2004 DAEWOO LACETTI p0420

1F – 2IENGINE CONTROLS
DAEWOO V–121 BL4
TROUBLE CODE DIAGNOSIS
(1.4L/1.6L DOHC) 1F–111. . . . . . . . . . . . . . . . . . . . . . . .
Clearing Trouble Codes 1F–111. . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Codes (1.4L/1.6L DOHC) 1F–111.
DTC P0107 Manifold Absolute Pressure Sensor
Low Voltage 1F–114. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0108 Manifold Absolute Pressure Sensor
High Voltage 1F–117. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0112 Intake Air Temperature Sensor Low
Voltage 1F–120. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0113 Intake Air Temperature Sensor High
Voltage 1F–122. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0117 Engine Coolant Temperature
Sensor Low Voltage 1F–125. . . . . . . . . . . . . . . . . . . .
DTC P0118 Engine Coolant Temperature
Sensor High Voltage 1F–128. . . . . . . . . . . . . . . . . . . .
DTC P0122 Throttle Position Sensor Low
Voltage 1F–131. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0123 Throttle Position Sensor High
Voltage 1F–134. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0131 Front Heated Oxygen Sensor Low
Voltage 1F–137. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0132 Front Heated Oxygen Sensor High
Voltage 1F–140. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0133 Front Heated Oxygen Sensor No
Activity 1F–142. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0135 Front Heated Oxygen Sensor Heater
Circuit Not Functioning 1F–145. . . . . . . . . . . . . . . . . .
DTC P0137 Rear Heated Oxygen Sensor Low
Voltage 1F–148. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0138 Rear Heated Oxygen Sensor High
Voltage 1F–151. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0140 Rear Heated Oxygen Sensor No
Activity 1F–153. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0141 Rear Heated Oxygen Sensor Heater
Malfunction 1F–156. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0171 Fuel Trim System Too Lean 1F–158. . . .
DTC P0172 Fuel Trim System Too Rich 1F–162. . . . .
DTC P0222 Main Throttle Idle Actuator (MTIA)
Low Voltage 1F–165. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0223 Main Throttle Idle Actuator (MTIA)
High Voltage 1F–168. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0261 Injector 1 Low Voltage 1F–171. . . . . . . . .
DTC P0262 Injector 1 High Voltage 1F–173. . . . . . . .
DTC P0264 Injector 2 Low Voltage 1F–175. . . . . . . . .
DTC P0265 Injector 2 High Voltage 1F–177. . . . . . . .
DTC P0267 Injector 3 Low Voltage 1F–179. . . . . . . . .
DTC P0268 Injector 3 High Voltage 1F–181. . . . . . . .
DTC P0270 Injector 4 Low Voltage 1F–183. . . . . . . . .
DTC P0271 Injector 4 High Voltage 1F–185. . . . . . . . DTC P0300 Multiple Cylinder Misfire(Catalyst
Damage) 1F–188. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0300 Multiple Cylinder Misfire(Increase
Emission) 1F–192. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0327 Knock Sensor Circuit Fault
(1.4L DOHC) 1F–195. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0327 Knock Sensor Circuit Fault
(1.6L DOHC) 1F–198. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0335 Magnetic Crankshaft Position
Sensor Electrical Error 1F–201. . . . . . . . . . . . . . . . . .
DTC P0336 58X Crankshaft Position Sensor
No Plausible Signal 1F–204. . . . . . . . . . . . . . . . . . . .
DTC P0337 58X Crankshaft Position Sensor
No Signal 1F–207. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0341 Camshaft Position Sensor
Rationality 1F–210. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0342 Camshaft Position Sensor Signal 1F–212
DTC P0351 Ignition Signal Coil A Fault 1F–214. . . . .
DTC P0352 Ignition Signal Coil B Fault 1F–216. . . . .
DTC P0400 Exhaust Gas Recirculation Out
Of Limit 1F–218. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0404 Exhaust Gas Recirculation
Opened 1F–221. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0405 EGR Pintle Position Sensor Low
Voltage 1F–224. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0406 EGR Pintle Position Sensor High
Voltage 1F–227. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0420 Catalyst Low Efficiency 1F–230. . . . . . . .
