Daewoo Matiz (2003 year). Manual - part 27

1F – 18  ENGINE CONTROLS

MAA1F010

EURO ON-BOARD DIAGNOSTIC (EOBD) SYSTEM CHECK

Circuit Description

The Euro On-Board Diagnostic (EOBD) System Check
is the starting point for any driveability complaint diagno-
sis. Before using this procedure, perform a careful visu-
al/physical check of the Engine Control Module (ECM)
and the engine grounds for cleanliness and tightness.

The EOBD system check is an organized approach to
identifying a problem created by an electronic engine
control 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 dam-
aged harness. Inspect the ECM harness and connec-
tions for improper mating, broken locks, improperly
formed or damaged terminals, poor terminal-to-wire
connections, and damaged harness.

ENGINE CONTROLS  1F – 19

Euro On-Board Diagnostic (EOBD) System Check

Step

Action

Value(s)

Yes

No

1

1. Turn the ignition ON with the engine OFF.
2. Observe the Malfunction Indicator Lamp (MIL).
Is the MIL on?

–

Go to Step 2

Go to “No

Malfunction

Indicator

Lamp”

2

1. Turn the ignition OFF.
2. Install the scan tool.
3. Turn the ignition ON.
4. Attempt to display the Engine Control Module

(ECM) engine data with the scan tool.

Does the scan tool display the ECM engine data?

–

Go to Step 3

Go to Step 8

3

1. Using the scan tool output test function, select the

MIL lamp control and command the MIL off.

2. Observe the MIL.
Does the MIL turn off?

–

Go to Step 4

Go to

“Malfunction

Indicator Lamp

on Steady”

4

Attempt to start the engine.
Does the engine start and continue to run?

–

Go to Step 5

Go to “Engine

Cranks But

Will Not Run”

5

Select DISPLAY DTC with the scan tool.
Are any Diagnostic Trouble Codes stored?

–

Go to Step 6

Go to Step 7

6

Check the display for DTCs P0107, P0108, P0113,
P0118, P0122, P0123, P0172, P1392.
Are two or more of the following DTCs stored?

–

Go to “Multiple

ECM

Information

Sensor DTCs

Set”

Go to

applicable DTC

table

7

Compare the ECM data values displayed on the
scan tool to the typical engine scan data values.
Are the displayed values normal or close to the
typical values?

–

Go to “ECM

Output

Diagnosis”

Go to indicated

component

system check

8

1. Turn the ignition OFF and disconnect the ECM.
2. Turn the ignition ON with the engine OFF.
3. Check the serial data circuit for an open, short to

ground, or short to voltage. Also check the Data
Link Connector (DLC) ignition feed circuit for an
open or short to ground, and check the DLC
ground circuits for an open.

Is a problem found?

–

Go to Step 9

Go to Step 10

9

Repair the open, short to ground, or short to voltage
in the serial data circuit or the DLC ignition feed
circuit.
Is the repair complete?

–

System OK

–

10

1. Attempt to reprogram the ECM.
2. Attempt to display the ECM data with the scan

tool.

Does the scan tool display ECM engine data?

–

Go to Step 2

Go to Step 11

11

Replace the ECM.
Is the repair complete?

–

System OK

–

1F – 20  ENGINE CONTROLS

ECM OUTPUT DIAGNOSIS

Circuit Description

The Engine Control Module (ECM) controls most com-
ponents with electronic switches which complete a
ground circuit when turned on. These switches are ar-
ranged in groups of 4 and 7, and they are called either a
Surface Mounted Quad Driver Module, which can inde-
pendently control up to 4 output terminals or an Output
Driver Module (ODM), which can independently control
up to 7 outputs. Not all of the outputs are always used.

Drivers are fault protected. If a relay or solenoid is
shorted, having very low or zero resistance, or if the con-
trol side of the circuit is shorted to voltage, it would allow
too much current flow into the ECM. The driver senses
this and the output is either turned OFF or its internal re-
sistance increases to limit current flow and protect the
ECM and driver. The result is high output terminal volt-
age when it should be low. If the circuit from B+ to the
component or the component is open, or the control side
of the circuit is shorted to ground, terminal voltage will

be low. Either of these conditions is considered to be a
driver fault.

Drivers also have a fault line to indicate the presence of
a current fault to the ECM’s central processor. A scan
tool displays the status of the driver fault lines as 0=OK
and 1=Fault.

