DTC P0172 SYSTEM TOO RICH (BANK 1)
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DTC P0172 SYSTEM TOO RICH (BANK 1)
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DTC DETECTING CONDITION:
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Two consecutive driving cycles with fault
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GENERAL DESCRIPTION
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TROUBLE SYMPTOM:
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Poor driving performance
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Important
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After repair
or replacement of faulty parts, conduct Clear Memory Mode
and Inspection Mode
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CHECK EXHAUST SYSTEM.
Are there holes or
loose bolts on exhaust system?
Repair the exhaust system.
CHECK AIR INTAKE SYSTEM.
Are there holes,
loose bolts or disconnection of hose on air intake system?
Repair the air intake system.
CHECK FUEL PRESSURE.
Warning
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Place “NO FIRE” signs
near the working area.
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Be careful not to spill fuel on the floor.
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Release the fuel pressure.
Connect the connector to fuel pump relay.
Disconnect the fuel delivery hose from fuel filter,
and connect fuel pressure gauge.
Install the fuel filler cap.
Start the engine and idle while gear position is neutral.
Measure the fuel pressure while disconnecting pressure
regulator vacuum hose from intake manifold.
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Warning
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Before removing the fuel pressure
gauge, release fuel pressure.
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Note
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If the fuel pressure does not increase,
squeeze fuel return hose 2 to 3 times, then measure fuel pressure
again.
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Is the measured value
284 — 314 kPa (2.9 — 3.2 kg/cm
2
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41 — 46 psi)?
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Repair the following items.
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Fuel pressure too high:
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Clogged
fuel return line or bent hose
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Improper
fuel pump discharge
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Clogged fuel supply line
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CHECK FUEL PRESSURE.
After connecting the pressure regulator vacuum hose, measure
fuel pressure.
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Warning
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Before removing the fuel pressure
gauge, release fuel pressure.
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Note
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If the fuel pressure does not increase, squeeze fuel
return hose 2 to 3 times, then measure fuel pressure again.
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If out of specification as measured at this step, check
or replace the pressure regulator and pressure regulator vacuum
hose.
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Is the measured
value 206 — 235 kPa (2.1 — 2.4 kg/cm
2
,
30 — 34 psi)?
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Repair the following items.
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Fuel pressure too high:
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Faulty
pressure regulator
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Clogged fuel return line or bent hose
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Faulty
pressure regulator
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Improper fuel pump discharge
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Clogged fuel supply line
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CHECK ENGINE COOLANT TEMPERATURE SENSOR.
Start the engine and warm-up completely.
Read the data of engine coolant temperature sensor
signal using Vehicle Diagnostic Interface
or OBD-II general scan tool.
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Note
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Vehicle Diagnostic Interface
For detailed operation procedure, refer to the “READ
CURRENT DATA FOR ENGINE”.
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OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II General
Scan Tool Instruction Manual.
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Is the temperature more than 60°C (140°F)?
Replace the engine coolant temperature
sensor.
CHECK MASS AIR FLOW AND INTAKE AIR TEMPERATURE.
Start the engine and warm-up engine until coolant temperature
is greater than 60°C (140°F).
Place the shift lever in neutral position.
Turn the A/C switch to OFF.
Turn all accessory switches to OFF.
Read the data of mass air flow and intake air temperature
sensor signal using Vehicle Diagnostic
Interface or OBD-II general scan tool.
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Note
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Vehicle Diagnostic Interface
For detailed operation procedure, refer to the “READ
CURRENT DATA FOR ENGINE”.
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OBD-II general scan tool
For detailed operation procedure, refer to the OBD-II General
Scan Tool Instruction Manual.
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Is the measured value within the followings? Ignition
ON: 73.3 — 106.6 kPa (550 — 800 mmHg, 21.65 — 31.50
inHg) Idling: 24.0 — 41.3 kPa (180 — 310 mmHg,
7.09 — 12.20 inHg)
Replace the mass air flow and intake air
temperature sensor.
CHECK MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR.
Start the engine and warm-up engine until coolant temperature
is greater than 60°C (140°F).
Place the shift lever in neutral position.
Turn the A/C switch to OFF.
Turn all accessory switches to OFF.
Open the front hood.
Measure the ambient temperature.
Read the data of mass air flow and intake air temperature
sensor signal using Vehicle Diagnostic
Interface or OBD-II general scan tool.
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Note
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Vehicle Diagnostic Interface
For detailed operation procedure, refer to the “READ
CURRENT DATA FOR ENGINE”.
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OBD-II general scan tool
For detailed operation procedure, refer to the OBD-II General
Scan Tool Instruction Manual.
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Subtract ambient temperature from intake air temperature.
Is the obtained value −10°C — 50°C
(14°F — 122°F)?
Contact Service Center.
Check the mass air flow and intake air
temperature sensor.
