LEMON Manuals: Even more car manuals for everyone
Home >> Jeep >> 2001 >> Cherokee Classic, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1486: EVAP Leak Monitor Pinched Hose Found >> Testing

DTC P1486: EVAP Leak Monitor Pinched Hose Found: Testing

NOTE: Replacing PCM will not correct this problem.
  1. 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", go to step  7 .
    2. CAUTION: When performing test procedures, keep lighted cigarettes, sparks, flames and other ignition sources away from test area.
  2. To test EVAP system properly, fuel tank should have 20-80 percent of fuel capacity. Miller Evaporative System Testing Kit (6872A) and Gas Cap Adapter (8382) are used to perform evaporative system pressure test. Connect scan tool to Data Link Connector (DLC). Connect EVAP system testing kit positive lead to positive battery terminal and negative lead to negative battery terminal. Using EVAP system testing kit, and instructions printed on EVAP system testing kit cover, perform EVAP system pressure pump self-test. Remove gas cap and install gas cap adapter to fuel tank. Install gas cap to gas cap adapter. Connect pressure supply hose from evaporative system testing kit to fitting on gas cap adapter. Disconnect vacuum supply hose at Leak Detection Pump (LDP). LDP is located at right rear of engine compartment. See Figure . Apply a continuous vacuum supply of about 20 in. Hg to vacuum supply nipple on LDP. An A/C recovery unit works well for supplying a continuous vacuum supply. Turn ignition on. Using scan tool, select ENGINE SYSTEM TESTS, then LEAK DETECTION PUMP TEST. Read instructions on scan tool and then press ENTER. Select #3 HOLD PSI. Set EVAP system testing kit PRESSURE/HOLD valve to OPEN and set VENT valve to CLOSED. While monitoring EVAP system testing kit pressure gauge, turn EVAP system testing kit pump timer on. When gauge reaches 14 in. H2O, set PRESSURE/HOLD valve to CLOSED. Turn pump timer off. Disconnect fuel tank-to-EVAP canister purge hose (at EVAP canister) while monitoring gauge on evaporative system testing kit. If pressure decreases when purge hose is disconnected, go to next step. If pressure does not decrease when purge hose is disconnected, repair obstruction in EVAP system between EVAP canister and fuel tank.
  3. Reconnect purge hose to EVAP canister. With engine still running and pump timer turned on, allow evaporative system to repressurize. Ensure PRESSURE/HOLD valve on evaporative system testing kit is set to OPEN and VENT valve is set to CLOSED. When gauge reaches 14 in. H2O, set PRESSURE/HOLD valve to CLOSED. Turn pump timer off. Disconnect LDP pressure hose (at EVAP canister) that connects EVAP canister to LDP while monitoring gauge on evaporative system testing kit. If pressure decreases when hose is disconnected, go to next step. If pressure does not decrease when hose is disconnected, replace EVAP canister.
  4. Reconnect LDP pressure hose. With engine still running and pump timer turned on, allow evaporative system testing kit to repressurize. Ensure PRESSURE/HOLD valve on evaporative system testing kit is set to OPEN and VENT valve is set to CLOSED. When gauge reaches 14 in. H2O, set PRESSURE/HOLD valve to CLOSED. Turn pump timer off. Disconnect EVAP purge solenoid hoses while monitoring gauge on evaporative system testing kit. EVAP purge solenoid is mounted on a bracket at right rear of engine compartment. See Figure . If pressure does not decrease when hoses are disconnected from EVAP canister, repair or replace hose/tubes to EVAP purge solenoid as necessary. If pressure decreases when vacuum hoses are disconnected from EVAP canister, go to next step.
  5. Inspect pressure hose between EVAP canister and LDP. If pressure hose is okay and is not restricted, go to next step. If pressure hose is defective or restricted, replace pressure hose.
  6. At this time, LDP is assumed to be defective. Replace LDP.
  7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Using scan tool, review FREEZE FRAME data. Attempt to duplicate condition that caused DTC to set. Thoroughly perform a visual inspection of EVAP system hoses, tubes and connections. Look for any physical damage or signs of wetness at connections. Visually inspect related connectors and wiring harness for damage. Check for any related technical service bulletins that may apply. Turn ignition on. Using scan tool in SYSTEM TESTS, perform LDP monitor test. This will force the PCM to run LDP monitor. If monitor fails, further diagnosis is required to find faulty component. Go to step  2 . If monitor passes, no problem is indicated at this time. Test is complete.
scientia non olet · About LEMON Manuals