Ford F150 Pickup. Instruction — part 1510

position. Using a DVOM, measure voltage between chassis ground and DPFEGR circuit at DPFEGR
sensor harness connector. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or
less, go to step 13).

12) Check DPFEGR Circuit For Short To PWR In Harness

Turn ignition switch to OFF position. 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 negative battery terminal and DPFEGR circuit at PCM harness
connector. See PCM CONNECTOR IDENTIFICATION and Fig. 240-Fig. 242 . If voltage is more
than 10.5 volts, repair short to PWR in DPFEGR circuit. If voltage is 10.5 volts or less, replace faulty
PCM.

13) Verify Scan Tool Communication

Connect jumper wire between DPFEGR and SIG RTN circuits at the DPFEGR sensor harness connector.
See

Fig. 240

-Fig. 242 . Turn ignition switch to ON position. Using scan tool, access DPFEGR PID from

PID/DATA MONITOR & RECORD menu. If a scan tool communication concern appears with the
jumper wire connected, immediately remove jumper wire. Go to step 19). If a scan tool communication
concern does not appear with the jumper wire connected, go to next step.

14) Induce Opposite DPFEGR Sensor Voltage

With jumper wire connected between DPFEGR and SIG RTN circuits at DPFEGR sensor harness
connector, use scan tool to access DPFEGR PID from PID/DATA MONITOR & RECORD menu. If
DPFEGR PID voltage reading is .05 volt or more, disconnect jumper wire and go to step 17). If DPFEGR
PID voltage reading is less than .05 volt, disconnect jumper wire and go to next step.

15) Check VREF Voltage To DPFEGR Sensor

Turn ignition switch to ON position. Using a DVOM, measure voltage between SIG RTN and VREF
circuits at DPFEGR sensor harness connector. See

Fig. 242

-Fig. 240 . If voltage is 4-6 volts, replace

DPFEGR sensor. If voltage is not 4-6 volts, go to TEST C, step 1).

17) Check DPFEGR Circuit For Open In Harness

Turn ignition switch to OFF position. Ensure DPFEGR sensor is disconnected. Disconnect PCM
connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a
DVOM, measure resistance of DPFEGR circuit between PCM harness connector and DPFEGR sensor
harness connector. See PCM CONNECTOR IDENTIFICATION and Fig. 240-Fig. 242 . If resistance
is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in DPFEGR circuit.

18) Check SIG RTN Circuit For Open In Harness

Using a DVOM, measure resistance of SIG RTN circuit between PCM harness connector and DPFEGR
sensor harness connector. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more,
repair open in SIG RTN circuit.

2003 Ford Pickup F150

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

19) Check DPFEGR Circuit For Short To VREF In Harness

Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose,
damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between
DPFEGR and VREF circuits at PCM harness connector (both VREF circuits on 150-pin PCM). See PCM
CONNECTOR IDENTIFICATION and Fig. 240-Fig. 242 . If resistance is more than 10 k/ohms,
replace PCM. If resistance is 10 k/ohms or less, repair short between DPFEGR and VREF circuits.

20) Perform Wiggle Test On DPFEGR Sensor & Circuit While Monitoring DPFEGR PID For A
Sudden Change

Turn ignition switch to ON position. Using scan tool, access DPFEGR PID from PID/DATA MONITOR
& RECORD menu. Observe DPFEGR PID value for a sudden 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 value indicates a fault. If fault is indicated, isolate and repair as
necessary. If no fault is indicated, go to TEST Z, step 1).

21) Check For Presence Of DTC P1405 With DTC P0402

If DTC P1405 is present with DTC P0402, go to step 50). If DTC P1405 is not present with P0402, go to
next step.

22) For KOER & Continuous Memory Only DTC P0402: Check EGR Flow At Idle (Vacuum Hose
Disconnected)
DTC P0402 indicates EGR MONITOR failed due to PCM detecting EGR signal at idle is more than at
KOEO by a calibrated amount of .5 volt. Possible causes for this fault are:

z

EGR Valve Stuck Open

z

EGR Vacuum Regulator (VR) Solenoid Vent Plugged

z

EGR Tube Plugged

z

DPFEGR Sensor Slow To Respond

z

Faulty DPFEGR Sensor

z

Pinched, Plugged, Damaged Or Improperly Connected Vacuum Hose

z

EGRVR Circuit Shorted To Ground

z

EGRVR Circuit Shorted To VREF Circuit

z

Faulty EGRVR Solenoid

z

Faulty PCM

Disconnect and plug EGR valve vacuum hose. Perform KOER ON-DEMAND SELF-TEST. If KOER
DTC P0402 is present, KOER self-test is unable to be performed, engine stalls or will not start, check
EGR tube, EGR valve and hoses. Repair as necessary and retest. If DTC P0402 is not present, engine
starts and does not stall, reconnect EGR valve vacuum hose and go to next step.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

