Chrysler PT Cruiser. Manual - part 249

Symptom:

P0171-1/1 FUEL SYSTEM LEAN

When Monitored and Set Condition:

P0171-1/1 FUEL SYSTEM LEAN

When Monitored:

With the engine running in closed loop mode, the fuel level >15%,

atmospheric pressure >700 hpa, battery voltage >9.0 volts, air temp >-17.8°C (0°F) <-7°C
(19.4°F), coolant temp >69.75°C (157.6°F), MAF >0, canister load <50%, purge command =
0 or max, and no ECT, IAT, or MAP Sensor nor Canister Purge Solenoid DTCs present.

Set Condition:

If fuel correction is 25% or higher, this DTC is set whenever the fault is

detected and the MIL is turned on after the second trip with the fault present.

POSSIBLE CAUSES

INTERMITTENT CONDITION

RESTRICTED FUEL SUPPLY LINE

FUEL PUMP INLET STRAINER PLUGGED

FUEL PUMP MODULE

O2 SENSOR HEATER OPERATION

MAP SENSOR OPERATION

ECT SENSOR OPERATION

ENGINE MECHANICAL PROBLEM

TEST

ACTION

APPLICABILITY

NOTE: Check for contaminants that may have damaged the O2 Sensor:
contaminated fuel, unapproved silicone, oil and coolant.
Turn the ignition on.
With the DRBIII

t, read DTCs.

Does the Good Trip Indicator display NO?

All

Yes

→ Go To 2

→ Go To 10

DRIVEABILITY - 1.6L GAS

TEST

ACTION

APPLICABILITY

Warning: The fuel system is under a constant pressure (even with the engine
off). Before testing or servicing any fuel system hose, fitting or line, the fuel
system pressure must be released.
Install a fuel pressure gauge to the fuel rail.
Turn the ignition on.
With the DRBIII

t, actuate the ASD Fuel System test and observe the fuel pressure

gauge.
NOTE: Fuel pressure specification is 400 KPa +/- 34 KPa (58 psi +/- 5 psi).
Turn the ignition off.
Choose a conclusion that best matches your fuel pressure reading.

All

Within Specification

Go To

Below Specification

Go To

Caution: Stop All Actuations.

Turn the ignition off.
NOTE: Allow the O2 Sensor voltage to stabilize between 0.4 to 0.6 volts
before continuing this test.
Turn the ignition on.
With the DRBIII

t, actuate the O2 Heater Relay.

With the DRBIII

t, monitor O2 Sensor voltage for at least 2 minutes.

Does the voltage stay between 0.4 and 0.6

All

Yes

→ Replace the O2 Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.

→ Go To 4

Turn the ignition off.
Connect a Vacuum Gauge to a Manifold Vacuum source.
Start the engine.
Allow the engine to idle.
Note: If engine will not idle, maintain a constant RPM above idle.
With the DRBIII

t in Sensors, read the MAP Sensor vacuum value.

Is the DRB reading within 1

9 of the Vacuum Gauge reading?

All

Yes

→ Go To 5

→ Replace the MAP Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.

DRIVEABILITY - 1.6L GAS

P0171-1/1 FUEL SYSTEM LEAN —

Continued

TEST

ACTION

APPLICABILITY

Note: For this test to be valid, the thermostat must be operating correctly.
Note: This test works best if performed on a cold engine (cold soak)
Turn the ignition on.
With the DRBIII

t, read the Engine Coolant Temperature Sensor value. If the engine

was allowed to sit overnight (cold soak), the temperature value should be a sensible
value that is somewhere close to the ambient temperature.
Note: If engine coolant temperature is above 82°C (180°F), allow the engine
to cool until 65°C (150°F) is reached.
Start the Engine.
During engine warm-up, monitor the Engine Coolant Temperature value. The temp
value change should be a smooth transition from start up to normal operating temp
82°C (180°F). The value should reach at least 82°C (180°F).
Did the Engine Coolant Temperature value increase a smooth transition and did it
reach at least 82°C

All

Yes

→ Go To 6

→ Replace the Engine Coolant Temperature Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.

Check for any of the following conditions/mechanical problems.
AIR INDUCTION SYSTEM - must be free from leaks.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
FUEL INJECTOR - plugged or restricted injector; control wire not connected to
correct injector
Are there any engine mechanical problems?

All

Yes

→ Repair as necessary.

Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.

→ Test Complete.

Turn the ignition off.
Warning: The fuel system is under a constant pressure (even with the engine
off). Before testing or servicing any fuel system hose, fitting or line, the fuel
system pressure must be released.
Raise vehicle on hoist, and disconnect the fuel pressure line at the fuel pump module.
Install special 5/16 fuel line adapter tool #6539 between disconnected fuel line and
the fuel pump module.
Attach a fuel pressure test gauge to the T fitting on tool #6539.
Turn the ignition on.
With the DRBIII

t, actuate the ASD Fuel System test and observe the fuel pressure

gauge.
NOTE: Fuel pressure specification is 400 KPa +/- 34 KPa (58 psi +/- 5 psi).
Is the fuel pressure within specification?

All

Yes

→ Repair or replace fuel supply line as necessary.

Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.

→ Go To 8

Caution: Stop All Actuations.

DRIVEABILITY - 1.6L GAS

P0171-1/1 FUEL SYSTEM LEAN —

Continued

TEST

ACTION

APPLICABILITY

Turn the ignition off.
WARNING: The fuel system is under a constant pressure (even with the
engine off). Before testing or servicing any fuel system hose, fitting or line,
the fuel system pressure must be released.
Remove the Fuel Pump Module and inspect the Fuel Inlet Strainer.
Is the Fuel Inlet Strainer plugged?

All

Yes

→ Replace the Fuel Pump Inlet Strainer.

Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.

→ Go To 9

If there are no possible causes remaining, view repair.

All

Repair

Replace the Fuel Pump Module.
Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.

NOTE: Check for contaminants that may have damaged the O2 Sensor.
Check for contaminated fuel, unapproved silicone, oil, and coolant.
WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS, OR FAN(S). DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help identify the intermittent condition.
With the engine running at normal operating temperature, monitor the DRBIII
parameters related to this DTC.
Review Freeze Frame information. Try to duplicate the conditions under which the
DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for any broken, bent,
pushed out, or corroded terminals.
Were any of the above conditions present?

All

Yes

→ Repair as necessary.

Perform POWERTRAIN VERIFICATION TEST VER - 5 - 1.6L.

→ Test Complete.

DRIVEABILITY - 1.6L GAS

P0171-1/1 FUEL SYSTEM LEAN —

Continued

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