1F – 556IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P1392 – G Sensor Rough Road Low Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Install a scan tool to the Data Link Connector
(DLC).
3. Turn the ignition ON, with the engine OFF.
4. Observe the ROUGH ROAD value displayed
on the scan tool.
Is the ROUGH ROAD value near the specified val-
ue?0 vGo to Step 4Go to Step 3
31. Review and record the scan tool Failure Re-
cords data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using the scan tool, monitor specific Diagnostic
Trouble Code (DTC) info for DTC P1392.
Does the scan tool indicate that DTC P1392 failed?–Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition OFF.
2. Disconnect the G sensor electrical connector.
3. Turn the ignition ON, with the engine OFF.
4. Jumper the 5 volt reference circuit, terminal A
and the G sensor signal circuit, terminal B to-
gether at the G sensor harness connector.
5. Observe the G sensor value displayed on the
scan tool.
Is the G sensor value near the specified value?4.95 vGo to Step 9Go to Step 5
51. Turn the ignition OFF.
2. Disconnect the Engine Control Module (ECM)
and check the 5 volt reference circuit for an
open or short to ground and repair as needed.
Is the repair complete?–Go to Step 11Go to Step 6
6Check the 5 volt reference circuit for poor connection
at the ECM and repair or replace as needed.
Is the repair complete?–Go to Step 11Go to Step 7
71. Turn the ignition OFF.
2. Disconnect the ECM and check the G sensor
signal circuit for an open, a short to ground, or
a short to the sensor ground circuit and repair
as needed.
Is the repair complete?–Go to Step 11Go to Step 8
8Check the G sensor signal circuit for a poor connec-
tion at the ECM and repair as needed.
Is the repair complete?–Go to Step 11Go to Step 10
9Replace the G sensor.
Is the repair complete?–Go to Step 11–
101. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 11–
ENGINE CONTROLS 1F – 559
DAEWOO V–121 BL4
DTC P1393 – G Sensor Rough Road High Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Install a scan tool to the Data Link Connector
(DLC).
3. Start and idle the engine.
4. Observe the ROUGH ROAD value displayed
on the scan tool.
Is the ROUGH ROAD value near the specified val-
ue?4.5 vGo to Step 4Go to Step 3
31. Review and record the scan tool Failure Re-
cords data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using the scan tool, monitor specific Diagnostic
Trouble Code (DTC) info for DTC P1393.
Does the scan tool indicate that DTC P1393 failed?–Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition OFF.
2. Disconnect the G sensor electrical connector.
3. Turn the ignition ON, with the engine OFF.
4. Note the G sensor voltage displayed on the
scan tool.
Is the G sensor value near the specified value?0 vGo to Step 5Go to Step 6
5Probe the sensor ground circuit terminal C with a test
light to B+.
Is the test light ON?–Go to Step 7Go to Step 9
6Check the G sensor signal circuit for a short to volt-
age or a short to the 5 volt reference circuit and re-
pair as needed.
Is the repair complete?–Go to Step 12Go to Step 11
7Check for a poor sensor ground terminal connection
at the G sensor electrical connector.
Is the repair complete?–Go to Step 12Go to Step 8
8Check for a poor sensor ground terminal connection
at the Engine Control Module (ECM) and repair as
needed.
Is the repair complete?–Go to Step 12Go to Step 10
9Check the G sensor ground circuit for an open and
repair as needed.
Is the repair complete?–Go to Step 12Go to Step 10
101. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 12–
11Replace the G sensor.
Is the repair complete?–Go to Step 12Go to Step 10
1F – 566IENGINE CONTROLS
DAEWOO V–121 BL4
freeze frame data to determine if the DTC set when the ve-
hicle was cold by viewing the Engine Coolant Temperature
(ECT).
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.
1. The On–Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
2. Commanding the EGR valve open determines
whether the EGR system can control the EGR
valve accurately and if the fault is present.
3. When the EGR valve electrical connector is discon-
nected, the scan tool should display the Actual
EGR Position as 0%. If it does not, the fault lies
either in the EGR signal circuit or the ECM.
5. If the ERG valve 5 volt reference is shorted to volt-
age, the Digital Voltmeter (DVM) will read battery
voltage and additional DTCs may be set and engine
performance will be poor.6. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.
10. An open or poor connection condition may have
caused this DTC to set. Be sure to check the termi-
nals for being backed out, improperly formed or
damaged, and for poor tension.
11. All circuits to the EGR valve are OK at this point.
The fault lies internally in the EGR valve and there-
fore must be replaced. Be sure all gasket material
is removed from the EGR mounting surface. Even
a small amount of material may cause a DTC
P0401 to set.
