2004 DAEWOO LACETTI Fuel tank

ENGINE CONTROLS 1F – 277
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0656
FUEL LEVEL GAUGE CIRCUIT FAULT
Circuit Description
The engine control module(ECM) uses the fuel level input
from the Fuel Level Sensor to calculate expected vapor
pressures within the fuel system. Vapor pressure vary as
the fuel level changes. Vapor pressure is critical in deter-
mining if the evaporative emission (EVAP) system is oper-
ating properly. Fuel Level is also used to determine if the
Fuel level is too high or too low to be able to accurately de-
tect EVAP system faults. This Diagnostic Trouble
Code(DTC) detects a stuck fuel level sender.
Conditions for Setting the DTC
S The fuel tank level output circuit is a short to ground
or a short to battery or an open condition exists.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S The ECM will store conditions which were present
when the DTC was set as Failure Records data
only.
S This information will not be stored in the Freeze
Frame data.Conditions for Clearing the MIL/DTC
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
Inspect harness connectors for backed–out terminal, im-
proper mating, broken locks, improperly formed or dam-
aged terminals, and poor terminal–to–wire connection.
Inspect the wiring harness for damage.
A stuck Fuel Level Sensor may cause the DTC to set. If
DTC P0656 cannot be duplicated, the information in-
cluded in the Freeze Frame data can be useful in deter-
mining vehicle operating conditions when the DTC was
first set.
Resistance check for the Fuel Level Sensor.
S Empty = 100 ohms or over.
S Half full = about 32.5 ohms.
S Full = 10 ohms or less.

ENGINE CONTROLS 1F – 283
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1230
FUEL PUMP RELAY LOW VOLTAGE (1.4L DOHC)
Circuit Description
When the ignition switch is turned ON, the ECM will acti-
vate the fuel pump relay and run the in–tank fuel pump.
The fuel pump will operate as long as the engine is crank-
ing or running and the ECM is receiving ignition reference
pulses.
Conditions for Setting the DTC
S This DTC can be stored in ”key–on” status.
S An open or low voltage condition exists.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S The ECM will store conditions which were present
when the DTC was set as Failure Records data
only.
S This information will not be stored in the Freeze
Frame data.Conditions for Clearing the MIL/DTC
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
An Intermittent problem may be caused by a poor connec-
tion, rubbed through wire insulation, or wire that is broken
inside the insulation.
Any circuitry, that is suspected as causing the 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 terminals to wire connection
S Physical damage to the wiring harness

1F – 284IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1230 – Fuel Pump Relay Low Voltage (1.4L DOHC)
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition switch to LOCK for 10 sec-
onds.
2. Turn the Turn the ignition switch to ON.
3. Listen for in–tank fuel pump operation.
Does the fuel pump operate?2.55 secondsGo to
”Diagnostic
Aids”Go to Step 3
31. Turn the ignition switch to ON.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 85 and ground.
4. Turn the Turn the ignition switch to ON.
Is the test light ON?–Go to Step 4Go to Step 10
41. Turn the ignition switch to ON.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 86 and B+.
4. Turn the Turn the ignition switch to ON.
Is the test light ON?–Go to Step 5Go to Step 9
51. Turn the ignition switch to LOCK.
2. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Is the test light ON?–Go to Step 6Go to Step 8
6Check for short to ground in the wire between the
fuel pump relay connector terminal 87 and fuel pump
connector.
Is the problem found?–Go to Step 7Go to Step 8
71. Repair the wire between the fuel pump relay
connector terminal 87 and fuel pump connector
terminal 3.
2. Install the fuel pump relay.
3. Turn the engine OFF for 10 seconds.
4. Clear any DTCs from ECM.
5. Turn the ignition switch to ON.
Does the fuel pump operate?2.55 secondsGo to Step 14–
81. Replace the fuel pump relay.
2. Turn the ignition OFF for 10 seconds.
3. Clear any DTCs from ECM.
4. Turn the Turn the ignition switch to ON.
Does the fuel pump operate?2.55 secondsGo to Step 14Go to Step 9
9Check for a short to ground wire between the fuel
pump relay connector terminal 86 and the ignition af-
ter key ON(IGN 1).
Is the problem found?–Go to Step 11Go to Step 10
10Check for a short to ground wire between the fuel
pump relay connector terminal 85 and the ECM con-
nector terminal 6.
Is the problem found?–Go to Step 12Go to Step 13

1F – 286IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1230
FUEL PUMP RELAY LOW VOLTAGE (1.6L DOHC)
Circuit Description
When the ignition switch is turned ON, the ECM will acti-
vate the fuel pump relay and run the in–tank fuel pump.
The fuel pump will operate as long as the engine is crank-
ing or running and the ECM is receiving ignition reference
pulses.
Conditions for Setting the DTC
S This DTC can be stored in ”key–on” status.
S An open or low voltage condition exists.
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 Records buffers.
S A history DTC is stored.
S Coolant fan turns ON.
Conditions for Clearing the MIL/DTCS The MIL will turn off after 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 10 sec-
onds.
Diagnostic Aids
An Intermittent problem may be caused by a poor connec-
tion, rubbed through wire insulation, or wire that is broken
inside the insulation.
Any circuitry, that is suspected as causing the 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 terminals to wire connection
S Physical damage to the wiring harness

