ENGINE CONTROLS 1F – 29
DAEWOO V–121 BL4
COMPONENT LOCATOR (1.8L DOHC)
Components on ECM Harness
11. Engine Control Module (ECM)
12. Data Link Connector (DLC)
13. Malfunction Indicator Lamp (MIL)
14. ECM/ABS Harness Ground
15. Fuse Panel (2)
ECM Controlled Devices
20. Exhaust Gas Recirculation (EGR) Valve
21. Fuel Injector (4)
22. Idle Air Control (IAC) Valve
23. Fuel Pump Relay
24. Cooling Fan Relays (High)
25. Cooling Fan Control Relay (A/C Only)
26. Electronic Ignition System Ignition Coil
27. Evaporative Emission (EVAP) Control Purge Sole-
noid
28. Main Relay
29. A/C Compressor Relay30. Cooling Fan Relays (Low)
Information Sensors
31. Manifold Absolute Pressure (MAP) Sensor
32. Front Heated Oxygen Sensor (HO2S1)
33. Throttle Position (TP) Sensor
34. Engine Coolant Temperature (ECT) Sensor
35. Intake Air Temperature (IAT) Sensor
36. Vehicle Speed Sensor (VSS)
38. Crankshaft Position (CKP) Sensor
39. Knock Sensor
40. Rear Heated Oxygen Sensor (HO2S2)
41. Camshaft Position (CMP) Sensor
Not PCM/ECM Connected
42. Evaporative Emission Canister (under vehicle, be-
hind right rear wheel)
43. Engine Oil Pressure Switch
44. Air Cleaner
ENGINE CONTROLS 1F – 43
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
301. Disconnect vacuum line from the fuel pressure
regulator.
2. Inspect the vacuum line for the presence of
fuel.
3. Inspect the fuel pressure regulator vacuum port
for the presence of fuel.
Is any fuel present?–Go to Step 31Go to Step 32
31Replace the fuel pressure regulator.
Is the repair complete?–Go to Step 2–
321. Remove the fuel pump assembly from the fuel
tank.
2. Inspect the fuel pump sender and the fuel cou-
pling hoses for a restriction.
3. Inspect the in–tank fuel filter for restriction.
Is the problem found?–Go to Step 33Go to Step 25
33Replace the fuel pump sender, the in–tank fuel filter,
and/or the fuel coupling hoses as needed.
Is the repair complete?–Go to Step 2–
341. Turn the ignition OFF.
2. Disconnect the electric connector at the fuel
pump.
3. Connect a test light between fuel pump con-
nector terminal 3 and ground.
4. Turn the ignition ON.
5. With the ignition ON, the test light should illumi-
nate for the time specified.
Is the test light on?2 secGo to Step 35Go to Step 36
35Repair the open circuit between the fuel pump con-
nector terminal 2 and ground.
Is the repair complete?–Go to Step 2–
361. Turn the ignition OFF.
2. Disconnect the fuel pump relay.
3. Turn the ignition ON.
4. Measure the voltage at terminal 30 and 86 of
fuel pump relay.
Is the voltage within the value specified?11–14 VGo to Step 38Go to Step 37
37Repair open or short circuit for power supply.
Is the repair complete?–Go to Step 2–
381. Turn the ignition OFF.
2. Disconnect ECM connector.
3. Using an ohmmeter, measure the resistance
between following terminals.
S Terminal 6 of ECM and terminal 85 of fuel
pump relay.
S Terminal 87 of fuel pump relay and terminal
3 of fuel pump.
Does the resistance within the value specified?0 WGo to Step 40Go to Step 39
1F – 44IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
39Repair the open or short circuit the following termi-
nals.
S Terminal 6 of ECM and terminal 86 of fuel
pump relay.
S Terminal 87 of fuel pump relay and terminal
3 of fuel pump.
Is the repair complete?–Go to Step 2–
40Replace the fuel pump relay.
Is the repair complete?–Go to Step 2–
411. Turn the ignition OFF.
2. Disconnect the fuel inject harness connectors
from all of the fuel injectors.
3. Turn the ignition ON.
4. Connect test light between fuel injector harness
connector 2 and ground.
5. Repeat step 4 for each of the remaining fuel
injectors.
Does the test light on at all of the fuel injectors?–Go to Step 42Go to Step 45
421. Turn the ignition OFF.
2. Connect test light between fuel injector harness
connector 1 and battery positive.