DTC P0444 EVAP Purge Control Circuit No
Signal 1F–232. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0445 EVAP Purge Control Circuit Fault 1F–235
DTC P0462 Fuel Level Sensor Low Voltage
(1.6L DOHC Only) 1F–238. . . . . . . . . . . . . . . . . . . . .
DTC P0463 Fuel Level Sensor High Voltage
(1.6L DOHC Only) 1F–241. . . . . . . . . . . . . . . . . . . . .
DTC P0480 Low Speed Cooling Fan Relay
Circuit Fault (1.4L DOHC) 1F–245. . . . . . . . . . . . . . .
DTC P0480 Low Speed Cooling Fan Relay
Circuit Fault (1.6L DOHC) 1F–248. . . . . . . . . . . . . . .
DTC P0481 High Speed Cooling Fan Relay
Circuit Fault (1.4L DOHC) 1F–251. . . . . . . . . . . . . . .
DTC P0481 High Speed Cooling Fan Relay
Circuit Fault (1.6L DOHC) 1F–254. . . . . . . . . . . . . . .
DTC P0501 Vehicle Speed No Signal
(M/T Only) 1F–257. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0510 Throttle Position Switch Circuit Fault
(1.4L DOHC) 1F–260. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0510 Throttle Position Switch Circuit
Fault (1.6L DOHC) 1F–262. . . . . . . . . . . . . . . . . . . . .
DTC P0532 A/C Pressure Sensor Low Voltage 1F–264
DTC P0533 A/C Pressure Sensor High
Voltage 1F–267. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1F – 4IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0203 Injector 3 Circuit Fault 1F–414. . . . . . . . .
DTC P0204 Injector 4 Circuit Fault 1F–417. . . . . . . . .
DTC P0300 Multiple Cylinder Misfire Detected 1F–421
DTC P0301 Cylinder 1 Misfire 1F–426. . . . . . . . . . . . .
DTC P0302 Cylinder 2 Misfire 1F–431. . . . . . . . . . . . .
DTC P0303 Cylinder 3 Misfire 1F–436. . . . . . . . . . . . .
DTC P0304 Cylinder 4 Misfire 1F–441. . . . . . . . . . . . .
DTC P0317 Rough Road Sensor Source Not
Detected 1F–445. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0325 Knock Sensor Internal
Malfunction 1F–447. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0327 Knock Sensor Circuit Fault 1F–449. . . . .
DTC P0336 58X Crank Position Extra/Missing
Pulses 1F–452. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0337 58X Crank Position Sensor No
Signal 1F–455. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0341 Camshaft Position Sensor
Rationality 1F–458. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0342 Camshaft Position Sensor No
Signal 1F–461. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0351 Ignition Control Circuit A Fault
(Cylinder 1 and 4) 1F–464. . . . . . . . . . . . . . . . . . . . . .
DTC P0352 Ignition Control Circuit B Fault
(Cylinder 2 and 3) 1F–466. . . . . . . . . . . . . . . . . . . . . .
DTC P0401 Exhaust Gas Recirculation Insufficient
Flow 1F–468. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0402 Exhaust Gas Recirculation Excessive
Flow 1F–470. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0404 Exhaust Gas Recirculation Open
Valve Position Error 1F–474. . . . . . . . . . . . . . . . . . . .
DTC P0405 Exhaust Gas Recirculation Pintle
Position Low Voltage 1F–478. . . . . . . . . . . . . . . . . . .
DTC P0406 Exhaust Gas Recirculation Pintle
Position High Voltage 1F–481. . . . . . . . . . . . . . . . . . .
DTC P0420 Catalyst Oxygen Sensor Low
Efficiency 1F–484. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0443 Evaporative Emission System Purge
Solenoid Control Circuit 1F–486. . . . . . . . . . . . . . . . .
DTC P0461 Fuel Level Struck 1F–489. . . . . . . . . . . . .
DTC P0462 Fuel Level Low Voltage 1F–492. . . . . . . .
DTC P0463 Fuel Level High Voltage 1F–495. . . . . . .
DTC P0502 Vehicle Speed Sensor No Signal
(Engine Side) 1F–498. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0506 Idle Speed RPM Lower Than Desired
Idle Speed 1F–501. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0507 Idle Speed RPM Higher Than Desired
Idle Speed 1F–504. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0532 A/C Pressure Sensor Low Voltage 1F–507
DTC P0533 A/C Pressure Sensor High
Voltage 1F–510. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DTC P0562 System Voltage Too Low
(Engine Side) 1F–513. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0563 System Voltage Too High
(Engine Side) 1F–515. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0601 ECM Checksum Fault
(Engine Side) 1F–517. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P0602 ECM Reprogrom Error 1F–518. . . . . . . .
