Ford Mustang (1999-2004) Service Manual: Inspection and Verification

1. Verify the customer concern is with the evaporative emission (EVAP) system.

2. Visually inspect for the following obvious signs of mechanical damage.

Visual Inspection Chart

Mechanical

  • Fuel filler cap

  • EVAP test port

  • EVAP canister or canister vent solenoid

  • EVAP lines or hoses

  • Vacuum lines or hoses

3. If the concern remains after the inspection, connect the scan tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the scan tool menu. If the scan tool does not communicate with the vehicle:

  • check that the program card is correctly installed.
  • check the connections to the vehicle.
  • check the ignition switch position.

4. If the scan tool still does not communicate with the vehicle, refer to the scan tool manual.

5. Carry out the DATA LINK DIAGNOSTICS test. If the scan tool responds with:

  • CKT914, CKT915 or CKT70 = ALL ECUS NO RESP/NOT EQUIP, refer to Section.
  • NO RESP/NOT EQUIP for PCM, refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.
  • SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out the PCM KOEO self-test.

6. If the DTCs retrieved are related to the concern, go to the PCM Diagnostic Trouble Code (DTC) Index to continue diagnostics.

7. If the concern remains after the inspection, determine the symptom. GO to Symptom Chart .

PCM Diagnostics Trouble Code (DTC) Index

DTC Description Source Action
P0442 Small leak detected in EVAP system (As small as 1.02 mm [0.040 inch]) PCM Go To Pinpoint Test A .
P0455 Major leak or no flow detected PCM Go To Pinpoint Test B .
P0457 Check for missing or leaking fuel filter cap PCM Go To Pinpoint Test A .
P1443 Very small or no purge flow detected PCM Go To Pinpoint Test B .
P1450 Excessive vacuum detected in the fuel tank PCM Go To Pinpoint Test C .
- Any other PCM DTC PCM REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.

Symptom Chart

Condition Possible Sources Action
  • Hissing sound when removing fuel cap
  • Canister vent solenoid.
  • Evaporative emissions canister.
  • Fuel vapor control valve tube assembly.
  • EVAP canister tube.
  • EVAP canister purge outlet tube.
  • Go To Pinpoint Test D .
  • Excessive fuel odor
  • Canister vent solenoid.
  • Evaporative emissions canister.
  • Fuel vapor control valve tube assembly.
  • Evaporative emissions test port.
  • EVAP canister purge outlet tube.
  • Go To Pinpoint Test E .
  • Unable to refuel vehicle
  • Fuel filler pipe.
  • Canister vent solenoid.
  • Fuel vapor control valve tube assembly.
  • Go To Pinpoint Test D .
    Principles of Operation
    Evaporative Emission (EVAP) Canister Purge Valve The EVAP canister purge valve is controlled by the powertrain control module (PCM). The EVAP canister purge valve controls the flow of fuel vapors ...

    Pinpoint Tests
    NOTE: Reinstall or install new evaporative emission hose clamps removed or damaged during testing procedures. PINPOINT TEST A: DTC P0442 SMALL LEAK IN EVAP SYSTEM Test Step Result / Action to ...

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