DTC P1486: EVAP LEAK MONITOR PINCHED HOSE FOUND
EVAP leak monitor is monitored after cold start with ambient temperature of 40-90 F (4-32 C) and coolant temperature within 10 F of ambient temperature. If PCM detects a pinched hose, DTC will not set until EVAP monitor performs system test. If system test fails, DTC will set. DTC will set in Powertrain Control Module (PCM) memory when EVAP monitor senses no airflow through EVAP system. Possible causes for DTC to set are: blocked fuel tank-to-EVAP canister hose, blocked Leak Detection Pump (LDP) hose, pinched EVAP purge solenoid-to-EVAP canister hose, blocked LDP or blocked EVAP canister.
Monitored & Set Conditions
Turn ignition on. Using scan tool, read DTCs. If Good Trip counter is displayed for DTC P1486 and displayed count is "0", go to next step. If Good Trip counter is not displayed for DTC P1486 or displayed count is not "0"
CAUTION:When performing test procedures, keep lighted cigarettes, sparks, flames and other ignition sources away from test area.
To continue testing you will need Miller Evaporative Emission Leak Detector (8404). The fuel tank should have between 20% and 80% of fuel tank capacity to properly test the EVAP system. Disconnect the vacuum supply hose at the Leak Detection Pump. Connect and apply a continuous vacuum supply (i.E. 20 in. Hg) to the Leak Detection Pump. A vacuum pump such as an A/C recovery unit works well. Using the DRBIII(R), select Engine/System Tests and actuate the Leak Detect Pump Test (Option 3/Hold PSI). This energizes the LDP solenoid and allows the constant vacuum source to apply vacuum to the LDP pump diaphragm. This lifts the diaphragm up and seals the atmospheric canister vent valve at the bottom of the Leak Detection Pump. Connect the Red power lead of Miller Evaporative Emission Leak Detector to the battery positive terminal and the Black ground lead to battery negative terminal. Connect shop air to the Evaporative Emission Leak Detector. 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 indicator ball. When the calibration is complete, release the remote button. The Evaporative Emission Leak Detector has now calibrated the flow meter 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. Connect the Air supply hose from the Evaporative Emission Leak Detector to the service port. Press the remote button to activate AIR flow. Larger volume fuel tanks, and/or those with less fuel, may require 4 to 5 minutes to fill. The flow meter gauge on the Evaporative Emission Leak Detector will read zero LPM when the EVAP system is completely pressurized. Disconnect the hose at the
EVAP Canister that goes to the Fuel Tank. Did the pressure drop when the hose was disconnected. If yes, go to next step. If no, repair the obstruction in the EVAP system between the EVAP Canister and the Fuel Tank. Reconnect all previously disconnected hose(s). Re-pressurize the EVAP System. Using Evaporative Emission Leak Detector, hold down the Remote Smoke/Air Start Button and monitor the gauge. The flow meter gauge on the Evaporative Emission Leak Detector reads 0 LPM the EVAP system completely pressurized. Disconnect the LDP pressure hose at the EVAP canister. The LDP pressure hose is the hose that connects the EVAP canister to the leak detection pump. Did the pressure drop when the hose was disconnected? If yes, go to next step. If no, replace the EVAP canister. Reconnect all previously disconnected hose(s). Re-pressurize the EVAP System. On Evaporative Emission Leak Detector, set the Pressure/Hold switch to Open and set the Vent switch to Closed. Turn the pump timer On and watch the gauge. The flow meter gauge on the Evaporative Emission Leak Detector reads 0 LPM the EVAP system completely pressurized. Disconnect the EVAP hoses at the Purge Solenoid. Did the pressure drop when the hose was disconnected? If yes, go to next step. If no, repair or replace hose/tube as necessary. Disconnect and remove the LDP pressure hose. The LDP pressure hose is the hose that connects the EVAP Canister to the Leak Detection Pump. Inspect the LDP pressure hose for any obstructions or physical damage. Is the LDP pressure hose free from defects? If yes, replace the Leak Detection Pump. If no, repair/replace hose as necessary. At this time, the conditions required to set the DTC are not present. 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. 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. Refer to any Technical Service Bulletins (TSB) that may apply. With the DRBIII(R) in 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? If yes, repair as necessary. If no, test is complete.
Thursday, September 17th, 2009 AT 6:09 AM