
Symptom:
* CHECKING EVAPORATIVE EMISSION SYSTEM
POSSIBLE CAUSES
EVAP PURGE SOLENOID DEFECTIVE
EVAP PURGE SOLENOID DEFECTIVE
EVAPORATIVE CANISTER DEFECTIVE
EVAPORATIVE EMISSION VACUUM HOSE OBSERVABLE DEFECT
VACUUM LINE OBSERVABLE DEFECT
VACUUM LINE PLUGGED
VACUUM LINE PLUGGED
TEST PASSED
TEST ACTION APPLICABILITY
1 Ignition Off
Note: Carefully inspect all Vacuum Hoses for proper routing and for
pinched or plugged Hoses from the engine to the PPS to the Gas Tank.
Are all the Vacuum Hoses OK?All
Ye s®Go To 2
No®Repair the Vacuum Hoses as necessary.
Perform Powertrain Verification Test VER-2A.
2 Ignition Off
Start the engine and allow it to reach normal operating temperature 76 deg C (170
deg. F).
Turn ignition off.
Disconnect the Purge Vacuum Hose at the Solenoid that goes to the Canister.
Start the engine.
Note: There should be no flow through the Solenoid from 1 to 2 minutes.
Is the PPS allowing vacuum through the Solenoid within 1 minute?All
Ye s®Go To 3
No®Go To 6
3 Ignition Off
Inspect the line from the PPS to the Canister.
Is the line disconnected, ripped or cut?All
Ye s®Repair the Line and replace the Purge Solenoid.
Perform Powertrain Verification Test VER-2A.
No®Go To 4
4 Ignition Off
Remove the Purge Solenoid and tap the ports against a clean solid surface.
Did any foreign material fall out?All
Ye s®Go To 5
No®Replace the Evap Purge Solenoid.
Perform Powertrain Verification Test VER-6A.
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DRIVEABILITY
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TEST ACTION APPLICABILITY
5 If there are no potential causes remaining, the Vacuum Line is assumed to be
defective.
View repair options.All
Repair
Clean out the Line and replace the PPS and Canister.
Perform Powertrain Verification Test VER-2A.
6 Ignition Off
Disconnect the Purge Vacuum Hose at the Solenoid that goes to the Canister.
Note: In the next steps, do not use more that five PSI.
Attempt to blow air through the Vacuum Line that goes to the canister.
Does the Canister and Vacuum Line allow air to pass?All
Ye s®Purge Solenoid and hoses OK. Test passed.
No®Go To 7
7 Ignition Off
Start the engine and allow it to reach normal operating temperature 76 deg C (170
deg F).
Turn ignition off.
Disconnect the Purge Vacuum Hose at the Solenoid that goes to the Canister.
Start the engine.
Note: After 90 seconds, the Purge Solenoid will allow vacuum to cycle
intermittently at a steady rate.
Is the Evap Solenoid allowing vacuum to cycle through intermittently at a steady
rate?All
Ye s®Go To 8
No®Replace the Purge Solenoid.
Perform Powertrain Verification Test VER-6A.
8 Ignition Off
Note: In the next steps, do not use more than five psi.
Disconnect the Purge Vacuum Hose at the Solenoid that goes to the Canister.
Disconnect the Vacuum Line at the Canister that goes to the EVAP Solenoid.
Attempt to blow air through the Vacuum Line that goes to the Canister.
Does the Vacuum Line allow air to pass?All
Ye s®Go To 9
No®Repair or replace the Vacuum Line.
Perform Powertrain Verification Test VER-2A.
9 If there are no potential causes remaining, the Evaporative Canister is assumed to be
defective.
View repair options.All
Repair
Replace the Evaporative Canister.
Perform Powertrain Verification Test VER-2A.
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DRIVEABILITY
* CHECKING EVAPORATIVE EMISSION SYSTEM ÐContinued
ProCarManuals.com

Symptom:
* CHECKING FOR OXYGEN SENSOR SWITCHING
POSSIBLE CAUSES
O2 SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
ENGINE VACUUM ABNORMAL
FUEL DELIVERY SYSTEM DEFECTIVE
O2 SENSOR DEFECTIVE
AIR INLET SYSTEM RESTRICTED
TEST ACTION APPLICABILITY
1 Engine Running
Note: the Engine must be running and at normal operating temperature.
Note: The Downstream O2 Sensor should switch slower than the Upstream
O2 Sensor.
With the DRB, read the O2 Sensor voltages for 10 seconds or more.
Are the O2 Sensor voltages switching normally?All
Ye s®Test Complete.
No®Go To 2
2 Engine Running
Note: The Engine must be running and at normal operating temperature.
Note: The Downstream O2 Sensor should switch slower than the Upstream
O2 Sensor.
With the DRB, read the O2 Sensor voltages for 10 seconds or more.
Is the Upstream O2 Sensor locked9LEAN9?All
Ye s®Go To 3
No®Go To 9
3 Ignition On, Engine Not Running
With the DRB, read the O2 Sensor Signal voltages.
Is the voltage below 0.10 volts for the Upstream or Downstream O2 Sensor?All
Ye s®Go To 4
No®Go To 7
4 Engine Running
Allow the Engine to idle.
Inspect the Engine for any abnormal vacuum conditions.
Are there any abnormal vacuum conditions?All
Ye s®Repair abnormal Engine Vacuum condition as required.
Perform Powertrain Verification Test VER-2A.
No®Go To 5
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DRIVEABILITY
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TEST ACTION APPLICABILITY
5 Ignition Off
Disconnect the Upstream or Downstream O2 Sensor Connector that the voltage is
below 0.10 volts.
Note: Check connectors - Clean/repair as necessary.
Disconnect the Powertrain Control Module.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance between the O2 Sensor Signal Circuit
and a good ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the O2 Sensor Signal Circuit for a short to ground.
Perform Powertrain Verification Test VER-2A.
No®Go To 6
6 If there are no potential causes remaining, the Upstream or Downstream O2 Sensor
is assumed to be defective.
View repair options.All
Repair
Replace the Upstream or Downstream O2 Sensor that was below
0.10 volts.
Perform Powertrain Verification Test VER-2A.
7 Engine Running
Allow the Engine to idle.
Inspect the Engine for any abnormal vacuum conditions.
Are there any abnormal vacuum conditions?All
Ye s®Repair abnormal Engine Vacuum condition as required.
Perform Powertrain Verification Test VER-2A.
No®Go To 8
8 Engine Running
With the DRB, reset the Adaptive Fuel Memory.
Note: The engine must be running and at normal operating temperature.
Note: The Downstream O2 Sensor should switch slower than the Upstream
O2 Sensor.
With the DRB, read the O2 Sensor voltages for 10 seconds or more.
Are the O2 Sensor voltages switching normally?All
Ye s®Test Complete.
No®Refer to symptom * CHECKING THE ENGINE MECHANICAL
SYSTEMS in the DRIVEABILITY category.
9 Ignition Off
Install a Fuel Pressure Gauge to the Fuel Line. Use special tools if necessary.
Turn ignition on.
With the DRB, actuate the ASD Fuel System Test.
Allow Fuel Pressure to stabilize.
With the DRB, stop Fuel System Test. Monitor the Pressure Gauge for 1 minute.
Is the Fuel Pressure below 10 psi?All
Ye s®If Fuel Pump and Lines are OK, replace leaking Injector(s) as
necessary.
Perform Powertrain Verification Test VER-2A.
No®Go To 10
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DRIVEABILITY
* CHECKING FOR OXYGEN SENSOR SWITCHING ÐContinued
ProCarManuals.com

TEST ACTION APPLICABILITY
10 Ignition Off
Inspect the Air Filter and Inlet Ducts for restriction(s).
Were there any restrictions?All
Ye s®Repair or replace the Air Inlet System as necessary.
Perform Powertrain Verification Test VER-2A.
No®Refer to symptom * CHECKING THE ENGINE MECHANICAL
SYSTEMS in the DRIVEABILITY category.
236
DRIVEABILITY
* CHECKING FOR OXYGEN SENSOR SWITCHING ÐContinued
ProCarManuals.com

Symptom:
* CHECKING FUEL DELIVERY
POSSIBLE CAUSES
FUEL LINE RESTRICTED
FUEL FILTER DEFECTIVE
FUEL LINE RESTRICTED
FUEL PRESSURE REGULATOR DEFECTIVE
FUEL PUMP/REGULATOR ASSEMBLY DEFECTIVE
FUEL RETURN LINE DEFECTIVE
FUEL PUMP/REGULATOR ASSEMBLY DEFECTIVE
TEST ACTION APPLICABILITY
1 Ignition Off
Warning: The Fuel System must be opened and may be under high pressure.
Release the Fuel Pressure.
Connect a Fuel Pressure Gauge to test port.
Ignition On, Engine Not Running
With the DRB, actuate Fuel System. Fuel Pressure should be 43 to 53 psi.
Fuel Pressure should be 43 to 53 psi.
Is the Fuel Pressure within the specification?ENGINE - 2.4L I-4
DOHC and/or EN-
GINE - 3.3L V6
and/or ENGINE -
3.3L V6 FFV and/or
ENGINE - 3.8L V6
Ye s®Go To 2
No®Go To 5
2 Ignition Off
Note: Make sure the Gear Lever is in neutral, and the Park Brakes engaged.
Start the engine.
Monitor the Fuel Pressure Gauge in the next step.
While monitoring the pressure, momentarily snap Throttle wide open raising RPM to
above 3000.
Did the fuel pressure drop below 35 psi at all?All
Ye s®Go To 3
No®Test Complete.
3 Ignition Off
Inspect the Chassis Fuel Supply Line to the engine for a kink or restriction.
Is the line kinked or restricted?All
Ye s®Release the fuel pressure. Repair the Fuel Line as necessary.
Perform Powertrain Verification Test VER-2A.