12. Check the terminals for being backed out, improp-
erly formed or damaged, and for poor tension.
13. Clearing DTCs is a very important step for this
diagnostic. The clearing function allows the EGR
valve to relearn a new pintle position as the old
pintle position was inaccurate due to the failure that
caused the DTC. The DTC must be cleared with
the ignition ON, engine OFF or when the engine is
idling. If the ECM sees a EGR command, the new
pintle will not be learned.
14. If no malfunctions have been found at this point and
no additional DTCs were set, refer to ”Diagnostic
Aids” in this section for additional checks and infor-
mation.
DTC P1404 – Exhaust Gas Recirculation Closed Valve Pintle Error
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was tht check Performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
3. Command the Exhaust Gas Recirculation
(EGR) valve to the specific values.
Does the Actual EGR Position follow the Desired
EGR Position?25%, 50%,
75%, 100%Go to Step 13Go to Step 3
31. Turn the ignition OFF.
2. Disconnect the EGR valve.
Is the Actual EGR Position near the specified value?100%Go to Step 4Go to Step 5
4Check the signal circuit terminal 3 at the EGR wiring
harness connector for a short to voltage and repair
as needed.
Is a repair complete?–Go to Step 13Go to Step 6
5With a voltmeter connected to the ground, probe the
5 volt reference circuit at terminal 4 of the EGR valve
wiring harness connector.
Is the voltage near the specified value?5 vGo to Step 7Go to Step 8
61. Turn the ignition OFF.
2. Replace the Engine Control Module (ECM).
Is the repair complete?–Go to Step 13–
ENGINE CONTROLS 1F – 569
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1607
LOWER POWER COUNTER RESET
Circuit Description
The Engine Control Module (ECM) is the control center of
the fuel injection system. It constantly looks at the informa-
tion from various sensors, and controls the systems that
affect vehicle performance. The ECM also performs the
diagnostic function of the system. It can recognize opera-
tional problems, alert the driver through the Malfunction In-
dicator Lamp (MIL) (Check Engine), and store a Diagnos-
tic Trouble Code (DTC) or DTCs which identify the
problem areas to aid the technician in making repairs. An
Electrically Erasable Programmable Read Only Memory
(EEPROM) is used to house the program information and
the calibrations required for engine, transmission, and
powertrain diagnostics operation. The ECM monitors EE-
PROM reset flag and Lower Power Counter I/C overflow
bits. If the ECM detects if Lower Power Counter I/C has
been reset due to battery disconnect or Lower Power
Counter I/C malfunction, the Diagnostic Trouble Code
(DTC) will stored.Conditions for Setting the DTC
S Ignition switch is turned to ON.
S Engine is not running.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
DTC P1607 – Lower Power Counter Reset
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Replace the Engine Control Module (ECM).
Is the repair complete?–Go to Step 3–
31. 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 4Go to Step 2
4Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK
1F – 572IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1650
SPI COMMUNICATION BETWEEN ERROR WITH SIDM
CHIP
Circuit Description
The Engine Control Module (ECM) is the control center of
the fuel injection system. It constantly looks at the informa-
tion from various sensors, and controls the systems that
affect vehicle performance. The ECM also performs the
diagnostic function of the system. It can recognize opera-
tional problems, alert the driver through the Malfunction In-
dicator Lamp (MIL) (Check Engine), and store a Diagnos-
tic Trouble Code (DTC) or DTCs which identify the
problem areas to aid the technician in making repairs. An
Electrically Erasable Programmable Read Only Memory
(EEPROM) is used to house the program information and
the calibrations required for engine, transmission, and
powertrain diagnostics operation. The Diagnostic Trouble
Code (DTC) will stored, when the ECM detects SPI com-
munication between main CPU and output driver I/C is
corrupted.
Conditions for Setting the DTCS Ignition switch is turned to ON.
S Battery voltage is greater than 11 volts.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
DTC P1650 – SPI Communication Between Error with SIDM Chip
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Replace the Engine Control Module (ECM).
Is the repair complete?–Go to Step 3–
31. 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 4Go to Step 2
4Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK
ENGINE CONTROLS 1F – 573
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1655
SPI COMMUNICATION BETWEEN ERROR WITH PSVI
CHIP
Circuit Description
The Engine Control Module (ECM) is the control center of
the fuel injection system. It constantly looks at the informa-
tion from various sensors, and controls the systems that
affect vehicle performance. The ECM also performs the
diagnostic function of the system. It can recognize opera-
tional problems, alert the driver through the Malfunction In-
dicator Lamp (MIL) (Check Engine), and store a Diagnos-
tic Trouble Code (DTC) or DTCs which identify the
problem areas to aid the technician in making repairs. An
Electrically Erasable Programmable Read Only Memory
(EEPROM) is used to house the program information and
the calibrations required for engine, transmission, and
powertrain diagnostics operation. The Diagnostic Trouble
Code (DTC) will stored, when the ECM detects corrupted
serial peripheral interface (SPI) comunication between
main CPU and output driver I/C.
