Ford F150 Pickup. Manual — part 1515

restrictions. If restrictions are present and are unable to be removed, replace exhaust manifold. Perform
DRIVE CYCLES. Ensure CATALYST MONITOR PROCEDURE is performed to verify repair.

13) Check Manifold Vacuum With Muffler & Tailpipe Assembly Disconnected

Leave tachometer and vacuum gauge connected. Disconnect muffler and tailpipe assembly from rear of
catalytic converter. Start engine and gradually raise engine speed to 2000 RPM. Observe vacuum gauge
reading response while maintaining increased engine RPM. If manifold vacuum is now okay, fault is in
muffler and tailpipe assembly. Repair as necessary. Perform

DRIVE CYCLES

. Ensure CATALYST

MONITOR PROCEDURE is performed to verify repair. If manifold vacuum is still not okay, fault is in
catalytic converter. Replace catalytic converter. After replacing catalytic converter, check muffler and
tailpipe assembly for debris from faulty catalytic converter. Perform DRIVE CYCLES. Ensure
CATALYST MONITOR PROCEDURE is performed to verify repair.

TEST HG: PCV SYSTEM

Diagnostic Aids

This test is performed when directed here from one of the following symptoms in TROUBLE SHOOTING -
NO CODES - CNG & GASOLINE article:

z

Rough Or Rolling Idle, Stalls, Misses, Hesitation Or Surge

z

Hard Start/Long Crank Or Erratic Start/Crank

z

Slow Return To Idle

z

Spark Knock

z

Poor Fuel Economy

z

High Oil Consumption

z

Exhaust Smoke

Use this test to diagnose Positive Crankcase Ventilation (PCV) valve and related vacuum hoses.

Testing

1) Check Power And Ground Circuits At Heated PCV Valve

Disconnect the heated PCV valve harness connector. Start engine. Measure the voltage at the heated PCV
valve harness connector. If the voltage is greater than 10.5 volts, go to next step. If the voltage is 10.5
volts or less, go to step 3.

2) Check Resistance Of Heated PCV Valve

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.

2003 Ford Pickup F150

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

Measure the resistance between both pins at the heated PCV valve. If the resistance reading is 28-35
ohms, go to step 4). If the resistance reading is not 28-35 ohms, replace heated PCV valve.

3) Check Battery Voltage To Heated PCV Valve Circuit

Measure B(+) circuit voltage at the heated PCV valve harness connector. If the voltage greater than 10.5
volts, check the heated PCV valve ground circuit. Repair as necessary. Turn ignition switch to OFF
position. Check condition of related fuse(s). If okay, repair open circuit. If fuse is damaged, check B(+)
circuit for short to ground before replacing.

4) Stuck PCV Valve Check

Ensure PCV valve maintenance schedule has been followed. Ensure proper PCV valve is installed.
Remove PCV valve. Shake valve and listen for rattle. If PCV valve rattles when shaken, install PCV
valve and go to next step. Replace PCV valve if it does not rattle when shaken. Verify repair.

5) PCV System Check

Start engine and warm to normal operating temperature. Disconnect fresh air hose from remote air cleaner
or outlet tube connecting MAF sensor to throttle body. Place a stiff piece of paper over end of hose. If
vacuum from hose does not hold paper in place for one minute, go to next step. If vacuum from hose
holds paper in place for one minute, PCV system is okay. Return to appropriate symptom under
SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article to
complete testing.

6) Evaporative Emission System Check

Disconnect evaporative emission hose from PCV system and plug connector. Again, place a stiff piece of
paper over end of hose. If vacuum from hose does not hold paper in place for one minute, isolate vacuum
leak or restriction in PCV system and repair as necessary. If vacuum from hose holds paper in place for
one minute, PCV system is working properly at this time. Go to SYSTEM TESTS (EVAPORATIVE
EMISSION) to diagnose EVAP system vacuum leak.