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

23) Check For EGR Flow At Idle With Vacuum Hose Connected

Ensure EGR valve vacuum hose is reconnected. Perform KOER ON-DEMAND SELF-TEST. If DTC
P0402 is present, engine stalls or will not start, there may be EGR flow at idle. Go to next step. If DTC
P0402 is not present, engine starts and does not stall, fault is intermittent. Check vacuum hoses for
pinching and icing. Repair as necessary and retest. If vacuum hoses are okay, go to step 31).

24) Check EGR System Vacuum Hoses For Integrity & Proper Connection
Using vehicle's vacuum diagram label, check EGR system vacuum hoses for damage, tight connections
and correct routing. Repair as necessary. If hoses are okay, go to next step.

25) Check DPFEGR Sensor Output By Applying Vacuum With Hand Pump

Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Disconnect
pressure hoses at DPFEGR sensor. Connect hand vacuum pump to downstream connection at DPFEGR
sensor (intake manifold side or smaller diameter port). See Fig. 239. Using scan tool, access DPFEGR
PID from PID/DATA MONITOR & RECORD menu. Read the following DPFEGR PID values with
ignition switch in ON position:

z

DO NOT apply vacuum to sensor. Record DPFEGR PID value. DPFEGR PID value should be .2-
1.3 volts.

z

Using vacuum pump, apply 8-9 in. Hg (27-30 kPa) for a few seconds. DPFEGR PID value should
increase to more than 4 volts.

z

Quickly release vacuum. DPFEGR PID value should drop to less than 1.5 volts within 3 seconds of
releasing vacuum.

If any DPFEGR PID values are not as specified, replace DPFEGR sensor. If all DPFEGR PID values are
as specified, reconnect DPFEGR sensor and go to next step.

26) Check For EGR Flow At Idle With EGRVR Solenoid Disconnected
Disconnect EGR valve vacuum hose and connect vacuum gauge to hose. Start engine and allow to idle.
While observing vacuum gauge, disconnect EGRVR solenoid harness connector. If vacuum gauge
measurement stays at more than 1.6 in. Hg (5.4 kPa), go to next step. If vacuum gauge measurement is
1.6 in. Hg (5.4 kPa) or less, go to step 28).

NOTE:

A pinched or plugged EGR vacuum hose will not allow EGR valve to close
if vacuum becomes trapped between EGR vacuum regulator solenoid and
EGR valve.

NOTE:

EGR valve requires more than 1.6 in. Hg (5.4 kPa) of vacuum to begin to
open. If vacuum reading stays at more than 1.6 in. Hg (5.4 kPa) after
EGRVR solenoid connector is disconnected, this indicates a mechanical
fault in EGRVR solenoid.

NOTE:

A plugged EGRVR solenoid vent will not allow EGR vacuum to vent to
atmosphere.

2003 Ford Pickup F150

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

Fig. 243: Testing EGRVR Solenoid
Courtesy of FORD MOTOR CO.

27) Check EGRVR Solenoid Vent For Plugging
Turn ignition switch to OFF position. Disconnect EGRVR solenoid vacuum hoses. Remove EGRVR
solenoid vent cap (if removable). Remove EGRVR solenoid filter and check for blockage or icing. Plug
EGRVR solenoid vacuum supply port to EGR. Using a hand vacuum pump, apply 10-15 in. Hg (34-51
kPa) to EGRVR solenoid source port. See Fig. 243. If vacuum holds or is slow to release, EGRVR
solenoid vent may be plugged or restricted. Repair EGRVR solenoid as necessary. If unable to repair
EGRVR solenoid, replace EGRVR solenoid. If vacuum releases (solenoid vent not plugged or restricted),
replace EGRVR solenoid.

28) Check EGRVR Solenoid Coil Resistance

Turn ignition switch to OFF position. Ensure EGRVR solenoid is disconnected. Using a DVOM, measure
resistance between EGRVR solenoid terminals. If resistance is 26-40 ohms, go to next step. If resistance
is not 26-40 ohms, replace EGRVR solenoid.

29) Check EGRVR Circuit For Short To Ground In Harness

2003 Ford Pickup F150

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