Chrysler PT Cruiser. Manual - part 309

TEST

ACTION

APPLICABILITY

Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Measure the resistance across the O2 Sensor Heater element component side.
NOTE: Heater Resistance Specification: 3 to 20 ohms for Upstream and
Downstream O2 Sensors.
Is the resistance within the specifications?

All

Yes

→ Go To 4

→ Replace the O2 Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Measure the resistance between an engine ground and the O2 Heater Ground circuit
in the O2 Sensor harness connector.
Is the resistance below 0.5 of an ohm?

All

Yes

→ Go To 5

→ Repair the open/high resistance in the O2 Heater Ground circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Disconnect the PCM harness connector.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING
THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMI-
NALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL
MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.
Measure the resistance of the O2 Heater Control circuit from the O2 Sensor harness
connector to the appropriate terminal of special tool #8815.
Is the resistance below 0.5 of an ohm?

All

Yes

→ Go To 6

→ Repair the open/high resistance in the O2 Heater Control circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

NOTE: Before continuing, check the PCM harness connector terminals for
corrosion, damage, terminal push out. Repair as necessary.
If there are no possible causes remaining, view repair.

All

Repair

Replace and program the Powertrain Control Module in accor-
dance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

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P0135-O2 SENSOR 1/1 HEATER PERFORMANCE —

Continued

Symptom:

P0171-FUEL SYSTEM 1/1 LEAN

When Monitored and Set Condition:

P0171-FUEL SYSTEM 1/1 LEAN

When Monitored:

With the engine running in closed loop mode, the ambient/battery

temperature above (-7°C)20°F, altitude below 8500 ft and fuel level greater than 15%.

Set Condition:

If the PCM multiplies short term compensation by long term adaptive and

a certain percentage is exceeded for two trips, a freeze frame is stored, the MIL illuminates
and a trouble code is stored.

POSSIBLE CAUSES

GOOD TRIP EQUAL TO ZERO

RESTRICTED FUEL SUPPLY LINE

FUEL PUMP INLET STRAINER PLUGGED

FUEL PUMP MODULE

O2 SENSOR

O2 SIGNAL CIRCUIT

O2 RETURN CIRCUIT

O2 SENSOR HEATER OPERATION

THROTTLE POSITION SENSOR SWEEP

MAP SENSOR OPERATION

ECT SENSOR OPERATION

ENGINE MECHANICAL PROBLEM

FUEL CONTAMINATION/EXHAUST LEAK

TEST

ACTION

APPLICABILITY

NOTE: Check for contaminants that may have damaged the O2 Sensor:
contaminated fuel, unapproved silicone, oil and coolant.
NOTE: Diagnose any Misfire DTC(s) first, if set along with the fuel system
DTC.
Ignition on, engine not running.
With the DRBIII

t, read DTCs and record the related Freeze Frame data.

Is the Good Trip Counter displayed and equal to zero?

All

Yes

→ Go To 2

→ Refer to the INTERMITTENT CONDITION symptom in the

Driveability category.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

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DRIVEABILITY - NGC

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.
Ignition on, engine not running.
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.

NOTE: If one of the O2 Sensors Signal or Return circuits are shorted to
ground or voltage, all the other O2 Sensor voltage readings will be affected.
NOTE: After the repairs have been made, verify proper O2 Sensor operation.
If all the O2 Sensor voltage readings have not returned to normal, follow the
diagnostic procedure for the remaining O2 Sensors.
Start the engine.
Allow the engine to reach normal operating temperature.
With the DRBIII

t, read the O2 Sensor voltage.

Is the voltage switching between 2.5 and 3.4 volts?

All

Yes

→ Go To 4

→ Go To 9

Turn the ignition off.
NOTE: Allow the O2 Sensor to cool down before continuing the test. The O2
voltage should stabilize at 5.0 volts. Raising the hood may help in reducing
under hood temps.
Ignition on, engine not running.
With the DRBIII

t, actuate the O2 Heater Test.

With the DRBIII

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

Does the voltage stay above 4.5 volts?

All

Yes

→ Replace the O2 Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

→ Go To 5

Ignition on, engine not running.
With the DRBIII

t, read the TP Sensor voltage.

While monitoring the DRBIII

t, slowly open and close the throttle.

Does the voltage increase and decease smoothly?

All

Yes

→ Go To 6

→ Replace the Throttle Position Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

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P0171-FUEL SYSTEM 1/1 LEAN —

Continued

TEST

ACTION

APPLICABILITY

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 DRBIII

t reading within 19 of the Vacuum Gauge reading?

All

Yes

→ Go To 7

→ Replace the MAP Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

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)
Ignition on, engine not running.
With the DRBIII

t, read the Engine Coolant Temperature (ECT) 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 ECT Sensor value. The temperature value
change should be a smooth transition from start up to normal operating temperature
82°C (180°F). The value should reach at least 82°C (180°F).
Did the ECT value increase with a smooth transition and did it reach at least 82°C?

All

Yes

→ Go To 8

→ Replace the Engine Coolant Temperature Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

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.

→ Test Complete.

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