DC25 DTC P0171, P0172, P0174, P0175, P1131, P1132, P1151, P1152, P1130, P1150, P2195, P2196, P2197, P2198: (OR LEAN DRIVEABILITY CONCERNS) CHECK CONDITIONS RELATED TO THE MAF SENSOR
CHECK the air inlet system (air cleaner, housing, ductwork) for obstructions or blockage.
CHECK for broken/loose air outlet tube clamps (throttle body and air cleaner assembly ends), cracks/holes in the air outlet tube, and worn gaskets between the MAF sensor and the air cleaner assembly. Verify the MAF sensor is connected.
Were any problems found?
Yes No
Repair as required and reset KAM. GO to DC26 .
DC26 DTC P0171, P0172, P0174, P0175, P1131, P1132, P1151, P1152, P1130, P1150, P2195, P2196, P2197, P2198: (OR LEAN DRIVEABILITY CONCERNS) CHECK CONDITIONS RELATED TO THE MAF SENSOR
Note: Most weather 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 where the vehicle is being diagnosed. Local weather conditions (high or low pressure areas) will change the local barometric pressure by several inches of mercury.
Note: The BARO PID values in Keep Alive Memory require updating at high throttle openings. If the vehicle is driven down from higher altitudes for diagnosing, carry out 3 or 4 heavy accelerations at greater than half-throttle to allow the BARO PID to update. Make BARO PID comparisons to the Barometric Pressure Reference Chart or hourly airport barometric pressure or altimeter reports, if available. The BARO PID must be within +/- 6 Hz. (+/- 2 in Hg.) of the altitude value in Barometric Pressure Reference Chart (at the beginning of this pinpoint test).
Note: A MAF V PID value of less than 0.6 volt may indicate an incorrectly installed air cleaner or a leak in the air inlet system.
Key ON, engine running.
Allow the engine to stabilize at the correct operating temperature.
Access the PCM and monitor the LONGFT1, LONGFT2, MAF V and BARO PIDs.
Carry out the following diagnostic checks:
Check that the BARO PID is approximately the same as the barometric pressure reading for the location, day, and altitude where the vehicle is being diagnosed.
Check that the MAF V PID at idle and neutral is not greater than 30% of the normal MAF V listed in Section 6 , Reference Values (or not greater than 1.3 volts).
Are the PID values within the expected ranges?
Yes No
GO to DC28 . Key in OFF position.
GO to DC27 .
DC27 CHECK TO ISOLATE MAF SENSOR FROM LEAN DRIVEABILITY OCCURRENCE
Due to increasingly stringent emission/OBD2 requirements, a fuel system DTC on some vehicles can be generated without a noticeable driveability concern with or without the MAF sensor disconnected. Under these conditions, if the BARO_V, LONGFT1, LONGFT2 and MAF PIDs indicate a MAF sensor concern, install a new MAF sensor.
MAF/IAT Sensor connector disconnected.
Key ON, engine running.
Drive the vehicle on the road.
Is the lean driveability symptom (lack of power, spark knock/detonation, buck/jerk or hesitation/surge on acceleration) gone?
Yes No
INSTALL a new MAF/IAT sensor.
Reset KAM. GO to DC28 .
DC28 VERIFY THE DTC
Are any of the following DTCs present:
P0171, P0172, P0174, P0175, P1130, P1131, P1132, P1150, P1151, P1152, P2195, P2196, P2197 or P2198?
Yes No
GO to DC29 . The concern is elsewhere. RETURN to Section 3 , Symptom Charts for further direction.
DC29 VERIFY THE TYPE OF VEHICLE
Is this a natural gas vehicle?
Yes No
For DTCs P0171, P0172, P0174, P0175, P1130 and P1150
GO to HA13 .
For DTCs P1131, P1151, P2195 and P2197
GO to HA30 .
For DTCs P1132, P1152, P2196 and P2198
GO to HA41 . Unable to duplicate or identify the fault at this time.
GO to Z1 .