Page 209 of 1184

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
–
Page 210 of 1184
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
Page 211 of 1184
ENGINE CONTROLS 1F–11 3
DAEWOO M-150 BL2
BLANK
Page 212 of 1184

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
Page 213 of 1184

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
Page 214 of 1184

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
Page 215 of 1184
ENGINE CONTROLS 1F–11 7
DAEWOO M-150 BL2
BLANK
Page 216 of 1184

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