Conditions for Setting the DTCS Ignition switch is turned to ON.
S Battery voltage is greater than 11 volts.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.
S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
DTC P1655 – SPI Communication Between Error with PSVI Chip
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Turn the ignition OFF.
2. Replace the Engine Control Module (ECM).
Is the repair complete?–Go to Step 3–
31. 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 4Go to Step 2
4Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK
1F – 574IENGINE CONTROLS
DAEWOO V–121 BL4
SYMPTOM DIAGNOSIS
IMPORTANT PRELIMINARY CHECKS
Important : Several symptom procedures call for a careful visual/physical inspection. Always perform the visual/physical
test first. Visual inspections may lead to correcting a problem without further checks and can save valuable time.
Step
ActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the check complete?–Go toStep 2Go to”On–
Board Diagnos-
tic System
Check”
21. Inspect all of the engine control module (ECM)
ground connections.
2. Inspect all of the vacuum hoses for splits,
kinks, and proper connections.
3. Check for air leaks at all of the mounting areas
of the intake manifold sealing surfaces.
4. Inspect the ignition wires for cracking, hard-
ness, proper routing, and carbon tracking.
5. Inspect the wiring for proper connections,
pinches, and cuts.
Are all checks complete?–Go to Appropri-
ate Symptom
Table–
INTERMITTENTS
Definition : The problem may or may not illuminate the
Malfunction Indicator Lamp (MIL) or store a diagnostic
trouble code (DTC).Important : Do not use the DTC tables for intermittent
problems. A fault must be present in order to locate the
problem. If a fault is intermittent, use of DTC tables may
result in the replacement of good parts.
Step
ActionValue(s)YesNo
1Were the Important Preliminary Checks performed?–Go toStep 2Go to
”Important Pre-
liminary
Checks”
21. Perform a careful inspection of any suspect
circuits.
2. Inspect for poor mating of the connector
halves, or terminals not fully seated into the
connector body.
3. Inspect for improperly formed or damaged ter-
minals.
4. Inspect for poor terminal to wire connections.
This requires removing the terminal from the
connector body to inspect it.
Are any problems present?–Go toStep 3Go toStep 4
3Repair the electrical connections as needed.
Is the repair complete?–System OK–
4Road test the vehicle with a voltmeter connected to
a suspected circuit or a scan tool connected to the
Data Link Connector (DLC).
Did the voltmeter or the scan tool indicate an abnor-
mal voltage or scan reading?–Go toStep 5Go toStep 6
ENGINE CONTROLS 1F – 575
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
5Replace the sensor in the affected circuit, if a Diag-
nostic Trouble Code (DTC) was stored for this circuit
(except for the DTCs P0171 and P0172.
Is the repair complete?–System OK–
6Does an intermittent Malfunction Indicator Lamp
(MIL) or DTC occur?–Go toStep 7Go toStep 8
71. Check for a faulty relay, electronic control mod-
ule (ECM) driven solenoid, or switch.
2. Check for improper installation of electrical de-
vices, such as lights, two–way radios, electric
motors, etc.
3. Inspect the ignition control wires for proper
routing (away from ignition wires, ignition sys-
tem components, and the generator).
4. Check for a short–to–ground in the MIL circuit
or the DLC ”test” terminal.
5. Inspect the ECM ground connections.
6. Correct or repair the affected circuits as need-
ed.
Is the repair complete?–System OK–
81. Check for a loss of DTC memory.
2. 2. Disconnect the Throttle Position Sensor.
3. Run the engine at idle until the MIL comes on.
4. Turn the ignition OFF.
Is DTC P0122 stored in memory?–Go toStep 10Go toStep 9
9Replace the ECM.
Is the repair complete?–System OK–
10Does the vehicle stall while driving?–Go toStep 11Go toStep 12
11Monitor the Front Heated Oxygen Sensor (HO2S1)
and the injector base pulse width with the scan tool.
Does the scan tool display a steady low voltage
(about 0 mv) for the HO2S1 sensor with the control
module commanding an injector base pulse width of
the value specified?8 msGo toStep 9Go toStep 12
121. Check for an open diode across the A/C clutch
and for other open diodes.
2. Repair or replace any components as needed.
Is the repair complete?–System OK–