Mechanics

MASS AIR FLOW SENSOR

2000 Ford Windstar

Engine Performance problem
2000 Ford Windstar 6 cyl Front Wheel Drive 130000 miles

had mass air flow sensor change 2-3 months later check engine comes back for same thing started shcool for automotive want to know how to check and repair if systems says low or high input indicated look at wiring diagrams how do I check and repair
Avatar
Samuel pirella
April 11, 2010.




TEST DC: MASS AIRFLOW SENSOR
NOTE: After each service or repair procedure has been completed, reconnect all components. Clear DTCs and repeat QUICK TEST procedures to ensure all EEC-V systems are working properly and DTCs are no longer present.

Diagnostic Aids
Perform this test when directed by QUICK TEST. This test is intended to diagnose the following.
MAF Sensor
Wiring Harness Circuits (VPWR, PWR GND, MAF SIG & MAF RTN)
Powertrain Control Module (PCM)
To prevent replacement of good components, be aware the following non-EEC related areas may be cause of problem: Air Cleaner Element
Inlet Air Duct
Throttle Body
1) KOER DTC P1101: Check MAF Sensor Continuous Memory DTCs

DTC P1101, retrieved during KOER ON-DEMAND SELF-TEST, indicates MAF signal was not 0.34-1.96 volts during self-test. Drive vehicle for 6-10 minutes and repeat KOEO ON-DEMAND SELF-TEST and CONTINUOUS MEMORY SELF-TEST. If any Continuous Memory DTCs are present with KOER P1101, proceed as follows: Continuous Memory DTC P0102, go to next step.
Continuous Memory DTC P0103, go to step 20).
All other Continuous Memory DTCs, service DTCs as necessary.
If no Continuous Memory DTCs are present with KOER P1101, turn ignition switch to OFF position and go to step 3).
2) DTC P0102: Low MAF Sensor Signal To PCM

Check for broken or loose air outlet tube clamps at throttle body and air cleaner assembly. Check for holes and cracks in air outlet tube. Check for worn gaskets between MAF sensor and air cleaner. Repair as necessary. If no problems are detected, start engine and allow to idle. Check for DTCs. If KOER DTC P0505 is present, go to TEST KE, step 2). On A/T models, if engine stalls or cannot maintain idle speed, go to step 7). If KOER DTC P0505 is not present and engine idles okay, raise engine speed to 1500 RPM for 5 seconds, then return to idle. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. If MAF V PID voltage is less than.23 volt, turn ignition switch to OFF position and go to step 4). If MAF V PID voltage is.23 volt or more, go to next step.
NOTE: DTC P1101 may be caused by low battery or by use of a garage exhaust ventilation system. Ensure vehicle is vented to outside atmosphere before repeating QUICK TEST.

3) KOEO/KOER DTC P1101: MAF Output Voltage
Ensure MAF sensor is connected properly. If MAF sensor is not connected properly, repair as necessary and retest. Start engine and allow it to idle. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. If MAF V PID voltage is.46-2.44 volts, no problem is indicated at this time. Turn ignition switch to OFF position and go to TEST Z. If MAF V PID voltage is not.46-2.44 volts, turn ignition switch to OFF position and go to next step.
4) Check VPWR Voltage To MAF Sensor

Disconnect MAF sensor. Turn ignition switch to ON position. Measure voltage between ground and VPWR terminal at MAF sensor harness connector. See Fig. 32-Fig. 35. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, locate and repair open in VPWR circuit.
5) Check PWR GND Circuit

Measure voltage between positive battery terminal and PWR GND terminal at MAF sensor harness connector. If voltage is more than 10 volts, turn ignition switch to OFF position and go to next step. If voltage is 10 volts or less, locate and repair open in PWR GND circuit.
6) Check Resistance Of VPWR Circuit

Turn ignition switch to OFF position. Leave MAF sensor disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Measure resistance between VPWR terminal at MAF sensor harness connector and power relay (LS) or PCM connector terminal No. 71 (all other models). See Fig. 32-Fig. 40. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in VPWR circuit. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
7) Check MAF Circuit For Short To Ground Or MAF RTN Circuit

Disconnect scan tool from Data Link Connector (DLC). On LS, measure resistance between PCM connector terminal A31 (MAF SIG) and terminals No. A38 (MAF RTN), A24, A25, A26 and A27 (PWR GND). On all other models, measure resistance between PCM connector terminal No. 88 (MAF SIG) and terminals No. 36 (MAF RTN), 51, 77 and 103 (PWR GND). If all resistance readings are more than 10 k/ohms, go to next step. If any resistance is 10 k/ohms or less, repair short to ground and reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
8) Check MAF RTN Circuit For Short To PWR GND Circuit

