
TEST ACTION APPLICABILITY
8 Turn the igntion off.
Disconnect the EGR Solenoid harness connector.
Turn the ignition on.
Using a 12 volt Test Light connected to ground, probe the Fused Ignition Switch
Output circuit in the EGR Solenoid harness connector.
Does the 12 volt test light illuminate?All
Ye s®Go To 9
No®Repair the Fused Ignition Switch Output circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
9 Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Turn the ignition on.
Measure the voltage of the EGR Solenoid Control circuit in the EGR Solenoid
connector.
Is the voltage above 1.0 volts?All
Ye s®Repair the EGR Solenoid Control circuit for a short to voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 10
10 Turn the ignition off.
Disconnect the PCM harness connector.
Disconnect the EGR Solenoid harness connector.
Measure the resistance of the EGR Solenoid Control circuit between the PCM
harness connector and the EGR Solenoid harness connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 11
No®Repair the EGR solenoid control circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
11 Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Using a 12-volt test light connected to 12-volts, probe the EGR Solenoid Control
circuit in the EGR Solenoid harness connector.
Turn the ignition on.
With the DRBIIIt, actuate the EGR Solenoid.
Observe the test light.
Does the test light flash on and off.All
Ye s®Inspect the EGR Solenoid Back Pressure hose and tube for
obstructions or damage. If OK, replace the EGR Solenoid.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Replace and program the Powertrain Control Module in accor-
dance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
126
DRIVEABILITY - GAS
P0401 - EGR SYSTEM FAILURE ÐContinued

TEST ACTION APPLICABILITY
12NOTE: Inspect the exhaust system for leaks.
WARNING: KEEP CLEAR OF THE ENGINE'S MOVING PARTS.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DRB Freeze Frame information. If possible, 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 broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
127
DRIVEABILITY - GAS
P0401 - EGR SYSTEM FAILURE ÐContinued

TEST ACTION APPLICABILITY
3 Turn the igntion off.
Disconnect the EGR Solenoid harness connector.
Turn the ignition on.
Using a 12 volt Test Light connected to ground, probe the Fused Ignition Switch
Output circuit in the EGR Solenoid harness connector.
Does the 12 volt test light illuminate?All
Ye s®Go To 4
No®Repair the Fused Ignition Switch Output circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
4 Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Turn the ignition on.
Measure the voltage of the EGR Solenoid Control circuit in the EGR Solenoid
connector.
Is the voltage above 1.0 volt?All
Ye s®Repair the EGR Solenoid Control circuit for a short to voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 5
5 Turn the ignition off.
Disconnect the PCM harness connector.
Disconnect the EGR Solenoid harness connector.
Measure the resistance of the EGR Solenoid Control circuit in the EGR Solenoid
harness connector to ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the EGR Solenoid Control circuirt for a short to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 6
6 Turn the ignition off.
Disconnect the PCM harness connector.
Disconnect the EGR Solenoid harness connector.
Measure the resistance of the EGR Solenoid Control circuit between the PCM
harness connector and the EGR Solenoid harness connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 7
No®Repair the EGR Solenoid Control circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
7 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.
129
DRIVEABILITY - GAS
P0403 - EGR SOLENOID CIRCUIT ÐContinued

TEST ACTION APPLICABILITY
8NOTE: Inspect the exhaust system for leaks.
WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DRB Freeze Frame information. If possible, 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 broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
130
DRIVEABILITY - GAS
P0403 - EGR SOLENOID CIRCUIT ÐContinued

