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