Daewoo Nubira. Manual - part 111

1F – 26

I

ENGINE CONTROLS

DAEWOO V–121 BL4

COMPONENT LOCATOR

ENGINE CONTROLS  1F – 27

DAEWOO V–121 BL4

Components on PCM/ECM Harness

11. Powertrain Control Module (PCM)/Engine Control

Module (ECM)

12. Data Link Connector (DLC)
13. Service Reminder Indicator Lamp/Malfunction Indi-

cator Lamp

14. PCM/ECM/ABS Harness Ground
15. Fuse Panel (2)

PCM/ECM Controlled Devices

19. Exhaust Gas Recirculation (EGR) Valve
21. Fuel Injector (4)
22. Idle Air Control (IAC) Valve
23. Fuel Pump Relay
24. Cooling Fan Relays
25. Series/Parallel Cooling Fan Relay (A/C Only)
26. Electronic Ignition (EI) System Ignition Coil
27. Evaporative Emission (EVAP) Controlled Canister

Purge Solenoid

28. Ignition 1 Relay
29. A/C Compressor Relay

30. Variable Geometry Induction System (VGIS)

Information Sensors

31. Manifold Absolute Pressure (MAP) Sensor
32. Pre–Converter Oxygen Sensor (O2S 1)
33. Throttle Position (TP) Sensor
34. Engine Coolant Temperature (ECT) Sensor
35. Intake Air Temperature (IAT) Sensor
36. Vehicle Speed Sensor (VSS)
37. P/N Position Switch (Automatic Transaxle only)
38. Crankshaft Position (CKP) Sensor
39. Knock Sensor
40. Post–Converter Oxygen (HO2S 2) Sensor
41. Camshaft Position (CMP) Sensor

PCM/Not ECM Connected

42. Evaporative Emission Canister (under vehicle, be-

hind right rear wheel)

43. Oil Pressure Switch
44. Air Cleaner

1F – 28

I

ENGINE CONTROLS

DAEWOO V–121 BL4

DIAGNOSIS

SYSTEM DIAGNOSIS

DIAGNOSTIC AIDS

If an intermittent problem is evident, follow the guidelines
below.

Preliminary Checks

Before using this section you should have already per-
formed the ”On–Board Diagnostic System Check.”

Perform a thorough visual inspection. This inspection can
often lead to correcting a problem without further checks
and can save valuable time. Inspect for the following con-
ditions:

S

 

Powertrain control module (PCM)/engine control
module (PCM/ECM) grounds for being clean, tight,
and in their proper location.

S

 

Vacuum hoses for splits, kinks, collapsing and prop-
er connections as shown on the Vehicle Emission
Control Information label. Inspect thoroughly for
any type of leak or restriction.

S

 

Air leaks at the throttle body mounting area and the
intake manifold sealing surfaces.

S

 

Ignition wires for cracks, hardness, proper routing,
and carbon tracking.

S

 

Wiring for proper connections.

S

 

Wiring for pinches or cuts.

Diagnostic Trouble Code Tables

Do not use the diagnostic trouble code (DTC) tables to try
to correct an intermittent fault. The fault must be present
to locate the problem.

Incorrect use of the DTC tables may result in the unneces-
sary replacement of parts.

Faulty Electrical Connections or Wiring

Most intermittent problems are caused by faulty electrical
connections or wiring. Perform a careful inspection of sus-
pect circuits for the following:

S

 

Poor mating of the connector halves.

S

 

Terminals not fully seated in the connector body.

S

 

Improperly formed or damaged terminals. All con-
nector terminals in a problem circuit should be care-
fully inspected, reformed, or replaced to insure con-
tact tension.

S

 

Poor terminal–to–wire connection. This requires
removing the terminal from the connector body.

Road Test

If a visual inspection does not find the cause of the prob-
lem, the vehicle can be driven with a voltmeter or a scan
tool connected to a suspected circuit. An abnormal voltage
or scan tool reading will indicate that the problem is in that
circuit.