3. Crank the engine.
4. Repeat step 2 and 3 for each of the remaining
fuel injectors.
Does the test light flash for all of the fuel injectors?–Go to Step 43Go to Step 46
43Measure the resistance of each fuel injectors.
Is the resistance within the value specified.
Notice : the resistance will increase slightly at higher
temperature.11.6–12.4WSystem OKGo to Step 44
44Replace any of the fuel injectors with a resistance
out of specification.
Is the repair complete?–Go to Step 2–
451. Inspect the fuse EF22 in engine fuse block.
2. Check for an open between the circuit from
terminal 2 of the four fuel injectors and terminal
87 of main relay.
Is the problem found?–Go to Step 48Go to
”Main Relay
Circuit Check”
46Measure the resistance between following termi-
nals.
S Terminal 2 of injector 1 connector and terminal
59 of ECM connector.
S Terminal 2 of injector 2 connector and terminal
90 of ECM connector.
S Terminal 2 of injector 3 connector and terminal
60 of ECM connector.
S Terminal 2 of injector 4 connector and terminal
89 of ECM connector.
Does the resistance within the specified value?0 WGo to Step 49Go to Step 47
47Repair the open fuel injector harness wire(s).
Is the repair complete?–Go to Step 2–
ENGINE CONTROLS 1F – 51
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
471. Disconnect the vacuum line from the fuel pres-
sure regulator.
2. Inspect the vacuum line for the presence of
fuel.
3. Inspect the fuel pressure regulator vacuum port
for the presence of fuel.
Is any fuel presen–Go to Step 50Go to Step 51
48Check the fuel for contamination.
Is the fuel contaminated?–Go to Step 49Go to Step 65
491. Remove the contaminated fuel from the fuel
tank.
2. Clean the fuel tank as needed.
Is the repair complete?–Go to Step 3–
50Replace the fuel pressure regulator.
Is the repair complete?–Go to Step 3–
511. Remove the fuel pump assembly from the fuel
tank.
2. Inspect the fuel pump sender and the fuel cou-
pling hoses for a restriction.
3. Inspect the in–tank fuel filter for a restriction.
Is the problem found?–Go to Step 52Go to Step 43
52Replace the fuel pump sender, the in–tank fuel filter,
and/or the fuel coupling hoses as needed.
Is the repair complete?–Go to Step 3–
531. Turn the ignition OFF.
2. Disconnect the electrical connector at the fuel
pump.
3. Connect a test light between the fuel pump
connector terminal 3 and a known good
ground.
4. Turn the ignition ON.
5. With the ignition ON, the test light should light
for the time specified.
Is the test light on?2 secGo to Step 54Go to Step 55
54Repair the open wire between the fuel pump connec-
tor terminal 2 and ground.
Is the repair complete–Go to Step 3–
551. Turn the ignition OFF.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 85 and ground.
4. Turn the ignition ON.
Is the test light on?2 secGo to Step 56Go to Step 62
561. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 86 and battery posi-
tive.
3. Turn the ignition ON.
4. With the ignition ON, the test light should light
for the time specified.
Is the test light on?–Go to Step 57Go to Step 61
1F – 52IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
571. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Is the test light on?–Go to Step 58Go toStep 63
581. Turn the ignition OFF.
2. Check the wire between the fuel pump relay
connector terminal 87 and the fuel pump con-
nector terminal 3 for an open or short to
ground.
Is the repair complete?–Go to Step 2–
59Replace the fuel pump relay.
Is the repair complete?–Go to Step 3–
601. Check for an open in the wiring between the
fuel pump relay connector terminal 86 and
ground.
Is the problem found?–Go to Step 71–
61Check the wire between the fuel pump relay connec-
tor terminal 85 to the ECM connector terminal K54
for an open.
Is the problem found?–Go to Step 62Go to Step 40
62Repair the wire between the fuel pump relay connec-
tor terminal 85 to the ECM connector terminal K54.
Is the repair complete?–Go to Step 3–
63Repair the wire between the fuel pump relay connec-
tor terminal 30 and the fuse Ef18.
Is the repair complete?–Go to Step 3–
641. Turn the ignition OFF.
2. Disconnect the fuel injector harness connectors
from all of the fuel injectors.