DTC P0607 Lower Power Counter Error 1F–519. . . .
DTC P0700 Transaxle Control Module
Malfunction 1F–520. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1106 Manifold Abosolute Pressure
Intermittent High Voltage 1F–522. . . . . . . . . . . . . . . .
DTC P1107 Manifold Abosolute Pressure
Intermittent Low Voltage 1F–524. . . . . . . . . . . . . . . .
DTC P1111 Intake Air Temperature Intermittent
High Voltage 1F–526. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1112 Intake Air Temperature Intermittent
Low Voltage 1F–529. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1114 Engine Coolant Temperature
Intermittent Low Voltage 1F–531. . . . . . . . . . . . . . . .
DTC P1115 Engine Coolant Temperature
Intermittent High Voltage 1F–533. . . . . . . . . . . . . . . .
DTC P1121 Throttle Position Sensor Intermittent
High Voltage 1F–535. . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1122 Throttle Position Sensor Intermittent
Low Voltage 1F–537. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1133 Front Heated Oxyzen Sensor
(HO2S1) Too Few Transitions 1F–539. . . . . . . . . . .
DTC P1134 Front Heated Oxyzen Sensor
(HO2S1) Transitions Ratio 1F–543. . . . . . . . . . . . . .
DTC P1167 Front Heated Oxyzen Sensor
(HO2S1) Rich in Decel Fuel Cutoff (DFCO) 1F–546
DTC P1171 Fuel Trim System Lean During Power
Enrichment 1F–548. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1336 58X Crank Position Tooth Error Not
Learned 1F–550. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1391 G Sensor Rough Road Rationality 1F–552
DTC P1392 G Sensor Rough Low Voltage 1F–555. .
DTC P1393 G Sensor Rough High Voltage 1F–558. .
DTC P1396 ABS WSS Signal Variation 1F–561. . . . .
DTC P1397 ABS WSS No Signal 1F–563. . . . . . . . . .
DTC P1404 Exhaust Gas Recirculation Closed
Valve Pintle Error 1F–565. . . . . . . . . . . . . . . . . . . . . .
DTC P1601 SPI Communications Between
ECM and TCM 1F–568. . . . . . . . . . . . . . . . . . . . . . . .
DTC P1607 Lower Power Counter Reset 1F–569. . .
DTC P1626 Immobilizer No Response 1F–570. . . . . .
DTC P1631 Immobilizer Invalid Response 1F–571. .
DTC P1650 SPI Communications Between Error
with SIDM Chip 1F–572. . . . . . . . . . . . . . . . . . . . . . . .
DTC P1655 SPI Communications Between Error
with PSVI Chip 1F–573. . . . . . . . . . . . . . . . . . . . . . . .

1F – 112IENGINE CONTROLS
DAEWOO V–121 BL4
DTCIlluminate MIL Error
Type Function
P0300Multiple Cylinder Misfire (Increase Emission)EYES
P0327Knock Sensor Circuit Fault (1.4L DOHC)CnlNO
P0327Knock Sensor Circuit Fault (1.6L DOHC)EYES
P0335Magnetic Crankshaft Position Sensor Electrical ErrorEYES
P033658X Crankshaft Position Sensor Extra/missing PulseEYES
P033758X Crankshaft Sensor No SignalEYES
P0341Camshaft Position Sensor RationalityEYES
P0342Camshaft Position Sensor No SignalEYES
P0351Ignition Signal Coil A FaultAYES
P0352Ignition Signal Coil B FaultAYES
P0400Exhaust Gas Recirculation Out of LimitEYES
P0404Exhaust Gas Recirculation (EGR) PpendEYES
P0405EGR Pintle Position Sensor Low VoltageEYES
P0406EGR Pintle Position Sensor High voltageEYES
P0420Catalyst Low EfficiencyAYES
P0444EVAP Purge Control Circuit No SignalEYES
P0445EVAP Purge Control Circuit FaultEYES
P0462Fuel Level Sensor Low Voltage (1.6L DOHC Only)CnlNO
P0463Fuel Level Sensor High Voltage (1.6L DOHC Only)CnlNO
P0480Low Speed Cooling Fan Relay Circuit Fault (1.4L DOHC)EYES
P0480Low Speed Cooling Fan Relay Circuit Fault (1.6L DOHC)CnlNO
P0481High Speed Cooling Fan Relay High Voltage (1.4L DOHC)EYES