On LS, measure resistance between PCM connector terminal A38 (MAF RTN) and terminals No. A24, A25, A26 and A27 (PWR GND). On all other models, measure resistance between PCM connector terminal No. 36 (MAF RTN) and terminals No. 51, 77 and 103 (PWR GND). If all resistance readings are more than 10 k/ohms, reconnect scan tool and go to next step. If any resistance is 10 k/ohms or less, repair short to ground.
9) Check MAF Circuit Voltage Cycling Integrity

Reconnect PCM connector. Turn ignition switch to ON position. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. Note reading. Connect a jumper wire between MAF RTN and PWR GND terminals at MAF sensor harness connector. Connect another jumper wire between VPWR and MAF terminals at MAF sensor harness connector. Compare voltage readings. If voltage changes from.23 volt to more than 4.5 volts, replace MAF sensor. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. If voltage does not change from.23 volt to more than 4.5 volts, proceed as follows: If DTC P1101 is present without DTC P0102, go to step 11).
If DTC P0102 is present, go to next step.
10) Check Resistance Of MAF Signal Circuit

Disconnect PCM connector(s). Measure resistance between MAF terminal at MAF sensor harness connector and PCM connector terminal A31 (MAF) on LS or terminal No. 88 (MAF) on all other models. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in MAF circuit and reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
11) Check PWR GND Circuit Resistance

Ensure ignition switch is in OFF position. Ensure PCM is disconnected. Disconnect scan tool from Data Link Connector (DLC). Measure resistance between PWR GND terminal at MAF sensor harness connector and negative battery terminal. If resistance is less than 10 ohms, go to next step. If resistance is 10 ohms or more, repair open in PWR GND circuit and reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
12) Check MAF RTN Circuit Resistance

Measure resistance between MAF RTN terminal at MAF sensor harness connector and PCM connector terminal A38 (MAF RTN) on LS or terminal No. 36 (MAF RTN) on all other models. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in MAF RTN circuit and reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 12) to step 16). No test procedures have been omitted.

16) DTC P1100: Check MAF Circuit For Intermittent Voltage To PCM

Start engine and allow it to idle. If idle is not stable, go to TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article and diagnose by symptom. Raise engine speed to 1500 RPM for 5 seconds, then return to idle. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. While observing PID, tap on MAF sensor to simulate road shock. Wiggle sensor connector. If any change in PID voltage occurs, inspect MAF sensor connector. Repair connector as necessary. If connector is okay, replace MAF sensor. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. If no change in PID voltage reading occurs, go to next step.
17) Check MAF Circuit For Intermittent Open Or Short

Turn ignition switch to ON position. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. While observing PID, wiggle small sections of wiring harness starting at MAF sensor working toward PCM. If any change in PID voltage occurs, repair wiring harness as necessary. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. If no change in PID voltage reading occurs, no problem is indicated at this time. Turn ignition switch to OFF position and go to TEST Z.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 17) to step 20). No test procedures have been omitted.

20) DTC P0103: Check MAF High Input Signal To PCM

DTC P0103 indicates MAF signal was high sometime during normal engine operation. Possible causes for this fault are: Restricted MAF Sensor Screen
MAF SIG Circuit Shorted To VPWR
Faulty MAF Sensor Or Connector
Faulty PCM
Ensure air induction system is okay. Repair if necessary. Start engine and allow to idle. If engine does not idle smoothly, repair cause of rough idle condition before continuing. If KOER DTC P0505 is present, go to TEST KE, step 2). On Ranger 2.5L A/T, if engine stalls or cannot maintain idle, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE. On all models, if engine idles smoothly, raise engine speed to 1500 RPM for 5 seconds then return to idle. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. PID value should be more than 4.60 volts. Turn ignition switch to OFF position. Disconnect MAF sensor connector.
Connect a jumper wire between PWR GND and MAF RTN terminals at MAF sensor harness connector. Start engine and allow to idle. Using scan tool, select MAF V PID from PID/DATA MONITOR & RECORD menu. If PID value does not change to less than.23 volt, turn ignition switch to OFF position, disconnect jumper wire and go to next step. If PID value changes to less than.23 volt, turn ignition switch to OFF position. Remove jumper wire and replace MAF sensor. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
21) Check MAF Circuit For Short To Power

Leave ignition switch in OFF position and MAF sensor disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. On LS, measure voltage between PCM connector terminal A31 (MAF) and terminals No. A24, A25, A26 and A27 (PWR GND). On all other models, measure voltage between PCM connector terminals No. 88 (MAF) and No. 103 (PWR GND). If voltage is less than one volt, go to next step. If voltage is one volt or more, repair MAF circuit short to power.
22) Check MAF Circuit For Short To VREF

Measure resistance between PCM harness connector MAF and VREF terminals. See WIRING DIAGRAMS article. If resistance is more than 10 k/ohms and an idle problem is still present, DO NOT diagnose DTC P0103 at this time. Check MAF sensor operation and compare MAF sensor voltages with MASS AIRFLOW table in SENSOR OPERATING RANGE CHARTS - EXCEPT VILLAGER article. If resistance is more than 10 k/ohms and an idle problem is not present, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE. If resistance is 10 k/ohms or less, repair short between MAF and VREF circuits. Reset Keep-Alive Memory (KAM). See RESETTING KEEP-ALIVE MEMORY under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 25). No test procedures have been omitted.

NOTE: If vehicle has been driven from a higher to a lower altitude for diagnosing, 3 or 4 heavy accelerations at more than 1/2 throttle must be performed to allow BARO PID to update to current altitude. BARO PID must be within plus or minus 6 Hz (plus or minus 2 in. Hg). See Fig. 41.

25) DTC P0171, P0172, P0174, P0175, P1130, P1131, P1132, P1150, P1151, P1152 Or Lean Driveability Concerns: Check Lean Conditions Related To MAF Sensor

DTCs P0171, P0172, P0174 and P0175 indicate a problem when adaptive fuel strategy senses a lean or rich condition beyond the minimum or maximum calibrated limit. DTCs P1130 and P1150 indicate when an HO2S fails to switch due to a circuit or fuel exceeding a calibrated limit. DTCs P1131, P1132, P1151 and P1152 indicate a problem when fuel control system does not detect HEGO switching for a calibrated time. Possible causes for these faults are: Fuel System

Excessive fuel pressure, leaking or contaminated fuel injectors, leaking fuel pressure regulator, low fuel pressure or engine running out of fuel or vapory recovery system fault.
Induction System

Air leaks after MAF sensor, vacuum leaks, PCV system or improperly seated engine oil dipstick.
EGR System

Leaking gasket, stuck EGR valve or leaking diaphragm or EVR.
Engine Mechanical

Engine oil overfilled, cam timing, cylinder compression or exhaust leaks before or near HO2S.
NOTE: The BARO PID value measurement is actual barometric pressure for the altitude where vehicle is being tested. Weather conditions (high or low pressure areas) may change local barometric pressure by several in. Of Hg plus or minus 3 Hz. (Plus or minus 1 in. Hg).

Ensure MAF sensor is connected. Start engine and bring to normal operating temperature. Using scan tool, access BARO, LONGFT1, LONGFT2 and MAF V PIDs. Check the following: Ensure BARO PID is about the same as barometric pressure measurement for location, day and altitude of area. See Fig. 41.
Ensure LONGFT1, LONGFT2 PIDs for all injector banks at idle are not more than minus 12 percent.
Ensure MAF V PID at idle in gear or neutral is not more than 30 percent (no more than 1.1 volt) of normal MAF V listed in appropriate pin voltage/PID value chart in appropriate PIN VOLTAGE/PID VALUE CHARTS article.
If 2 out of the 3 checks are not within specification, go to next step. If 2 out of the 3 checks are within specification and DTCs P0171, P0172, P0174, P0175, P1130, P1131, P1132, P1150, P1151 or P1152 are present, go to TEST H, step 42) for gasoline vehicles, or TEST HA, step 42) for natural gas vehicles. If 2 out of the 3 checks are within specification and no DTCs are present but driveability problem still exists, diagnose by symptom. See SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article.
NOTE: OBD-II requirements call for a fuel system DTC to be set on some vehicles although a driveability problem may not be noticeable, with or without the MAF sensor disconnected. If this should occur and BARO, LONGFT1, LONGFT2 and MAF V PID indicate a MAF sensor problem, replace MAF sensor.

26) Isolate MAF Sensor From Lean Driveability Problem
Disconnect MAF sensor connector. Start engine and drive vehicle. If lean driveability symptom (lack of power, spark knock, detonation, buck, jerk or hesitation on acceleration) is gone, replace MAF sensor. If lean driveability symptom did not disappear and DTCs P0171, P0172, P0174, P0175, P1130, P1131, P1132, P1150, P1151 or P1152 are present, go to TEST H, step 42) for gasoline vehicles, or TEST HA, step 42) for natural gas vehicles. If lean driveability symptom did not disappear and no DTCs are present, diagnose by symptom. See SYMPTOMS under TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article.

Dave H
Apr 11, 2010.


AD