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–114 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F040
DIAGNOSTIC TROUBLE CODE (DTC) – P1230 FUEL PUMP RELAY LOW
V O LTA G E
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
cranking or running and the ECM is receiving ignition
reference pulses.
Conditions for Setting the DTC
This DTC can be stored in “key-on” status.
An open or low voltage condition exists.
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 Records buffers.
A history DTC is stored.
Coolant fan turns ON.
Conditions for Clearing the MIL/DTC
The MIL will turn off after 4 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
An Intermittent problem may be caused by a poor con-
nection, rubbed through wire insulation, or wire that is
broken inside the insulation.
Any circuitry, that is suspected as causing the com-
plaint, should be thoroughly checked for the following
conditions.
Backed-out terminals
Improper mating
Broken locks
Improperly formed
Damaged terminals
Poor terminals to wire connection
Physical damage to the wiring harness
ENGINE CONTROLS 1F–11 5
DAEWOO M-150 BL2
DTC P1230 – Fuel Pump Relay Low Voltage
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
1. Turn the ignition switch to LOCK for 10 seconds.
2. Turn the Turn the ignition switch to ON.
3. Listen for in-tank fuel pump operation.
Does the fuel pump operate?
2.55 seconds
Go to
“Diagnostic
Aids”
Go to Step 3
3
1. Turn the 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
4
1. Turn the Turn the ignition switch to ON.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump relay
connector terminal 66 and B+.
4. Turn the Turn the ignition switch to ON.
Is the test light ON?
–
Go to Step 5Go to Step 9
5
1. 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
6
Check 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
7
1. 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
–
8
1. 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
9
Check for a short to ground wire between the fuel
pump relay connector terminal 66 and the ignition
after key ON 1(IGN 1).
Is the problem found?
–
Go to Step 11Go to Step 10
10
Check for a short to ground wire between the fuel
pump relay connector terminal 85 and the ECM
connector terminal 10.
Is the problem found?
–
Go to Step 12Go to Step 13
1F–116 ENGINE CONTROLS
DAEWOO M-150 BL2
DTC P1230 – Fuel Pump Relay Low Voltage (Cont’d)
StepActionValue(s)YesNo
11
1. Repair the wire between the fuel pump relay
connector terminal 66 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 13
12
1. Repair the wire between the fuel pump relay
connector terminal 85 and the ECM connector
terminal 10.
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 13
13
1. Replace the ECM.
2. Turn the ignition OFF for 10 seconds.
3. Clear any DTCs from ECM.
4. Turn the ignition switch to ON.
Does the fuel pump operate?
2.55 secondsSystem OKGo to Step 14
14
1. Using the scan tool, clear the DTCs.
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the conditions for
setting this DTC ad specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?
–
Go to Step 15Go to Step 2
15
Check if any additional DTCs are set.
Are any DTCs displayed that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK
1F–118 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F040
DIAGNOSTIC TROUBLE CODE (DTC) – P1231 FUEL PUMP RELAY HIGH
V O LTA G E
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
cranking or running and the ECM is receiving ignition
reference pulses.
Conditions for Setting the DTC
This DTC can be stored in “key-on” status.
A high voltage condition exists.
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 Records buffers.
A history DTC is stored.
Coolant fan turns ON.
Conditions for Clearing the MIL/DTC
The MIL will turn off after 4 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 10 seconds.
Diagnostic Aids
An Intermittent problem may be caused by a poor con-
nection, rubbed through wire insulation, or wire that is
broken inside the insulation.
Any circuitry, that is suspected as causing the com-
plaint, should be thoroughly checked for the following
conditions.
Backed-out terminals
Improper mating
Broken locks
Improperly formed
Damaged terminals
Poor terminals to wire connection
Physical damage to the wiring harness
ENGINE CONTROLS 1F–11 9
DAEWOO M-150 BL2
DTC P1231 – Fuel Pump Relay High Voltage
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
1. Turn the ignition switch to LOCK for 10 seconds.
2. Turn the Turn the ignition switch to ON.
3. Listen for in-tank fuel pump operation.
Does the fuel pump operate?
2.55 seconds
Go to
“Diagnostic
Aids”
Go to Step 3
3
Check for short to battery voltage or low voltage in
the wire between the fuel pump relay connector
terminal 87 and fuel pump connector 3.
Is the problem found?
–
Go to Step 7Go to Step 5
4
1. 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
–
5
1. 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
6
Check for short to battery voltage wire between the
fuel pump relay connector terminal 66 and the
ignition after key ON 1(IGN 1).
Is the problem found?
–
Go to Step 8Go to Step 7
7
Check for an open wire between the fuel pump relay
connector terminal 85 and the ECM connector
terminal 10.
Is the problem found?
–
Go to Step 9Go to Step 10
8
1. Repair the wire between the fuel pump relay
connector terminal 66 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 13
9
1. Repair the wire between the fuel pump relay
connector terminal 85 and the ECM connector
terminal 10.
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–120 ENGINE CONTROLS
DAEWOO M-150 BL2
DTC P1231 – Fuel Pump Relay High Voltage (Cont’d)
StepActionValue(s)YesNo
10
1. Replace the ECM.
2. Turn the ignition OFF for 10 seconds.
3. Clear any DTCs from ECM.
4. Turn the ignition switch to ON.
Does the fuel pump operate?
2.55 secondsSystem OKGo to Step 11
11
1. Using the scan tool, clear the DTCs.
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the conditions for
setting this DTC ad specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?
–
Go to Step 12Go to Step 2
12
Check if any additional DTCs are set.
Are any DTCs displayed that have not been
diagnosed?
–
Go to
applicable DTC
table
System OK
1F–122 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F150
DIAGNOSTIC TROUBLE CODE (DTC) – P0261 INJECTOR 1 LOW VOLTAGE
Circuit Description
The engine control module (ECM) has three individual
injector driver circuits, each of which controls an injector.
When a driver circuit is grounded by the ECM, the injec-
tor is activated. The ECM monitors the current in each
driver circuit. The ECM measures a voltage drop
through a fixed resistor and controls it. The voltage on
each driver is monitored to detect a fault. If the voltage is
not what the ECM expects to monitor on the circuit, a
Diagnostic Trouble Code (DTC) is set. This DTC detects
a low voltage and/or an open circuit and high voltage
conditions for low-side drive injector outputs.
Conditions for Setting the DTC
This DTC can be stored in “key-on” status.
The injector voltage does not equal the ignition volt-
age when the injector is commanded OFF, or the in-
jector voltage does not equal 0 volts when the injector
is commanded ON.
The battery voltage is less than 9 volts.
The above conditions are met for 5seconds.
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 Records buffers.
A history DTC is stored.
Conditions for Clearing the MIL/DTC
The MIL will turn off after 4 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
An injector 4river circuit that is open or shorted to volt-
age will causes a DTC P0261 to set. It will also cause a
misfire due to an inoperative injector. A misfire DTC
should also be set indicating which injector is inopera-
tive.
Long-term and short-terms fuel trims that are excessive-
ly high or low are a good indication that an injector is
malfunctioning. Refer to “Fuel Injector 2alance Test” in
this Section to check for malfunctioning injectors.
The injector resistance tested at the ECM connection is
slightly more than it tested directly at the injector
2ecause it includes resistance of the harness wires. The
normal value is about 13.5Ω.