3. Turn the ignition ON.
4. Connect a test light between the fuel injector
harness connector 2 and ground.
5. Repeat step 4 for each of the remaining fuel
injectors.
Is the test light on at all of the fuel injectors?–Go to Step 65Go to Step 68
651. Turn the ignition OFF.
2. Connect a test light between the fuel injector
harness connector terminal 1 and battery posi-
tive.
3. Crank the engine.
4. Repeat steps two and three for each of the re-
maining fuel injectors.
Does the test light flash for all of the fuel injectors?–Go to Step 66Go to Step 69
66Measure the resistance of each fuel injector.
Is the resistance within the value specified (the re-
sistance will increase slightly at higher tempera-
tures)?11.6–12.4 WSystem OKGo to Step 67
67Replace any of the fuel injectors with a resistance
out of specification.
Is the repair complete?–Go to Step 3–
ENGINE CONTROLS 1F – 65
DAEWOO V–121 BL4
FUEL PUMP RELAY CIRCUIT CHECK (1.4L/1.6L DOHC)
Circuit Description
When the ignition switch is turned ON, the Engine Control
Module (ECM) will supply battery voltage to activate the
fuel pump relay and run the in–tank fuel pump. The fuel
pump will operate as long as the engine is cranking or run-
ning and the ECM is receiving ignition reference pulses.
If there are no reference pulses, the ECM will shut off the
fuel pump within 2 seconds after the ignition switch is
turned ON.
Diagnostic Aids
An intermittent problem may be caused by a poor connec-
tion, rubbed through wire insulation, or a broken wire in-
side the insulation.Test Description
The number(s) below refer to step(s) on the diagnostic
table.
3. This step checks for the ECM providing a ground
for the operation of the fuel pump relay.
7. By confirming that the wiring is OK using Steps 2
through 6, it can be determined that the fuel pump
relay is at fault.
9. After determining that there is no ground being pro-
vided by the ECM to the fuel pump relay, the fault is
either the ECM or the wiring between the ECM and
the fuel pump relay.
1F – 66IENGINE CONTROLS
DAEWOO V–121 BL4
Fuel Pump Relay Circuit Check (1.4L/1.6L DOHC)
StepActionValue(s)YesNo
11. Turn the ignition OFF for 10 seconds.
2. Turn the ignition ON.
3. Listen for in–tank fuel pump operation.
Does the fuel pump operate for the time specified?2 secSystem OKGo to Step 2
21. Turn the ignition OFF.
2. Disconnect the fuel pump relay.
3. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Turn the ignition ON. Is the test light on?–Go to Step 3Go to Step 8
31. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 86 and battery posi-
tive.
3. Turn the ignition ON.
4. With the ignition ON, the test light should light
for the time specified.
Is the test light on?2 secGo to Step 4Go to Step 9
41. Turn the ignition OFF.
2. Connect a test light between the fuel pump
relay connector terminal 30 and ground.
Is the test light on?–Go to Step 5Go to Step 11
5Check for an open or short to ground in the wire be-
tween the fuel pump relay connector terminal 87 and
the fuel pump connector terminal 3.
Is the problem found?–Go to Step 6Go to Step 7
61. Repair the wire between the fuel pump relay
connector terminal 87 and the fuel pump con-
nector terminal 3.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
71. Replace the fuel pump relay.
2. Turn the ignition OFF for 10 seconds.
3. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
8Check for an open wire between the fuel pump relay
connector terminal 30 and the battery.
Is the problem found?–Go to Step 13–
9Check for an open wire between the fuel pump relay
connector terminal 86 to the engine control module
(ECM) connector terminal 6.
Is the problem found.–Go to Step 10Go to Step 12
101. Repair the wire between the fuel pump relay
connector terminal 86 to the ECM connector
terminal 6.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
ENGINE CONTROLS 1F – 67
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
111. Replace the fuse F2 or repair the wire between
the fuel pump relay connector terminal 30 and
the battery.
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
121. Turn the ignition OFF.
2. Replace the ECM.
3. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–
131. Replace the fuse F2 or repair the wire between
the fuel pump relay connector terminal 30 and
the ignition system
2. Install the fuel pump relay.
3. Turn the ignition OFF for 10 seconds.
4. Turn the ignition ON.
Does the fuel pump operate for the time specified?2 secSystem OK–