Ford F150 Pickup. Instruction - part 1468

Ensure MAF sensor is connected properly. Repair as necessary. Start engine and allow to idle. Using scan 
tool, access MAF V PID from PID/DATA MONITOR & RECORD menu. If MAF V PID voltage is .46-
2.44 volts, no concern is indicated at this time. Check for intermittent concern. Go to TEST Z, step 1). If 
MAF V PID voltage is not .46-2.44 volts, go to next step. 

4) Check VPWR Voltage To MAF Sensor 
 
Turn ignition switch to OFF position. Disconnect MAF sensor. Turn ignition switch to ON position. 
Using a DVOM, measure voltage between negative battery terminal and MAF sensor harness connector 
VPWR terminal. See Fig. 173, Fig. 174 and Fig. 182-Fig. 184 . 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 Between MAF Sensor & Power Relay 
 
Using a DVOM, measure voltage between positive battery terminal and MAF sensor harness connector 
PWR GND terminal. See 

Fig. 173

, Fig. 174 and Fig. 182-Fig. 184 . If voltage is more than 10 volts, go to 

next step. If voltage is 10 volts or less, locate and repair open in PWR GND circuit. 

6) Check MAF Circuit For Short To PWR GND Or MAF RTN In Harness 
 
Ensure PCM is disconnected. Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, 
measure resistance between MAF and PWR GND, and MAF RTN circuits at MAF sensor harness 
connector. See Fig. 173, Fig. 174 and Fig. 182-Fig. 184 . If both resistance measurements are more than 
10 k/ohms, go to next step. If either resistance measurement is 10 k/ohms or less, repair short to ground in 
affected circuit. 

7) Check MAF RTN Circuit For Short To PWR GND In Harness 
 
Using a DVOM, measure resistance between MAF RTN and PWR GND circuits at MAF sensor harness 
connector. See Fig. 173, Fig. 174 and Fig. 182-Fig. 184 . If resistance measurement is more than 10 
k/ohms, reconnect scan tool and go to next step. If resistance measurement is 10 k/ohms or less, repair 
short to ground in affected circuit. 

8) Check MAF Circuit For Short To PWR GND In The PCM 
 
Reconnect PCM. Using DVOM, measure resistance between MAF and PWR GND circuits at the MAF 
sensor harness connector. See Fig. 173, Fig. 174 and Fig. 182-Fig. 184 . If resistance is greater than 
10,000 ohms, reconnect scan tool and go to next step. If resistance is equal to or less than 10,000 ohms, 
replace PCM. 

9) Check MAF Circuit Voltage Cycling Integrity 
 
Turn ignition switch to ON position. Using scan tool, access MAF V PID from PID/DATA MONITOR & 
RECORD menu. Record MAF V PID reading. Connect a jumper wire between MAF sensor harness 
connector MAF RTN and PWR GND terminals, and another jumper wire between MAF sensor harness 
connector VPWR and MAF terminals. See Fig. 173, Fig. 174 and Fig. 182-Fig. 184 . If MAF V PID 
reading changes from less than .23 volt to more than 4.5 volts, replace MAF sensor. If MAF V PID 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

reading does not change from less than .23 volt to more than 4.5 volts, proceed as follows: 

z

If DTC P1101 is present without DTC P0102, go to step 11).  

z

If DTC P0102 is only DTC present, go to next step.  

10) Check MAF Circuit For Open 
 
Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance 
of MAF circuit between MAF sensor harness connector and PCM harness connector. See Fig. 173, Fig. 
174 and Fig. 182-Fig. 184 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or 
more, repair open in MAF circuit. 

11) Check PWR GND Circuit For Open In Harness 
 
Ensure ignition switch is turned to OFF position. Disconnect PCM connector(s). Disconnect scan tool 
from Data Link Connector (DLC). Using a DVOM, measure resistance of PWR GND circuit between 
MAF sensor harness connector and negative battery terminal. If resistance is less than 10 ohms, reconnect 
scan tool to DLC and go to next step. If resistance is 10 ohms or more, repair open in PWR GND circuit. 

12) Check MAF RTN Circuit For Open In Harness 
 
Using a DVOM, measure resistance of MAF RTN circuit between MAF sensor harness connector and 
PCM harness connector. See Fig. 173, Fig. 174 and Fig. 182-Fig. 184 . If resistance is less than 5 ohms, 
replace PCM. If resistance is 5 ohms or more, repair open in MAF RTN circuit. 