ENGINE CONTROLS 1F – 287
DAEWOO V–121 BL4
DTC P1230 – Fuel Pump Relay Low Voltage (1.6L DOHC)
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition switch to LOCK for 10 sec-
onds.
2. Turn the Turn the ignition switch to ON.
3. Listen for in–tank fuel pump operation.
Does the fuel pump operate?2.55 secondsGo to
”Diagnostic
Aids”Go to Step 3
31. Turn the ignition switch to ON.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 85 and ground.
4. Turn the Turn the ignition switch to ON.
Is the test light ON?–Go to Step 4Go to Step 10
41. Turn the ignition switch to ON.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 86 and B+.
4. Turn the Turn the ignition switch to ON.
Is the test light ON?–Go to Step 5Go to Step 9
51. Turn the ignition switch to LOCK.
2. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Is the test light ON?–Go to Step 6Go to Step 8
6Check for short to ground in the wire between the
fuel pump relay connector terminal 87 and fuel pump
connector.
Is the problem found?–Go to Step 7Go to Step 8
71. Repair the wire between the fuel pump relay
connector terminal 87 and fuel pump connector
terminal 3.
2. Install the fuel pump relay.
3. Turn the engine OFF for 10 seconds.
4. Clear any DTCs from ECM.
5. Turn the ignition switch to ON.
Does the fuel pump operate?2.55 secondsGo to Step 14–
81. Replace the fuel pump relay.
2. Turn the ignition OFF for 10 seconds.
3. Clear any DTCs from ECM.
4. Turn the Turn the ignition switch to ON.
Does the fuel pump operate?2.55 secondsGo to Step 14Go to Step 9
9Check for a short to ground wire between the fuel
pump relay connector terminal 86 and the ignition af-
ter key ON(IGN 1).
Is the problem found?–Go to Step 11Go to Step 10
10Check for a short to ground wire between the fuel
pump relay connector terminal 85 and the ECM con-
nector terminal 6.
Is the problem found?–Go to Step 12Go to Step 13

ENGINE CONTROLS 1F – 289
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1231
FUEL PUMP RELAY HIGH VOLTAGE (1.4L DOHC)
Circuit Description
When the ignition switch is turned ON, the ECM will acti-
vate the fuel pump relay and run the in–tank fuel pump.
The fuel pump will operate as long as the engine is crank-
ing or running and the ECM is receiving ignition reference
pulses.
Conditions for Setting the DTC
S This DTC can be stored in ”key–on” status.
S A high voltage condition exists.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S The ECM will store conditions which were present
when the DTC was set as Failure Records data
only.
S This information will not be stored in the Freeze
Frame data.Conditions for Clearing the MIL/DTC
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
An Intermittent problem may be caused by a poor connec-
tion, rubbed through wire insulation, or wire that is broken
inside the insulation.
Any circuitry, that is suspected as causing the 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 terminals to wire connection
S Physical damage to the wiring harness

1F – 290IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1231 – Fuel Pump Relay High Voltage (1.4L DOHC)
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition switch to LOCK for 10 sec-
onds.
2. Turn the Turn the ignition switch to ON.
3. Listen for in–tank fuel pump operation.
Does the fuel pump operate?2.55 secondsGo to
”Diagnostic
Aids”Go to Step 3
3Check for short to battery voltage or low voltage in
the wire between the fuel pump relay connector ter-
minal 87 and fuel pump connector 3.
Is the problem found?–Go to Step 7Go to Step 5
41. Repair the wire between the fuel pump relay
connector terminal 87 and fuel pump connector
terminal 3.
2. Install the fuel pump relay.
3. Turn the engine OFF for 10 seconds.
4. Clear any DTCs from ECM.
5. Turn the ignition switch to ON.
Does the fuel pump operate?2.55 secondsGo to Step 11–
51. Replace the fuel pump relay.
2. Turn the ignition OFF for 10 seconds.
3. Clear any DTCs from ECM.
4. Turn the Turn the ignition switch to ON.
Does the fuel pump operate?2.55 secondsGo to Step 11Go to Step 6
6Check for short to battery voltage wire between the
fuel pump relay connector terminal 86 and the igni-
tion after key ON(IGN 1).
Is the problem found?–Go to Step 8Go to Step 7
7Check for an open wire between the fuel pump relay
connector terminal 85 and the ECM connector termi-
nal 6.
Is the problem found?–Go to Step 9Go to Step 10
81. Repair the wire between the fuel pump relay
connector terminal 86 and the ignition key ON
(IGN1).
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Clear any DTCs from ECM.
5. Turn the ignition switch to ON.
Does the fuel pump operate?2.55 secondsSystem OKGo to Step 10
91. Repair the wire between the fuel pump relay
connector terminal 85 and the ECM connector
terminal 6.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Clear any DTCs from ECM.
5. Turn the ignition switch to ON.
Does the fuel pump operate?2.55 secondsSystem OKGo to Step 10

1F – 292IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1231
FUEL PUMP RELAY HIGH VOLTAGE (1.6L DOHC)
Circuit Description
When the ignition switch is turned ON, the ECM will acti-
vate the fuel pump relay and run the in–tank fuel pump.
The fuel pump will operate as long as the engine is crank-
ing or running and the ECM is receiving ignition reference
pulses.
Conditions for Setting the DTC
S This DTC can be stored in ”key–on” status.
S A high voltage condition exists.
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 Records buffers.
S A history DTC is stored.
S Coolant fan turns ON.
Conditions for Clearing the MIL/DTCS The MIL will turn off after 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 10 sec-
onds.
Diagnostic Aids
An Intermittent problem may be caused by a poor connec-
tion, rubbed through wire insulation, or wire that is broken
inside the insulation.
Any circuitry, that is suspected as causing the 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 terminals to wire connection
S Physical damage to the wiring harness