TEST ACTION APPLICABILITY
3 Start the engine.
Inspect the exhaust for leak between the engine and the O2 sensor.
Inspect the exhaust for leaks between the engine and the appropriate rear O2 Sensor.
Are there any exhaust leaks?All
Ye s®Repair or replace the leaking exhaust parts as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 4
4 Check the exhaust for excessive smoke caused by an internal problem in the engine.
Is a engine mechanical condition present?All
Ye s®Repair the engine mechanical condition as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 5
5 A new rear O2 Sensor along with an aging front O2 Sensor may cause the DTC to set.
Review the vehicles repair history.
Has the rear O2 Sensor been replace without replacing the front O2 Sensor?All
Ye s®Replace the O2 Sensor as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 6
6 If there are no possible cause remaining, view repair. All
Repair
replace the Catalytic Converter.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
7WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: Check for contaminates that may have damaged the O2 Sensor and
Catalytic Converter: contaminated fuel, unapproved silicone, oil and cool-
ant, repair necessary.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
A new rear O2 Sensor along with a aging front O2 Sensor may cause the DTC to set.
Review repair history of the vehicle and repair as necessary.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DRB Freeze Frame information. If possible, 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 connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
132
DRIVEABILITY - GAS
P0420-1/1 CATALYTIC CONVERTER EFFICIENCY ÐContinued

TEST ACTION APPLICABILITY
8WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
Perform a wiggle test of the Evap Purge Solenoid wiring while the circuit is actuated
with the DRBIIIt. Listen for the solenoid to quit actuating. Also watch for the Good
Trip Counter to change to 0.
Review the DRB Freeze Frame information. If possible, 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 broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
135
DRIVEABILITY - GAS
P0441-EVAP PURGE FLOW MONITOR ÐContinued

TEST ACTION APPLICABILITY
3Note: A thorough visual inspection of the Evap system hoses, tubes, and
connections may save time in your diagnosis. Look for any physical damage
or signs of wetness at connections. The strong smell of fuel vapors may aid
diagnosis also.
To continue testing, you will need Miller Tool #6904A Ultrasonic Leak Detector.
NOTE: The LDP System Test should still be running. If the DRBIIIthas
timed out, restart the System Test.
Using Miller Tool #6872A, set the Pressure/Hold Switch to Open, and the Vent Switch
to Closed. Turn the pump timer on to pressurize/re-pressurize the Evap System.
Using the Ultrasonic Leak Detector, start listening for leaks in the Evap System.
Carefully leak test all hoses, tubes, and connections.
Were any leaks heard with the Ultrasonic Leak Detector?All
Ye s®Repair or replace the leaking component as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
4 At this time, the conditions required to set the DTC are not present.
Note: Use the Freeze Frame Data to help you duplicate the conditions that
set the DTC. Pay particular attention to the DTC set conditions, such as,
VSS, MAP, ECT, and Load.
Note: A thorough visual inspection of the Evap system hoses, tubes, and
connections may save time in your diagnosis. Look for any physical damage
or signs of wetness at connections. The strong smell of fuel vapors may aid
diagnosis also.
Note: Refer to any Technical Service Bulletins (TSB's) that may apply.
With the DRBIIItin System Tests, perform the LDP Monitor Test. This will force the
PCM to run the LDP Monitor. If the monitor fails, further diagnosis is required to
find faulty component. If the monitor passes, the condition is not present at this time.
Were any problems found?All
Ye s®Repair as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
138
DRIVEABILITY - GAS
P0442-EVAP LEAK MONITOR MEDIUM (.040) LEAK DETECTED Ð
Continued

TEST ACTION APPLICABILITY
8 Using a hand vacuum pump, apply 10 inches of vacuum to the Evap Purge Solenoid
vacuum source port on the component side.
Turn the ignition on.
Observe the vacuum gauge.
With the DRBIIIt, actuate the EVAP Purge Solenoid .
Does the vacuum drop when the solenoid is actuated?All
Ye s®Go To 9
No®Replace the Evap Purge Solenoid.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
9 If there are no possible causes remaining, view repair.
RepairAll
Repair
Replace and program the Powertrain Control Module in accor-
dance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
10WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
Perform a wiggle test of the Evap Purge Solenoid wiring while the circuit is actuated
with the DRBIIIt. Listen for the solenoid to quit actuating. Also watch for the Good
Trip Counter to change to 0.
Review the DRB Freeze Frame information. If possible, 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 broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
141
DRIVEABILITY - GAS
P0443-EVAP PURGE SOLENOID CIRCUIT ÐContinued