If there are no wiring or connector problems found and a
DTC was stored for a circuit having a sensor, except for
DTC P0171 and DTC P0172, replace the sensor.

Intermittent Service Reminder Indicator (SRI) Lamp

An intermittent service reminder indicator (SRI) lamp with
no DTC present may be caused by the following:

S

 

Electrical system interference caused by a defec-
tive relay, PCM/ECM driven solenoid, or switch.

S

 

Improper installation of electrical options such as
lights, two–way radios, sound systems, or security
systems.

S

 

Ignition control wires should be routed away from
ignition wires, ignition system components, and the
generator.

S

 

Ignition secondary wires shorted to ground.

S

 

SRI lamp driver wire or diagnostic test terminal in-
termittently shorted to ground.

S

 

Intermittent lose of PCM/ECM ground connections.

Fuel System

Some intermittent driveability problems can be attributed
to poor fuel quality. If a vehicle is occasionally running
rough, stalling, or otherwise performing badly, ask the cus-
tomer about the following fuel buying habits:

S

 

Do they always buy from the same source? If so,
fuel quality problems can usually be discounted.

S

 

Do they buy their fuel from whichever fuel station
that is advertising the lowest price? If so, check the
fuel tank forsigns of debris, water, orotherconta-
mination.

IDLE LEARN PROCEDURE

Whenever the battery cables, the powetrain control mod-
ule (PCM)/engine control module (PCM/ECM), or the
PCM/ECM fuse is disconnected or replaced, the following
idle learn procedure must be performed:

1.  Turn the ignition ON for 5 seconds.
2.  Turn the ignition OFF for 5 seconds.
3.  Turn the ignition ON for 5 seconds.
4.  Start the engine in park/neutral.
5.  Allow the engine run until the engine coolant is

above 85

°

C (185

°

F).

6.  Turn the A/C ON for 10 seconds, if equipped.
7.  Turn the A/C OFF for 10 seconds, if equipped.
8.  If the vehicle is equipped with an automatic trans-

axle, apply the parking brake. While pressing the
brake pedal, place the transaxle in D (drive).

9.  Turn the A/C ON for 10 seconds, if equipped.
10.  Turn the A/C OFF for 10 seconds, if equipped.
11.  Turn the ignition OFF. The idle learn procedure is

complete.

ENGINE CONTROLS  1F – 29

DAEWOO V–121 BL4

ON–BOARD DIAGNOSTIC (OBD II) SYSTEM CHECK

Circuit Description

The On–Board Diagnostic (OBD II) System Check is the
starting point for any driveability complaint diagnosis. Be-
fore using this procedure, perform a careful visual/physi-
cal check of the powertrain control module (PCM)/engine
control module (ECM) and the engine grounds for cleanli-
ness and tightness.

The OBD II System Check is an organized approach to
identifying a problem created by an electronic engine con-
trol system malfunction.

Diagnostic Aids

An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside the
insulation. Check for poor connections or a damaged har-
ness. Inspect the PCM/ECM harness and connections for
improper mating, broken locks, improperly formed or dam-
aged terminals, poor terminal–to–wire connection, and
damaged harness.

Test Description

Numbers below refer to the step number on the Diagnostic
Chart:

1.

The Malfunction Indicator Lamp (MIL) should be
ON steady with the ignition ON and the engine
OFF. If not, go to ”Diagnostic Aids”.

2.

Checks the Class 2 data circuit and ensures that
the PCM/ECM is able to transmit serial data.

3.

This test ensures that the PCM/ECM is capable of
controlling the MIL and the MIL driver circuit is not
shorted to ground.

4.

If the engine will not start, refer to ”Engine Cranks
But Will Not Run” in this section.

7.

A scan tool parameter which is not within the typical
range may help to isolate the area which is causing
the problem.

10. This vehicle is equipped with a PCM/ECM which

utilizes an electrically erasable programmable read
only memory (EEPROM). The replacement PCM/
ECM must be programmed. Refer to the latest
Techline procedure for PCM/ECM reprogramming.