This article is intended to aid in diagnosing DTC’s P0171, P0174, P1130, P1131, P1150, P1151, P2195, or P2197 (system lean or lack of HEGO switches) when a vacuum leak is present. HEGO sensors, MAF sensors, and PCM replacements are not an effective repair when a vacuum leak is causing the above DTC’s.
ACTION
Perform the following inspections/repairs when the above codes are found in memory. Procedure provides instructions on how to make comparisons of the total fuel corrections (using scan tool or equivalent) at idle and high RPM’s to help determine if a vacuum leak is the root cause of the DTC’s.
FUEL TRIMS AT IDLE ARE PARTICULARLY SENSITIVE TO VACUUM LEAKS SINCE THE UN-METERED AIR “LEAKAGE FLOW” IS A HIGHER PERCENTAGE OF TOTAL AIRFLOW AT IDLE THAN AT PART THROTTLE. THE BAROMETRIC PRESSURE (BP) PID IS NOT RECOMMENDED TO VIEW WHEN DIAGNOSING A VACUUM LEAK. BP IS AN INFERRED PID CALCULATED DURING HIGHER ENGINE LOADS.
1. Perform preliminary inspection, retrieve and record DTC’s and Freeze Frame Data. DO NOT PERFORM KAM RESET OR OBDII RESET (CLEAR CODES) AT THIS TIME, ADAPTIVE FUEL TABLES MUST BE INTACT FOR THIS PROCEDURE.
Source
Friday, May 28, 2010
2000 Ford Contour Malfunction Indicator Lamp (MIL)
11:14 PM by onesecond
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Labels: air leakage, airflow, barometric pressure, bp, Ford, ford contour, indicator lamp, leaks, memory, p0171 p0174, p1130, pid, replacements, root cause, rpm, scan tool, sensors, switches, trims, vacuum leak
Labels: air leakage, airflow, barometric pressure, bp, Ford, ford contour, indicator lamp, leaks, memory, p0171 p0174, p1130, pid, replacements, root cause, rpm, scan tool, sensors, switches, trims, vacuum leak
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