P0481High Speed Cooling Fan Relay High Voltage (1.6L DOHC)CnlNO
P0501Vehicle Speed No Signal (M/T Only)AYES
P0510Throttle Positon Switch Circuit Fault (1.4L DOHC)CnlNO
P0510Throttle Positon Switch Circuit Fault (1.6L DOHC)AYES
P0532A/C Pressure Sensor Low VoltageCnlNO
P0533A/C Pressure Sensor High VoltageCnlNO
P0562System Voltage (Engine Side) Too LowCnlNO
P0563System Voltage (Engine Side) Too HighCnlNO
P0601Engine Control Module Checksum ErrorEYES
P0604Engine Control Module RAM ErrorEYES
P0605Engine Control Module INMVY Write ErrorEYES
P0656Fuel Level Gauge High Circuit FaultCnlNO
P1181Variable Intake Manifold Solenoid Low VoltageEYES
P1182Variable Intake Manifold Solenoid High VoltageEYES
P1230Fuel Pump Relay Low Voltage (1.4L DOHC)CnlNO
P1230Fuel Pump Relay Low Voltage (1.6L DOHC)AYES
P1231Fuel Pump Relay High Voltage (1.4L DOHC)CnlNO
P1231Fuel Pump Relay High Voltage (1.6L DOHC)AYES
P1320Crankshaft Segment Period Segment Adaptation At LimitEYES

1F – 230IENGINE CONTROLS
DAEWOO V–121 BL4
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 cat-
alyst 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 oxy-
gen storage capacity of the catalyst; this in turn indicates
the catalyst’s ability to convert exhaust emissions effec-
tively. The ECM monitors the catalyst efficiency by first al-
lowing the catalyst to heat up, waiting for a stabilization pe-
riod while the engine is idling, and then adding and
removing fuel while monitoring the reaction of the HO2S.
When the catalyst is functioning properly, the HO2S re-
sponse 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 considered to be bad, and the Malfunction
Indicator Lamp (MIL) will illuminate.
Conditions for Setting the DTC
S Closed loop stoichiometry.
S Engine Coolant Temperature (ECT) is more than
75°C (167°F) . (1.4L DOHC)
S Engine Coolant Temperature (ECT) is more than
70°C (158°F) . (1.6L DOHC)
S Engine speed between 1,766rpm and 2,368rpm.
(1.4L DOHC)
S Engine speed between 1,760rpm and 2,530rpm.
(1.6L DOHC)
S Vehicle speed is between 47km/h (29.2mph) and
80km/h (49.7mph). (1.4L DOHC)
S Vehicle speed is between 60km/h (37.3mph) and
76km/h (47.2mph). (1.6L DOHC)
S The manifold absolute pressure is greater than 70
kpa. (1.4L DOHC)S The manifold absolute pressure is greater than 76
kpa. (1.6L DOHC)
S Activity of the heated oxygen sensor excited by
lambda controller stimuli higher than a threshold.
S DTC(s) P0107, P0108, P0117, P0118, P0122,
P0123, P0131, P0132, P0133, P0137, P0138,
P0140, P0141, P0171, P0172, P0300, P0336,
P0337, P0341, P0342, P0351, P0352, P0404,
P0405, P0405 and P0562 are not sets.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.
S The ECM will record operating conditions at the
time the diagnostic fail. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
The catalyst test may abort due to a change in the engine
load. Do not change the engine load (i.e. A/C, coolant fan,
heater motor) while a catalyst test is in progress.
An intermittent problem may be caused by a poor connec-
tion, rubbed–through wire insulation, or a wire that is bro-
ken inside the insulation.
Any circuitry, that is suspected as causing the intermittent
complaint, should be thoroughly checked for the following
conditions:
S Backed–out terminals
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal–to–wire connection.

ENGINE CONTROLS 1F – 231
DAEWOO V–121 BL4
DTC P0420 – Catalyst Low Efficiency
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data link Connector
(DLC).
