Filed Under (Ford) by admin on 08-11-2010
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Some 2005-2006 Mustang vehicles may have a malfunction indicator lamp (MIL) on with diagnostic trouble code (DTC) P0456. This concern can be caused by an oversized orifice in the fuel pump. Suspect fuel pumps are in vehicles built before January 1, 2006. ACTION Follow the Service Procedure steps to correct the condition. SERVICE PROCEDURE Install the scan tool on the vehicle and monitor various inputs at different conditions to see if the vehicle needs to have the fuel pump replaced based on the calculation. Mustang Vapor Generation Test NOTE VEHICLE MUST MEET THE FOLLOWING CONDITIONS FOR THIS TEST: FLI% BETWEEN 15%-50% (INDICATES RIGHT SIDE FUEL TANK IS EMPTY) AND FUEL/VEHICLE TEMPS BETWEEN 70-80 ° (21- 27 ° F C). 1. Install IDS and perform Data logger function. 2. Select the following PIDs: FLI% (fuel level), FRP (fuel rail pressure), VMV # (Vapor Management Valve current), FTP voltage (Fuel tank pressure transducer output voltage), CVV # (Canister vent valve duty cycle). 3. Start engine – run for 5 minutes – turn off engine. 4. Access Jet Pump Module Connector 434 and verify sender resistance is at empty (16 ohms +/- 1 ohm). 5. Start engine, let idle for 30 seconds. 6. Check FRP to ensure fuel pressure is at 40 PSI +/- 2 PSI. 7. Close VMV to ensure a purge cycle does not take place during testing. 8. Record FTP voltage (should be at atmosphere – 2.61 volts). 9. Close CVV and monitor the elapse time. 10. Record FTP voltage after 30 seconds. 11. Open CVV and turn off engine.12. Record FTP voltage (should be the same – 2.61 volts). 13. Close CVV and monitor the elapse time. 14. Record FTP voltage after 30 seconds – open CVV. Calculate Dynamic vs. static FTP rise 15. Take reading from Step 10 (should be near 2.61) and subtract by the value in Step 8. 16. Take reading from Step 14 and subtract it by the reading in Step 12. 17. Take number from Step 16 and divide it by the number in Step 15. If the calculation is greater than a factor 3, replace the fuel pump. If the calculation is less than 3, continue with Workshop Manual diagnostics. 18. If the results from the dynamic test (KOER) are 3 times larger as the results of the static test (KOEO), the fuel pump is generating excess vapor.