No®Go To 4
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DRIVEABILITY
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TEST ACTION APPLICABILITY
4 Ignition Off
Warning: The Fuel System must be opened and may be under high pressure.
Release the fuel pressure.
Remove the Fuel Pressure Gauge from the Fuel Rail.
Adjust a shop air hose to 40 psi.
Remove the Fuel Filter.
Using shop air, inspect the Fuel Filter passage by attempting to blow air through
inlet.
Is the Fuel Filter restricted?All
Ye s®Replace the Fuel Filter.
Perform Powertrain Verification Test VER-2A.
No®Replace the Fuel Pump and Regulator Assembly.
Perform Powertrain Verification Test VER-2A.
5 Ignition Off.
Warning: The Fuel System must be opened and may be under high pressure.
Release the Fuel Pressure.
Connect a Fuel Pressure Gauge to test port.
Ignition On, Engine Not Running.
With the DRB, actuate Fuel System. Fuel Pressure should be 43 to 53 psi for Gasoline
Engines and 50 to 60 psi for Flexible Fuel Vehicle.
Record the Fuel Pressure reading.
Is the Fuel Pressure above the specification?ENGINE - 2.4L I-4
DOHC and/or EN-
GINE - 3.3L V6
and/or ENGINE -
3.3L V6 FFV and/or
ENGINE - 3.8L V6
Ye s®Go To 6
No®Go To 8
6 Ignition Off
Warning: The Fuel System must be opened and may be under high pressure.
Release the fuel pressure.
Remove the Fuel Pressure Gauge from the Fuel Rail.
Remove the Fuel Return Line between the Fuel Tank and Filter.
Adjust a shop air hose to 40 psi.
Using shop air, inspect the Fuel Line by attempting to blow air through it.
Is the Fuel Return Line restricted?All
Ye s®Replace the Fuel Return Line.
Perform Powertrain Verification Test VER-2A.
No®Go To 7
7 If there are no potential causes remaining, the Fuel Pressure Regulator is assumed
to be defective.
View repair options.All
Repair
Replace the Fuel Pressure Regulator.
Perform Powertrain Verification Test VER-2A.
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DRIVEABILITY
* CHECKING FUEL DELIVERY ÐContinued
ProCarManuals.com

TEST ACTION APPLICABILITY
8 Ignition Off
Inspect the Chassis Fuel Supply Line to engine for a kink or restriction.
Is the Line kinked or restricted?ENGINE - 2.4L I-4
DOHC and/or EN-
GINE - 3.3L V6
and/or ENGINE -
3.3L V6 FFV and/or
ENGINE - 3.8L V6
Ye s®Release the Fuel Pressure. Repair the Fuel Line as necessary.
Perform Powertrain Verification Test VER-2A.
No®Go To 9
9 Ignition Off
Warning: The Fuel System must be opened and may be under high pressure.
Release the fuel pressure.
Connect a Fuel Pressure Adapter and Gauge to Supply Line between Tank/Filter.
Turn ignition on.
With the DRB, actuate the Fuel System test.
Is the Fuel Pressure at least 5 psi higher than previously recorded pressure?ENGINE - 2.4L I-4
DOHC and/or EN-
GINE - 3.3L V6
and/or ENGINE -
3.3L V6 FFV and/or
ENGINE - 3.8L V6
Ye s®Release the Fuel Pressure. Replace the Fuel Filter.
Perform Powertrain Verification Test VER-2A.
No®Go To 10
10 Ignition Off
Warning: The Fuel System must be opened and may be under high pressure.
Release the fuel pressure.
Connect a Fuel Pressure Adapter and Gauge to Supply Line between Tank/Filter.
Turn ignition on.
With the DRB, actuate the Fuel System test.
Is Fuel Pressure at least 5 psi higher than previously recorded pressure?ENGINE - 2.4L I-4
DOHC and/or EN-
GINE - 3.3L V6
and/or ENGINE -
3.3L V6 FFV and/or
ENGINE - 3.8L V6
Ye s®Test Complete.
No®Release the Fuel Pressure. Replace the Fuel Pump and Regulator
Assembly.
Perform Powertrain Verification Test VER-2A.
11 Ignition Off
Warning: The Fuel System must be opened and may be under high pressure.
Relieve the Fuel Pressure.
Tee-in Fuel Pressure Gauge into the Fuel Supply Hose using Tool #6433.
Turn ignition on.
With the DRB, actuate the ASD Fuel System test.
Is the Fuel Pressure between 43 and 53 psi?ENGINE - 3.0L V6
Ye s®Go To 12
No®Go To 15
12 Ignition Off
Note: Make sure the Gear Lever is in neutral, and the Park Brakes engaged.
Start the engine.
Monitor the Fuel Pressure Gauge in the next step.
While monitoring the pressure, momentarily snap Throttle wide open raising RPM to
above 3000.
Did the fuel pressure drop below 35 psi at all?All
Ye s®Go To 13
No®Test Complete.
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DRIVEABILITY
* CHECKING FUEL DELIVERY ÐContinued
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