TEST ACTION APPLICABILITY
3 Disconnect the vacuum hose from the EGR Valve.
Start the engine and allow it to idle.
Does the engine run rough or stall at idle?All
Ye s®Remove the EGR Valve and inspect the valve for an obstruction
that would keep the valve open. If OK, replace the EGR Valve.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 4
4 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 5
5 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.
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®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.
6 Turn the ignition off.
Disconnect the EGR Solenoid vacuum supply at the EGR Solenoid.
Connect a vacuum gauge to the EGR Solenoid vacuum supply.
Start the engine.
Observe the vacuum gauge.
Does the vacuum gauge read above 109?All
Ye s®Go To 7
No®Repair the EGR Solenoid vacuum supply.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
7 Disconnect the vacuum hose from the EGR Valve.
Connect a Vacuum Pump to the EGR Valve.
Using the Vacuum Pump, apply vacuum to the EGR Valve.
Does the engine run rough or stall at idle?All
Ye s®Go To 8
No®Remove the EGR Valve and inspect the valve for an obstruction
that would keep the valve form opening. If OK, replace the EGR
Valve.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
125
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
Symptom:
P0403 - EGR SOLENOID CIRCUIT
When Monitored and Set Condition:
P0403 - EGR SOLENOID CIRCUIT
When Monitored: Engine running. Battery voltage greater than 10 volts.
Set Condition: The EGR solenoid control circuit is not in the expected state when
requested to operate by the PCM.
POSSIBLE CAUSES
INTERMITTENT CONDITION
EGR SOLENOID
FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN
EGR SOLENOID CONTROL CKT SHORTED TO VOLTAGE
EGR SOLENOID CONTROL CKT SHORT TO GND
EGR SOLENOID CONTROL CKT OPEN
PCM
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip displayed and equal to zero?All
Ye s®Go To 2
No®Go To 8
2 Turn the ignition off.
Disconnect the EGR Solenoid harness connector.
Turn the ignition on.
Turn all accessories off.
Using a 12 volt Test Light connected to the Fused Ignition Switch Output circuit,
probe the EGR Solenoid Control circuit.
With the DRB, actuate the EGR solenoid.
Does the 12 volt test light flash on and off?All
Ye s®Inspect the EGR Valve Back Pressure hose and tube for obstruc-
tions or damage. If OK, replace the EGR Solenoid.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 3
128
DRIVEABILITY - GAS
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
Symptom:
P0420-1/1 CATALYTIC CONVERTER EFFICIENCY
When Monitored and Set Condition:
P0420-1/1 CATALYTIC CONVERTER EFFICIENCY
When Monitored: After engine warm up to 70ÉC (158ÉF), 180 seconds of open throttle
operation, at a speed greater than 18 mph and less than 55 mph, with the engine at
1200-1700 rpm and MAP vacuum between 15.0 and 21.0 inches of mercury (Hg).
Set Condition: As catalyst efficiency deteriorates, the switch rate of the downstream O2
sensor approaches that of the upstream O2 sensor. If at any point during the test the
switch ratio reaches a predetermined value a counter is incremented by one.
POSSIBLE CAUSES
INTERMITTENT CONDITION
VISUALLY INSPECT CATALYTIC CONVERTER
EXHAUST LEAK
ENGINE MECHANICAL CONDITION
AGING O2 SENSOR
CATALYTIC CONVERTER
TEST ACTION APPLICABILITY
1NOTE: If a O2 Sensor DTC(s) set along with the Catalytic Converter
Efficiency DTC diagnose the O2 Sensor DTC(s) before continuing.
NOTE: Check for contaminates that may have damaged the O2 Sensor and
Catalytic Converter: contaminated fuel, unapproved silicone, oil and cool-
ant, repair necessary.
Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip displayed and equal to zero?All
Ye s®Go To 2
No®Go To 7
2 Inspect the Catalytic Converter for the following damage.
Damage Catalytic Converter, dent and holes.
Severe discoloration caused by overheating the Catalytic Converter.
Catalytic Converter broke internally.
Leaking Catalytic Converter.
Were any problems found?All
Ye s®Replace the Catalytic Converter. Repair the condition that may
have caused the failure.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 3
131
DRIVEABILITY - GAS
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
Symptom:
P0441-EVAP PURGE FLOW MONITOR
When Monitored and Set Condition:
P0441-EVAP PURGE FLOW MONITOR
When Monitored: With engine temperature greater than 71ÉC (160ÉF), fuel control in
closed loop, engine idling for 200 seconds, no low fuel, MAP less than 23.6 inches mercury
and barometric altitude less than 8,000 feet.
Set Condition: After having passed the Leak Detection Pump (LDP) test, no air flow
through the evaporative system is detected by the evap monitor.
POSSIBLE CAUSES
INTERMITTENT CONDITION
EVAP PURGE SOLENOID LEAKS/STUCK OPEN
EVAP PURGE SOLENOID STUCK CLOSED
EVAP PURGE SOLENOID VACUUM SUPPLY
EVAP PURGE HOSE SOLENOID TO CANISTER
EVAP PURGE HOSE CANISTER TO FUEL TANK
EVAP CANISTER
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip Counter displayed and equal to zero?All
Ye s®Go To 2
No®Go To 8
2NOTE: After disconnecting the Evap Purge Solenoid vacuum connections,
inspect the lines and solenoid for any signs of contamination from the EVAP
Canister. This may indicate a faulty rollover valve. Replace/repair as
necessary.
Turn the ignition off.
Disconnect the vacuum hoses at the Evap Purge Solenoid.
Using a hand vacuum pump, apply 10 inches of vacuum to the Evap Purge Solenoid
vacuum source port on the component side.
Does the Evap Purge Solenoid hold vacuum?All
Ye s®Go To 3
No®Replace the Evap Purge Solenoid.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
133
DRIVEABILITY - GAS
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