Daewoo Matiz (2003 year). Manual — part 52

1F – 118 ENGINE CONTROLS

MAA1F040

DIAGNOSTIC TROUBLE CODE (DTC) – P1231 FUEL PUMP RELAY HIGH

VOLTAGE

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

D

This DTC can be stored in “key-on” status.

D

A high voltage condition exists.

Action Taken when the DTC Sets

D

The Malfunction Indicator Lamp (MIL) will illuminate.

D

The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Records buffers.

D

A history DTC is stored.

D

Coolant fan turns ON.

Conditions for Clearing the MIL/DTC

D

The MIL will turn off after 4 consecutive ignition
cycles in which the diagnostic runs without a fault.

D

A history DTC will clear after 40 consecutive warm up
cycles without a fault.

D

DTC(s) can be cleared by using the scan tool.

D

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.

D

Backed-out terminals

D

Improper mating

D

Broken locks

D

Improperly formed

D

Damaged terminals

D

Poor terminals to wire connection

D

Physical damage to the wiring harness

ENGINE CONTROLS 1F – 119

DTC P1231 – Fuel Pump Relay High Voltage

Step

Action

Value(s)

Yes

No

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 7

Go 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 seconds

Go 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 seconds

Go to Step 11

Go 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 8

Go 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 9

Go 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 seconds

System OK

Go 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 seconds

System OK

Go to Step 10

1F – 120 ENGINE CONTROLS

DTC P1231 – Fuel Pump Relay High Voltage (Cont’d)

Step

Action

Value(s)

Yes

No

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 seconds

System OK

Go 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 12

Go 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

ENGINE CONTROLS 1F – 121

BLANK