16) For Continuous Memory Only DTC P1100: Check MAF Circuit For Intermittent Voltage To 
PCM 
DTC P1100 indicates MAF signal exceeded maximum or fell below minimum calibrated limit during the 
last 40 warm-up cycles. Possible causes for this fault are: 

z

Poor Continuity Through MAF Sensor Connector(s) Or Harness  

z

Intermittent Open Or Short In MAF Sensor  

Start engine and allow to idle. If idle is not stable, see appropriate symptom under SYMPTOMS in 
TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article. Raise engine speed 
to 1500 RPM for 5 seconds, then allow to return to idle. Using scan tool, access MAF V PID from 
PID/DATA MONITOR & RECORD menu. While observing MAF V PID, tap on MAF sensor and 
wiggle sensor harness connector to simulate road shock. If MAF V PID voltage reading fluctuates to less 
than .23 volt (minimum), or to more than 4.6 volts (maximum), inspect MAF sensor connector. Repair 
connector as necessary. If connector is okay, replace MAF sensor. If MAF V PID voltage reading does 
not fluctuate to less than .23 volt (minimum), or to more than 4.6 volts (maximum), go to next step.

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.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

17) Check MAF Sensor Circuit For Intermittent Opens Or Shorts 
 
Turn ignition switch to ON position. Using scan tool, access MAF V PID from PID/DATA MONITOR & 
RECORD menu. While observing MAF V PID, wiggle small sections of wiring harness starting at MAF 
sensor working toward PCM. If MAF V PID voltage reading changes to less than .23 volt (minimum), or 
to more than 4.6 volts (maximum), repair wiring harness as necessary. If MAF V PID voltage reading 
does not change to less than .23 volt (minimum), or to more than 4.6 volts (maximum), no concern is 
indicated at this time. Turn ignition switch to OFF position and go to TEST Z, step 1). 

20) For KOEO, KOER & Continuous Memory DTC P0103: Check MAF Sensor Signal High Input 
To PCM 
DTC P0103 indicates MAF signal exceeded maximum calibrated limit during KOEO or KOER 
Comprehensive Component Monitor (CCM). Possible causes for this fault are: 

z

Restricted (not blocked) MAF Sensor Screen  

z

MAF Circuit Shorted To VPWR  

z

Faulty MAF Sensor Or Connector  

z

Faulty PCM  

Ensure air induction system is free of restrictions. Repair as necessary. Start engine and allow to idle. If 
KOER DTC P0505 is present, go to TEST KE, step 2). Raise engine speed to 1500 RPM for 5 seconds 
then allow to return to idle. Using scan tool, access MAF V PID from PID/DATA MONITOR & 
RECORD menu. Ensure an incorrect MAF V PID reading of more than 4.60 volts still exists. Turn 
ignition switch to OFF position. Disconnect MAF sensor connector. Connect a jumper wire between 
MAF sensor harness connector PWR GND and MAF RTN terminals. See Fig. 173, Fig. 174 and Fig. 
182-Fig. 184 . Start engine and allow to idle. If MAF V PID reading does not drop to less than .23 volt, 
turn ignition switch to OFF position, disconnect jumper wire and go to next step. If MAF V PID reading 
drops to less than .23 volt, turn ignition switch to OFF position. Remove jumper wire and replace MAF 
sensor. 

21) Check MAF Circuit For Short To VPWR In Harness 
 
Leave ignition switch turned to 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. Using a DVOM, measure voltage between MAF and PWR GND circuits at PCM harness 
connector. See PCM CONNECTOR IDENTIFICATION and Fig. 173, Fig. 174 and Fig. 182-Fig. 
184 . If voltage is less than one volt and an idle concern is not present, replace PCM. If voltage is less 
than one volt and an idle concern is still present, disregard DTC P0102 at this time and see SYMPTOMS
in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article. If voltage is one 
volt or more, repair MAF circuit for short to power. 

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.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

25) DTC P0171, P0172, P0174, P0175, P1130, P1131, P1132, P1150, P1151, P1152, P2195, P2196, 
P2197, P2198 Or Lean Driveability Concerns: Check Lean Conditions Related To MAF Sensor 
DTCs P0171, P0172, P0174, P0175, P2195, P2196, P2197 or P2198 indicate a concern 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 concern when fuel control system does not detect 
HO2S switching for a calibrated time. Possible causes for these faults are: 

z

Air Measurement System 
 
MAF sensor contaminated, damaged or malfunctioning. 

z

Fuel System 
 
Fuel pressure regulator is leaking or malfunctioning. Fuel filter plugged or dirty. Fuel pump is 
weak or check valve leaking. Leaking or contaminated fuel injectors. Low fuel pressure or running 
out of fuel. EVAP canister purge valve leaking (when canister is "clean"). Fuel supply line 
restricted. Fuel rail pressure sensor (incorrect reading). 

z

Air Induction System 
 
Air leaks after MAF sensor, vacuum leaks, PCV system leaking or sticking valve, or improperly 
seated engine oil dipstick. 

z

Exhaust System 
 
Exhaust leaks before or near HO2S, such as; exhaust manifold gasket or mating gaskets. 

z

EGR System 
 
Leaking EGR valve gasket or tube, stuck EGR valve, leaking diaphragm or EVR solenoid leaking 
vacuum. 

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 21) 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. 185.

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. Hg 
plus or minus 3 Hz (plus or minus one in. Hg).

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline