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Adaptive Fuel Control

NOTE: The following test procedures are for DTCs P0171, P0172, P0174 and P0175.

Fig 1: Adaptive Fuel Control Detection Condition Possible Cause

G03723684

Courtesy of MAZDA MOTORS CORP.

ADAPTIVE FUEL CONTROL INSPECTION/ACTION CHART

STEP	INSPECTION		ACTION
1	Was PCM Quick Test performed?	Yes	If Misfire DTC (P0300-P0306) is present or drive ability concern is present, see DIAGNOSTIC TROUBLE CODE NUMBERS . If any other DTC is present, see DIAGNOSTIC TROUBLE CODE NUMBERS . Otherwise, go to next step.
1	Was PCM Quick Test performed?	No	Perform PCM Quick Test. See PCM QUICK TEST .
2	CHECK CONDITIONS RELATED TO MAF/IAT SENSOR NOTE: Most weather service reports are a local barometric pressure that has been corrected to sea level. However, the BARO PID reports the actual barometric pressure for the altitude the vehicle is being diagnosed in. Local weather conditions (high or low pressure areas) will change the local barometric pressure by several inches of mercury. Key ON, Engine Running (KOER). Access the PCM-LONGFT1, PCM-LONGFT2, PCM-MAF V, and PCM-BARO PIDs. Check that the BARO PID is approximately the same as the barometric pressure reading for the location, day, and altitude in which the vehicle is being worked on. BARO PID values in Keep Alive Memory require updating at high throttle openings. If vehicle is driven down from higher altitudes for diagnosing, complete three or four heavy accelerations at greater than half-throttle to allow BARO PID to update. BARO PID must be within +/- 6 Hz. (+/- 2 in. Hg.) of the altitude value in Barometric Pressure Reference Chart. See MASS AIR FLOW (MAF) SENSOR . Make BARO PID comparisons to Barometric Pressure Reference Chart or daily airport barometric pressure reports, if available. Check that LONGFT1 and LONGFT2 PIDs for all injector banks at idle are not more negative than -12%. Check that MAF V PID at idle and neutral is not greater than 30% of the normal MAF V listed, or 1.1 volts. Are two of the three checks OK?	Yes	Go to step 4.
2		No	Key OFF. Go to next step.
3	ISOLATE MAF/IAT SENSOR FROM LEAN DRIVEABILITY OCCURRENCE Due to increasingly stringent emission/OBD2 requirements, a fuel system DTC on some vehicles will be generated without a noticeable driveability concern with or without the MAF sensor disconnected. Under these conditions, if BARO_V, LONGFT1, LONGFT2, and MAF PIDs indicate a MAF sensor concern, install a new MAF sensor. Disconnect MAF/IAT sensor connector. Key ON, Engine Running (KOER). Is the driveability symptom gone?	Yes	Replace the MAF/IAT sensor. See MASS AIR FLOW (MAF) SENSOR -- 2.3L . Go to step 7.
3		No	Go to next step.
4	PERFORM KOER SELF-TEST Connect MAF/IAT sensor. Disconnect fuel vapor hose from the intake manifold and plug the fitting at the intake manifold. Start engine and run at 2,000 RPM for 5 minutes, then return to idle. Key ON, Engine Running (KOER). Perform KOER Self-Test. Check Self-Test DTCs. Are DTCs P0040, P1128, P0041, P1129, P1127, or P0402 present?	Yes	Key OFF. Disregard the current DTCs at this time. See DIAGNOSTIC TROUBLE CODE NUMBERS to diagnose other DTCs.
4		No	Key OFF. Go to next step.
5	DETERMINE DTC BEING DIAGNOSED Check Self-Test DTCs. Are DTCs P1131, P2195, P1151, or P2197 present?	Yes	GO to UPSTREAM HEATED OXYGEN SENSOR (HO2S) NOT SWITCHING .
5		No	Go to next step.
6	DETERMINE DTC BEING DIAGNOSED Check Self-Test DTCs. Are DTCs P1132, P2196, P1152, or P2198 present?	Yes	GO to UPSTREAM HEATED OXYGEN SENSOR (HO2S) NOT SWITCHING .
6		No	Reconnect fuel vapor line. Unable to identify fault at this time.
7	VERIFY TROUBLESHOOTING OF DTCs COMPLETED Perform PCM Quick Test. See PCM QUICK TEST . Is any DTC present?	Yes	See DIAGNOSTIC TROUBLE CODE NUMBERS .
7		No	Troubleshooting complete.