Diagnostic Aids

The scan tool has the ability to command certain compo-
nents and functions ON and OFF. If a component or
function does not have this capability, operate the ve-
hicle during its normal function criteria to check for an
open or shorted circuit.

An open or short to ground will appear in the open posi-
tions on the scan tool only when it is not commanded by
the ECM or the scan tool, while a short to voltage will
appear in the short positions on the scan tool only while
the component is being commanded by the ECM or
scan tool.

ECM Output Diagnosis

Step

Action

Value(s)

Yes

No

1

Perform an Euro On-Board Diagnostic (EOBD)
System Check.
Is the check complete.

–

Go to Step 2

Go to “Euro

On-Board

Diagnostic

System Check”

2

Install the scan tool.
Is there a number 1 (=fault) below any of the
numbered positions in the OUTPUT DRIVERS?

–

Go to Step 3

Go to Step 4

3

Check for an open or shorted circuit in any
corresponding position (circuit) that contained a
number 1 and repair as necessary.
Is a repair necessary?

–

Go to Step 9

Go to Step 7

4

Command the output being checked with a scan tool
while watching the corresponding position for each
circuit.
Do any of the position changed to a 1?

–

Go to Step 6

Go to Step 5

5

Command the output being checked with a scan tool
while watching the corresponding position for each
circuit.
Does the component or function operate when
commanded?

–

Go to Step 9

Go to the

appropriate

component

table for repair

6

Repair the short to voltage in the corresponding
circuit for position (circuit) that displayed at a 1.
Is the repair complete?

–

Go to Step 9

–

7

Disconnect the electrical connector to the
component connected to the fault circuit.
Is a 1 still displayed in the corresponding OUTPUT
DRIVER position?

–

Go to Step 8

Go to the

appropriate

component

table for repair

8

Replace the Engine control Module (ECM).
Is the repair complete?

–

Go to Step 9

–

9

Operate the vehicle within the conditions under
which the original symptom was noted.
Does the system now operate properly?

–

System OK

Go to Step 2

ENGINE CONTROLS  1F – 21

MULTIPLE ECM INFORMATION SENSOR DTCS SET

Circuit Description

The Engine Control Module (ECM) monitors various
sensors to determine engine operating conditions. The
ECM controls fuel delivery, spark advance, transaxle op-
eration, and emission control device operation based on
the sensor inputs.

The ECM provides a sensor ground to all of the sensors.
The ECM applies 5 volts through a pull-up resistor and
monitors the voltage present between the sensor and
the resistor to determine the status of the Engine Cool-
ant Temperature (ECT) sensor, the Intake Air Tempera-
ture (IAT) sensor. The ECM provides the Electric
Exhaust Gas Recirculation (EEGR) Pintle Position Sen-
sor, the Throttle Position (TP) sensor, the Manifold Ab-
solute Pressure (MAP) sensor, and the Fuel Tank
Pressure Sensor with a 5 volt reference and a sensor
ground signal. The ECM monitors the separate feed-
back signals from these sensors to determine their oper-
ating status.

Diagnostic Aids

Be sure to inspect the ECM and the engine grounds for
being secure and clean.

A short to voltage in one of the sensor circuits can cause
one or more of the following DTCs to be set: P0108,
P0113, P0118, P0123, P1106.

If a sensor input circuit has been shorted to voltage, en-
sure that the sensor is not damaged. A damaged sensor
will continue to indicate a high or low voltage after the
affected circuit has been repaired. If the sensor has
been damaged, replace it.

An open in the sensor ground circuit between the ECM
and the splice will cause one or more of the following
DTCs to be set: P0108, P0113, P0118, P0123, P1106.

A short to ground in the 5 volt reference circuit or an
open in the 5 volt reference circuit between the ECM
and the splice will cause one or more of the following
DTCs to be set: P0107, P0112, P0117, P0122, P1107.

Check for the following conditions:

D

Inspect for a poor connection at the ECM. Inspect
harness connectors for backed-out terminals, im-
proper mating, broken locks, improperly formed or
damaged terminals, and poor terminal-to-wire con-
nection.

D

Inspect the wiring harness for damage. If the harness
appears to be OK, observe an affected sensor’s dis-
played value on the scan tool with the ignition ON and
the engine OFF while moving connectors and wiring
harnesses related to the affected sensors. A change
in the affected sensor’s displayed value will indicate
the location of the fault.