2. Turn the ignition ON.
Are any component Diagnostic Trouble Codes
(DTCs) set?–Go to
Applicable DTC
tableGo to Step 3
31. Visually/physically check the following:
2. Exhaust system for a leak.
3. Heated Oxygen Sensor (HO2S).
Is a problem found?–Go to Step 4Go to Step 5
4Repair the exhaust system as needed.
Is the repair complete?–Go to Step 6–
5Replace the Three Way Catalytic Converter (TWC).
Is the repair complete?–Go to Step 6–
61. 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 7Go to Step 2
7Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

ENGINE CONTROLS 1F – 345
DAEWOO V–121 BL4
DTCIlluminate MIL Type Description
P0327Knock Sensor Circuit FaultCnlNo
P033658X Crank Position Sensor Extra/Missing PulsesEYe s
P033758X Crank Position Sensor No SignalAYe s
P0341Camshaft Position Sensor RationalityEYe s
P0342Camshaft Position Sensor No SignalAYe s
P0351Ignition Control Circuit A Fault (Cylinder 1 and 4)AYe s
P0352Ignition Control Circuit B Fault (Cylinder 2 and 3)AYe s
P0401Exhaust Gas Recirculation Insufficient FlowCnlNo
P0402Exhaust Gas Recirculation Excessive FlowEYe s
P0404Exhaust Gas Recirculation Open Valve Position ErrorEYe s
P0405Exhaust Gas Recirculation Pintle Position Low VoltageEYe s
P0406Exhaust Gas Recirculation Pintle Position High VoltageEYe s
P0420Catalyst Oxygen Sensor Low EfficiencyAYe s
P0443Evaporative Emission System Purge Solenoid Control CircuitEYe s
P0461Fuel Level StuckCnlNo
P0462Fuel Level Low VoltageCnlNo
P0463Fuel Level High VoltageCnlNo
P0502Vehicle Speed Sensor No Signal (Engine Side)EYe s
P0506Idle Speed rpm Lower Than Desired Idle SpeedEYe s
P0507Idle Speed rpm Higher Than Desired Idle SpeedEYe s
P0532A/C Pressure Sensor Low VoltageCnlNo
P0533A/C Pressure Sensor High VoltageCnlNo
P0562System Voltage Too Low (Engine Side)CnlNo
P0563System Voltage Too High (Engine Side)CnlNo
P0601ECM Checksum Error (Engine Side)AYe s
P0602ECM Reprogram ErrorAYe s
P0607Lower Power Counter ErrorCnlNo
P0700Transaxle Control Module MalfunctionAYe s
P1106Manifold Absolute Pressure Intermittent High VoltageCnlNo
P1107Manifold Absolute Pressure Intermittent Low VoltageCnlNo
P 1111Intake Air Temperature Intermittent High VoltageCnlNo
P1112Intake Air Temperature Intermittent Low VoltageCnlNo
P1114Engine Coolant Temperature Intermittent Low VoltageCnlNo
P1115Engine Coolant Temperature Intermittent High VoltageCnlNo
P1121Throttle Position Sensor Intermittent High VoltageCnlNo
P1122Throttle Position Sensor Intermittent Low VoltageCnlNo
P1133Front Heated Oxygen Sensor (HO2S1) Too Few TransitionsEYe s
P1134Front Heated Oxygen Sensor (HO2S1) Transition RatioEYe s
P1167Front Heated Oxygen Sensor (HO2S1) Rich in Decel Fuel Cut–off (DFCO)AYe s
P1171Fuel Trim System Lean During Power EnrichmentBYe s
P133658X Crank Position Tooth Error Not LearnedAYe s
P1391G Sensor Rough Road RationalityCnlNo

1F – 484IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0420
CATALYST OXYGEN SENSOR 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 cat-
alyst 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
Rear Heated Oxygen Sensor (HO2S2) located in the ex-
haust stream past the TWC. The HO2S2 produces an out-
put signal which indicates the oxygen storage capacity of
the catalyst; 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 id-
ling, and then adding and removing fuel while monitoring
the reaction of the HO2S2. When the catalyst is function-
ing properly, the HO2S2 response to the extra fuel is slow
compared to the Front Heated Oxygen Sensor (HO2S1).
When the HO2S2 response is close to that of the HO2S1,
the Oxygen storage capability or efficiency of the catalyst
is considered to be bad, and the Malfunction Indicator
Lamp (MIL) will illuminate.