TEST HH: EXHAUST GAS RECIRCULATION SYSTEM MODULE

Diagnostic Aids

Perform this test when instructed by QUICK TEST. This test is intended to diagnose the following:

z

Exhaust Gas Recirculation System Module (ESM).

z

Differential pressure feedback EGR sensor.

z

Differential pressure feedback EGR sensor pressure hoses.

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.

2003 Ford Pickup F150

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

z

Vacuum lines.

z

Harness circuits: VREF, DPFE, SIG, SIG RTN, EVR, EVR PWR.

z

Powertrain Control Module (PCM).

Fig. 246: Identifying Exhaust Gas Recirculation System Components
Courtesy of FORD MOTOR CO.

For exhaust gas recirculation system connector terminal identification, see Fig. 195.

Testing

1) For KOEO, KOER & Continuous Memory DTC P0405 & P1400: Determine Present DPFEGR
PID Voltage

DTC P0405 and P1400 indicates EGR MONITOR failed due to average voltage to PCM dropping below
minimum calibrated limit of less than .2 volt. Possible causes for this fault are:

z

DPFEGR Circuit Shorted To GND Or SIG RTN Circuit

z

Faulty DPFEGR Sensor

z

VREF Circuit Shorted To GND Or SIG RTN Circuit

z

Faulty PCM

2003 Ford Pickup F150

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

Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool,
access DPFEGR PID from PID/DATA MONITOR & RECORD menu. If DPFEGR PID voltage is less
than .2 volt, fault is currently present. Go to next step. If voltage is .2 volt or more, fault is intermittent.
Go to step 5).

2) Attempt To Induce Opposite DPFEGR Sensor Voltage

Turn ignition switch to OFF position. Disconnect ESM harness connector. Turn ignition switch to ON
position. Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. If PID
voltage is 4-6 volts, replace DPFEGR sensor. If PID voltage is not 4-6 volts, go to next step.

3) Check VREF And SIG RTN Circuits For Open In Harness To DPFEGR Sensor

Using a DVOM, measure voltage between SIG RTN and VREF circuits at ESM harness connector. See
Fig. 195. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to TEST C, step 1).

4) Check DPFEGR Circuit For Short To Ground & SIG RTN In Harness

Disconnect scan tool from Data Link Connector (DLC). Turn ignition switch to OFF position. Disconnect
PCM connector(s). Using a DVOM, measure resistance between DPFEGR circuit, and SIG RTN circuit
at PCM harness connector, and negative battery terminal. See PCM CONNECTOR
IDENTIFICATION and Fig. 195. If both resistance measurements are more than 10 k/ohms, replace
PCM. If either resistance measurement is 10 k/ohms or less, repair short to ground or SIG RTN in
DPFEGR circuit.

5) Perform Wiggle Test On DPFEGR Sensor (On The ESM) & Circuit While Monitoring DPFEGR
PID For A Sudden Change

Ensure ignition switch is in ON position. Using scan tool, access DPFEGR PID from PID/DATA
MONITOR & RECORD menu. Observe DPFEGR PID voltage reading for change while tapping lightly
on DPFEGR sensor, and shaking and bending DPFEGR sensor wiring harness and connector to simulate
road shock. A sudden change in DPFEGR PID voltage reading indicates a fault. If fault is indicated,
isolate and repair as necessary. If no fault is indicated, go to TEST Z, step 1).

10) For KOEO, KOER & Continuous Memory DTC P0403, P0406, P1401: Determine Present
DPFEGR PID Voltage

DTC P0406 and P1401 indicate EGR MONITOR failed due to average voltage to PCM exceeding
maximum calibrated limit of 4.5 volts. Possible causes for this fault are:

z

Open In DPFEGR Or SIG RTN Circuit

z

VREF Or DPFEGR Circuit Shorted To PWR

z

Faulty DPFEGR Sensor

z

Faulty PCM

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 5) to step 10). No test procedures have been omitted.

2003 Ford Pickup F150

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