing tighten or replace
them as needed.
3. If the screws are OK, replace the TP sensor.
Is the repair complete?
–
Go to Step 21
–
20
1. Turn the ignition OFF.
2. Replace the MAP sensor.
Is the repair complete?
–
Go to Step 21
–

1F–112 ENGINE CONTROLS
DAEWOO M-150 BL2
DTC P0172 – Fuel Trim System Too Rich (Cont’d)
StepActionValue(s)YesNo
21
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 21Go to Step 2
22
Check if any additional DTCs are set.
Are any DTCs displayed that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK

1F–208 ENGINE CONTROLS
DAEWOO M-150 BL2
DIAGNOSTIC TROUBLE CODE (DTC) – P0420 CATALYST LOW EFFICIENCY
Circuit Description
In order to control exhaust emissions of Hydrocarbons
(HC), Carbon Monoxide (CO) and Nitrogen Oxide
(NOx), a Three-Way Catalytic Converter (TWC) is used.
The catalyst within the converter promotes a chemical
reaction which oxidizes the HC and CO present in the
exhaust gas, converting them into harmless water vapor
and carbon dioxide, it also reduces NOx, converting it
into nitrogen. The catalytic converter also has the ability
to store oxygen. The Engine Control Module (ECM) has
the capability to monitor this process using a Heated
Oxygen Sensor (HO2S) located in the exhaust stream
past the TWC. The HO2S produces an output signal
which indicates the oxygen storage capacity of the cata-
lyst; this in turn indicates the catalyst’s ability to convert
exhaust emissions effectively. The ECM monitors the
catalyst efficiency by first allowing the catalyst to heat
up, waiting for a stabilization period while the engine is
idling, and then adding and removing fuel while monitor-
ing the reaction of the HO2S. When the catalyst is func-
tioning properly, the HO2S response to the extra fuel is
slow compared to the Oxygen Sensor (O2S). When the
HO2S response is close to that of the O2S, the Oxygen
storage capability or efficiency of the catalyst is consid-
ered to be bad, and the Malfunction Indicator Lamp
(MIL) will illuminate.
Conditions for Setting the DTC

Oxygen Sensor Capacity test condition:

Closed loop stoichiometry.

Engine is running more than 300 seconds.

Airflow is between 25~50kg/h.

Engine Coolant Temperature (ECT) is more than
70°C(176°F) .

Engine speed between 2,400rpm and 3,000rpm.

Vehicle speed is between 64km/h(28.6mph) and
80km/h(49.7mph).
Note: Test is aborted for this idle if:

Change in engine speed is greater than 80 rpm.

A/C status changed.

Cooling fan status changed.
Insufficient air/fuel shift.

DTC(s) P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0125, P0131, P0132, P0133,
P1133, P0134, P1134, P0137, P0138, P0140,
P0141, P1167, P1171, P0171, P0172, P0201,
P0202, P0203, P0204, P0300, P0336, P0337,
P0341, P0342, P0351, P0352, P0402, P0404,
P0405, P0406, P0506, P0507, and P0562 are NOT
SET.
Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.

The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.

A history DTC is stored.
Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.

A history DTC will clear after 40 consecutive warm-up
cycles without a fault.

DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
The catalyst test may abort due to a change in the en-
gine load. Do not change the engine load (i.e. A/C, cool-
ant fan, heater motor) while a catalyst test is in progress.
An intermittent problem may be caused by a poor con-
nection, rubbed-through wire insulation, or a wire that is
broken inside the insulation.
Any circuitry, that is suspected as causing the intermit-
tent complaint, should be thoroughly checked for the fol-
lowing conditions:

Backed-out terminals

Improper mating

Broken locks

Improperly formed

Damaged terminals

Poor terminal-to-wire connection.

1F–246 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F070
DIAGNOSTIC TROUBLE CODE (DTC) 0505
IDLE AIR CONTROL VALVE (IACV) CIRCUIT FAULT
Circuit Description
The Engine Control Module (ECM) controls the air en-
tering into the engine with an Idle Air Control (IAC)
Valve. To increase the idle rpm, the ECM commands the
pintle inside the IAC valve away from the throttle body
seat. This allows more air to bypass through the throttle
blade. To decrease the rpm the ECM commands the
pintle towards the throttle body seat. This reduces the
amount of air bypassing the throttle blade. A scan tool
will read the IAC valve pintle position in counts. The
higher the counts, the more air that is allowed to bypass
the throttle blade. This Diagnostic Trouble Code (DTC)
determines if a low idle condition exists as defined as
100 rpm below the desired idle rpm.
Conditions for Setting the DTC

No intrusive tests are active.

DTC(s) P0106, P0107, P0108, P0112, P0113,
P0117, P0118, P0122, P0123, P0131, P0132,
P0133, P1133, P1134, P0171, P1171, P0172, P0201,
P0202, P0203, P0204, P0300, P0336, P0337,
P0341, P0342, P0351, P0352, P0402, P0404,
P1404, P0405, P0406, P0443, and P0502 are not
set.

Engine is running more than 60 seconds.

Barometric Pressure (BARO) is greater than 72 kPa
(10.4 psi).

Engine Coolant Temperature (ECT) is greater than
60C (140F).

Ignition voltage is between 11 and 16 volts.

The Intake Air Temperature (IAT) is greater than
–20C (–4F).

Manifold Absolute Pressure is less than 60 kPa (8.7
psi).
IAC valve is controlled fully opened.

All of the above must be met for greater than 5 sec-
onds.
Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.

The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.

A history DTC is stored.
Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.

A history DTC will clear after 40 consecutive warm-up
cycles without a fault.

DTC(s) can be cleared by using the scan tool.

Disconnecting the ECM battery feed for more than 10
seconds.
Diagnostic Aids
Inspect the IAC valve electrical connection for proper
mating.
Inspect the wiring harness for damage.
Inspect the throttle stop screw for signs of tampering.
Inspect the throttle linkage for signs of binding or exces-
sive wear.
A slow or unstable idle may be caused by one of the fol-
lowing conditions:

Fuel system too rich or too lean.

Foreign material in the throttle body bore or in the air
induction system.

A leaking or restricted intake manifold.