Conditions for Setting the DTC
S Oxygen storage capacity index time is less than 0.3
seconds.
S Before idle test, the vehicle needs to be driven for
at least:
S 15 seconds at airflow is greater than 9.2 g/sec.
for manual transaxle.
S 11 seconds at airflow is greater than 12 g/sec
for automatic transaxle.
S Oxygen Sensor Capacity test condition:
S Closed loop stoichiometry.
S Purge concentration learned.
S Engine is running more than 330 seconds.
S Airflow is between 2.5 and 7.25 g/sec.
S Throttle Position (TP) sensor is less than 1.5%.
S Intake Air Temperature (IAT) is between –7°C
(19.4°F) and 105°C (221°F).
S Barometric pressure (BARO) is greater than 72 kPa
(10.4 psi).
S Catalyst temperature is between 500°C (932°F)
and 850°C (1562°F) for automatic transaxle.
S Catalyst temperature is between 450°C (842°F)
and 850°C (1562°F) for automatic transaxle.
S Closed Loop integrator change is less than 0.03.
S Idle time is less than 1 minute.
S Vehicle speed is less than 3 km/h (1.9 mph).S Block Learn Mode is learned.
S Above condition is stabilized for 5 seconds.
Note : Test is aborted for this idle if:
S Change in engine speed is greater than 80 rpm.
S A/C status changed.
S Cooling fan status changed.
S Insufficient air/fuel shift.
S DTC(s) P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0131, P0132, P0133, P1133,
P0134, P0135, P0137, P0138, P0140, P0141,
P1167, P1171, P0171, P0172, P0201, P0202,
P0203, P0204, P0300, P0336, P0337, P0341,
P0342, P0351, P0352, P0402, P0404, P1404,
P0405, P0406, P0443, P0502, P0506, P0507, and
P0562 are not set.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illumi-
nate.
S 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.
S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
The catalyst test may abort due to a change in the engine
load. Do not change the engine load (i.e. A/C, coolant fan,
heater motor) while a catalyst test is in progress.
An intermittent problem may be caused by a poor connec-
tion, rubbed–through wire insulation, or a wire that is bro-
ken inside the insulation.
Any circuitry, that is suspected as causing the intermittent
complaint, should be thoroughly checked for the following
conditions:
S Backed–out terminals
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal–to–wire connection
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.

ENGINE CONTROLS 1F – 485
DAEWOO V–121 BL4
1. The On–Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
2. If any component DTCs are set, diagnose those
DTCs first. A fault in a component can cause the
converter to appear degraded or may have caused
its failure.
3. This step includes checks for conditions that can
cause the three–way catalytic converter to appear
degraded. Repair any problems found before pro-
ceeding with this table.
5. If the three–way catalytic converter needs to be
replaced, make sure that another condition is not
present which would cause the converter to be-
come damaged. These conditions may include thefollowing: misfire, high engine oil or coolant con-
sumption, and/or retarded spark timing or weak
spark. To avoid damaging the replacement convert-
er, correct any possible causes of converter dam-
age before replacing the catalytic converter.
6. Clearing DTCs allows the catalyst test to be run up
to 6 times this ignition cycle. Once the ignition is
cycled, the test will run only once. Driving the ve-
hicle heats the catalyst to a test temperature. The
ECM must see predetermined amount of time at
above idle before allowing the catalyst test to run at
idle. Once at idle, the ECM will allow the system to
stabilize and then test the catalyst in 2 stages.
7. If no faults have been found at this point and no
additional DTCs were set, refer to ”Diagnostic Aids”
in this section for additional checks and informa-
tion.
DTC P0420 – Catalyst Oxygen Sensor Low Efficiency
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
2S Install a scan tool to the Data Link Connector
(DLC).
S Turn the ignition ON.
Are any component Diagnostic Trouble Codes
(DTCs) set?–Go to
applicable DTC
tablesGo to Step 3
3Visually/physically check the following:
S Exhaust system for a leak.
S Rear Heated Oxygen Sensor (HO2S2)
Is a problem found?–Go to Step 4Go to Step 5
4Repair the exhaust system as needed.
Is the repair complete?–Go to Step 6–
5Replace the Three Way Catalytic Converter (TWC).
Is the repair complete?–Go to Step 6–
61. 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 7Go to Step 2
7Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK