3.EXHAUST LEAK
Start the engine.
Inspect the exhaust for leaks between the engine and the 2/1 O2 Sensor.
Inspect the exhaust for leaks between the engine and the 2/2 O2 Sensor.
Are there any exhaust leaks?
Ye s>>
Repair or replace the leaking exhaust parts as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.ENGINE MECHANICAL
Check the exhaust for excessive smoke caused by an internal problem in the engine.
Is an engine mechanical condition present?
Ye s>>
Repair the engine mechanical condition as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.AGING O2 SENSOR
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 replaced without replacing the front O2 Sensor?
Ye s>>
Replace the 2/1 O2 Sensor as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
6.CATALYTIC CONVERTER
If there are no possible cause remaining, view repair.
Repair
Replace the Catalytic Converter.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
With engine temperature greater than 170° F, fuel control in closed loop, engine idling for 2 minutes, no low
fuel, MAP less than 15.7 inches mercury and barometric altitude less than 8,000 feet.
Set Condition:
After having passed the Leak Detection Pump (LDP) test, no air flow throughthe evaporative system is
detected by the EVAP monitor.
Possible Causes
EVAP PURGE HOSE (SOLENOID TO CANISTER)
EVAP PURGE HOSE (CANISTER TO FUEL TANK)
EVAP PURGE SOLENOID VACUUM SUPPLY
EVAP PURGE SOLENOID (LEAKS/STUCK OPEN)
EVAP PURGE SOLENOID
For the Engine circuit diagram (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CON-
TROL MODULE - SCHEMATIC - ELECTRICAL)
Diagnostic Test
1.VEHICLE HISTORY AND SERVICE BULLETIN INVESTIGATION
Ignition on, engine not running.
With a scan tool, read DTCs and record the related Freeze Frame data if any DTC(s) are present.
Whether or not any DTC(s) are present you will want to check the following items which may assist in repairing the
customer’s complaint successfully.
Check the vehicles repair history.
If the vehicle has a repair history that pertains to the customer’s currentcomplaint, review the repair.
Inspect the vehicle for any aftermarket accessories that may have been installed incorrectly.
Check for any service bulletin(s) related to the customer’s complaint or DTC(s).
If a service bulletin applies, follow the instructions per the service bulletin.
Choose the following scenario that best applies.
The service bulletin repaired the customer’s complaint.
Testing complete.
A DTC is present, no service bulletins apply, or the service bulletin didn’t repair the customer’s complaint.
Go To 2
2.GOOD TRIP EQUAL TO ZERO
Check for any related TSBs.
Ignition on, engine not running.
With the scan tool, read DTCs and record the related Freeze Frame data.
Is the Good Trip Counter displayed and equal to zero?
Ye s>>
Go To 3
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.VISUAL INSPECTION
Visually inspect the Evap canister. Look for any physical damage or any signs of fuel that has entered the canister.
Any signs of fuel may indicate a bad rollover valve.
Were any problems found?
Ye s>>
Repair or Replace as necessary.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.VISUAL INSPECTION OF EVAP PURGE HOSE (SOLENOID TO CANISTER)
Visually inspect the Evap purge hose that goes from the Purge Solenoid to the Evap Canister. Look for any physical
damage such as a pinched, plugged, ripped or dry rotted hose.
Were any problems found?
Ye s>>
Repair or replace hose as necessary.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.VISUAL INSPECTION OF EVAP PURGE HOSE (EVAP CANISTER TO FUEL TANK)
Visually inspect the Evap Purge hose that goes between the Evap canister and the fuel tank. Look for any physical
damage such as a pinched, plugged, ripped or dry rotted hose.
Were any problems found?
Ye s>>
Repair or replace hose as necessary.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
6.EVAP VACUUM SUPPLY HOSE INSPECTION
Carefully inspect the Evap Purge Solenoid vacuum supply hose for proper routing. Also check for a pinched or
plugged hose from the throttle body to the Purge Solenoid.
Inspect the vacuum nipple at the throttle body for any damage or plugging.
Make sure vacuum fitting at the purge solenoid is not over installed.
Is the vacuum supply hose and throttle body vacuum nipple free from defects?
Ye s>>
Go To 7
No>>
Repair the vacuum supply hose/tube as necessary.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
7.EVAP PURGE SOLENOID LEAKS
NOTE: 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 purge
solenoid if contamination is found
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. (com-
ponent side)
Does the Evap Purge Solenoid hold vacuum?
Ye s>>
Go To 8
No>>
Replace the Evap Purge Solenoid and the Evap Canister and clean out Evap lines as necessary.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
8.EVAP PURGE SOLENOID
Using a hand vacuum pump, apply 10 inches of vacuum to the Evap Purge Solenoid vacuum source port. (com-
ponent side)
Ignition on, engine not running.
With the scan tool, actuate the EVAP Purge Solenoid and observe the vacuum gauge.
Does the vacuum drop when the solenoid is actuated?
Ye s>>
Refer to the INTERMITTENT CONDTION Symptom (Diagnostic Procedure).
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace the Evap Purge Solenoid.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
Immediately after a cold start, with battery/ambient temperature between 40° F and 90° F and coolant tem-
perature within 10° F of battery/ambient.
Set Condition:
If there is a leak larger than 0.040
and smaller than 0.080in the evaporative system.
Possible Causes
EVAP PURGE SYSTEM LEAK
GAS CAP
EVAP PURGE SOLENOID
LEAK DETECTION PUMP
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.VEHICLE HISTORY AND SERVICE BULLETIN INVESTIGATION
Ignition on, engine not running.
With a scan tool, read DTCs and record the related Freeze Frame data if any DTC(s) are present.
Whether or not any DTC(s) are present you will want to check the following items which may assist in repairing the
customer’s complaint successfully.
Check the vehicles repair history.
If the vehicle has a repair history that pertains to the customer’s currentcomplaint, review the repair.
Inspect the vehicle for any aftermarket accessories that may have been installed incorrectly.
Check for any service bulletin(s) related to the customer’s complaint or DTC(s).
If a service bulletin applies, follow the instructions per the service bulletin.
Choose the following scenario that best applies.
The service bulletin repaired the customer’s complaint.
Testing complete.
A DTC is present, no service bulletins apply, or the service bulletin didn’t repair the customer’s complaint.
Go To 2
2.ACTIVE DTC
NOTE: Since a hot vehicle can conceal a leak, it is best to perform this test at room temperature.
NOTE: A loose gas cap could have caused this DTC to set. Make sure gas cap is tight and in good condi-
tion. Make sure the gas cap meets OEM specifications.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 3
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.VISUAL AND PHYSICAL INSPECTION
Perform a visual and physical inspection of the entire Evaporative Emission system.
Check for the follow conditions:
- Holes or cracks
- Loose seal points
- Evidence of damaged components
- Incorrect routing of hoses and tubes
- Fuel Cap gasket seal
Were any of the above conditions found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.VERIFY EVAPORATIVE EMISSION LEAK
To continue testing you will need Miller Tool #8404A Evaporative EmissionLeak Detector (EELD).
WARNING: Keep lit cigarettes, sparks, flames, and other ignition sourcesaway from the test area to prevent
the ignition of explosive gases. Keep the test area well ventilated.
NOTE: The fuel tank should have between 20% and 80% of fuel tank capacity to properly test the Evap
system.
Connect the red power lead of the EELD to the battery positive terminal and the black ground lead to battery neg-
ative terminal.
Block the vent hose of the canister if using the service port.
Connect shop air to the EELD.
Set the smoke/air control switch to AIR.
Insert the tester’s AIR supply tip (clear hose) into the appropriate calibration orifice on the tester’s control panel
(based on DTC leak size).
Press the remote smoke/air start button.
Position the red flag on the air flow meter so it is aligned with the indicatorball.
When the calibration is complete, release the remote button. The EELD flowmeter is now calibrated in liters per
minute to the size leak indicated by the DTC set in the PCM.
Install the service port adapter #8404-14 on the vehicle’s service port and block the vent hose of the EVAP Canister
(if equipped) or install the #8404-ADP service adaptor into the filter line.
Connect the Air supply hose from the EELD to the service port (if equipped) or to the #8404-ADP adapter.
Press the remote button to activate AIR flow.
NOTE: Larger volume fuel tanks, lower fuel levels or if the vehicle is equipped with a Flow Management
Valve may indicate high flow and will require 4 to 5 minutes to fill.
Compare the flow meter indicator ball reading to the red flag.
ABOVE the red flag indicates a leak present.
BELOW the red flag indicates a sealed system.
Is the indicator ball above the red flag?
Ye s>>
Go To 5
No>>
Refer to the Freeze Frame data recorded in Step 1. If the data indicates thatthe vehicle was in motion
when the DTC was set, verify that all hoses are properly connected. Test Complete.
6 Fuel Tank to Canister Vapor Line connection.
7 Evap Purge connection.
ZONE 3
1 Evap Purge Vacuum Line.
2 Connection to Chassis Line.
3 Connection to Canister.
4 Chassis Purge Line.
5 Evap Purge Vacuum Line.
6 Connection to Evap Purge Harness.
7 Chassis Evap Purge Line connection to Engine Vacuum.
8EvapPurgeValve.
9ServicePort.
Wasaleakfound?
Ye s>>
Go To 6
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 7
6.LEAK AT GAS CAP
Remove the SMOKE supply tip (black hose) from the service port (if equipped) or to the #8404–ADP adapter.
Install gas cap adapter, Miller Tool #8382 (1/4 turn cap) or #6922 (screw cap) and #8399* (secondary seal depres-
sor) and repeat test 5.
Was a leak found at the gas cap adapter?
Ye s>>
Replace the Fuel Filler tube assembly.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace the gas cap.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
7.LEAK DETECTION PUMP
Apply an external vacuum to the LDP.
Using a scan tool, close the LDP seal to atmosphere.
Inject smoke into the Evap system using the EELD.
Examine the LDP filter port for smoke.
Is smoke visible from the LDP?
Ye s>>
Replace the Leak Detection Pump.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 8
8.EVAP PURGE SOLENOID OPERATION
To continue testing you will need Miller Tool #8404 Evaporative Emission Leak Detector (EELD).
Connect the red power lead of the EELD to the battery positive terminal and the black ground lead to the battery
negative ternal.
Disconnect the vacuum hoses at the Evap Purge Solenoid.
Connect the SMOKE supply tip (black hose) to the service port (if equipped)or to the #8404-ADP adapter.
Set the smoke/air control switch to SMOKE.
Press the remote smoke/air start button.
NOTE: Below is an optional method of checking the purge valve for leaks if the EELD is unavailable.
Turn the ignition off.
Disconnect the vacuum hoses at the Evap Purge Solenoid.
Using a hand vacuum pump, apply 10 in Hg to the
CANof the EVAP Purge Solenoid.
With the scan tool, actuate the Evap Purge Solenoid.
NOTE: If the Evap Purge Solenoid does not hold a vacuum, it will need to be repalced..
Is smoke visible from the Evap Purge Solenoid?
Ye s>>
Replace the Evap Purge Solenoid.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .