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Evaporative Emission (EVAP) Monitor And System

DTC P1450 DETECTION CONDITION AND POSSIBLE CAUSE

DTC P1450 EVAP CANISTER PURGE VALVE MALFUNCTION
DETECTION CONDITION 
  • P1450 indicates the Self Test has detected that the EVAP System is unable to bleed up fuel tank vacuum.
POSSIBLE CAUSE 
  • Blockages or kinks in EVAP canister tube or EVAP canister purge outlet tube (between fuel tank, EVAP canister purge valve and EVAP canister.
  • Fuel filler cap stuck closed (no vacuum relief).
  • Contaminated fuel vapor elbow on EVAP canister.
  • Restricted EVAP canister.
  • CV solenoid stuck open (partially or fully)
  • Plugged CV solenoid filter.
  • EVAP canister purge valve stuck open.
  • VREF circuit open (harness near FTP sensor, FTP sensor or PCM).
  • Damaged FTP sensor.
HINT 
  • Refer to EVAP RUNNING LOSS SYSTEM MONITOR

    EVAP Canister Purge Valve Description 

  • Normally closed valve.
  • Controls the flow of vapors (purging) from the EVAP canister to the intake manifold during various engine operating modes.
DTC P1450 INSPECTION

STEP INSPECTION ACTION
1
  • Was PCM Quick Test performed? 
 Yes Go to next step.
No Perform PCM Quick Test.
2 DTC P1450: CHECK FOR VISUAL CAUSES OF EXCESSIVE FUEL TANK VACUUM
  • Check for kinks or bends in the fuel vapor hoses and tubes.
  • Visually inspect EVAP canister inlet port, canister vent solenoid, EVAP dust separator or outlet hose for contamination or foreign material.
  • Is a concern evident? 
 Yes Remove any contamination or foreign material around fuel vapor hoses and tubes. Repair the hoses, tubes or components as necessary. Go to step 7.
No Go to next step.
3 PERFORM EVAP LEAK TEST
  • Connect EVAP Leak Tester to the fuel filler pipe.
  • Close the CV solenoid by accessing the Output Test Mode.
  • Pressurize the EVAP system to 3.48 kPa (14 in-H2 O).
  • Does the pressure reach 3.48 kPa (14 in-H 2  O)? 
 Yes Go to next step.
No Check to see if the EVAP canister purge valve is stuck open. Replace if necessary. Go to step 7.
4 CHECK FOR CANISTER VENT SOLENOID STUCK CLOSED
  • Press STOP (#4) to open the CV solenoid.
  • Does the pressure drop immediately? 
 Yes Go to next step.
No Go to PINPOINT TEST 2: HISS WHEN OPENING FUEL CAP .
See PINPOINT TEST 2: HISS WHEN OPENING FUEL CAP .
5 CHECK FOR FUEL TANK PRESSURE SENSOR PID WITHOUT PRESSURE APPLIED
  • Disconnect the EVAP canister outlet tube at the EVAP canister.
  • Key ON, Engine OFF (KOEO).
  • Access FTP V PID using NGS Tester and record the reading.
  • Is the reading between 2.40 to 2.80 V? 
 Yes Go to next step.
No Replace fuel tank pressure sensor.
See BRAKE PEDAL POSITION (BPP) SWITCH MALFUNCTION  .
Go to step 6.
6 EVAP SYSTEM LEAK TEST Yes Go to step 8.
No Leakage still exists. Locate leak point and repair. Repeat this step.
7 DRIVE CYCLE
  • Make sure to reconnect all disconnected connectors.
  • Clear DTCs from PCM memory using NGS tester generic OBD-II function.
  • Perform EVAP System Monitor Drive Cycle.

    See DRIVE CYCLES .

  • Retrieve pending code.
  • Is same DTC present? 
 Yes Replace PCM. See COMPUTERIZED ENGINE CONTROLS .
Go to next step.
No Go to next step.
8 VERIFY REPAIR
  • Perform PCM Quick Test.
  • Is any DTC present? 
 Yes Go to applicable DTC inspection.
No Troubleshooting complete.
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