Ford F150 Pickup. Manual — part 1524

DTCs P1516 (IMRC or IMSC input error bank No. 1) and P1517 (IMRC or IMSC input error bank No.
2) indicate KOEO or Continuous Memory self-test failed when IMRC or IMSC monitor circuit signal fell
below or exceeded expected calibrated range. Possible cause is binding, seizing, damage or obstruction of
IMRC or IMSC mechanical system.

DTCs P1518, P1537 and P1538 may indicate IMRC or IMSC Bank No. 1 or Bank No. 2 stuck open.
KOEO or Continuous Memory self-test failed when IMRC or IMSC monitor circuit signal falls below
expected calibrated range at closed throttle. Possible causes are:

z

IMRC Or IMSC SIG Circuit Shorted To PWR GND Or SIG RTN

z

Faulty IMRC Or IMSC Actuator

z

Faulty Powertrain Control Module (PCM)

DTC P1519 indicates IMRC or IMSC may be stuck closed. KOEO or Continuous Memory self-test failed
when IMRC or IMSC monitor circuit signal exceeded expected calibrated range with IMRC or IMSC
activated. Possible causes are:

z

Faulty Vacuum Hoses

z

Faulty Vacuum Solenoid

z

Faulty Vacuum Actuator

z

IMRC Or IMSC Actuator Cable, Lever Or Gears Binding Or Seized

z

Cables Improperly Routed, Binding Or Seized

z

Faulty IMRC Or IMSC Actuator

z

Damaged Or Disconnected IMRC Or IMSC Housing Return Springs

z

Lever Return Stop Obstructed Or Bent

z

Lever Wide Open Stop Obstructed Or Bent

z

IMRC Or IMSC Monitor Circuit Open Or Shorted To VREF

z

IMRC Or IMSC SIG RTN Circuit Open Or Shorted To VPWR Or GND

z

IMRC Or IMSC VPWR Circuit Open

On models equipped with cable operated IMRC or IMSC, check IMRC or IMSC cables for correct
routing and possible binding. Ensure cable core wire (if equipped) has slack at IMRC or IMSC housing
and that lever contacts close plate stop screw. Ensure return springs operate properly and plates open and
close fully. On models with vacuum operated systems, engine must run for 20 seconds, then perform
KOEO self-test. On all models, operate IMRC or IMSC plates at intake manifold while checking for
binding and sticking. If any faults are found, go to next step. If no faults are found, go to step 17).

16) Perform IMRC Or IMSC Physical Test
On Focus 2.0L 2V, Econoline and Pickup 4.2L, and Ranger 2.3L, remove electronic actuator assembly.
On all others, disconnect IMRC or IMSC linkage or cable(s) from intake runner(s). Rotate IMRC or
IMSC lever(s) from fully closed to fully open, and back to fully closed positions while checking for

WARNING:

Be careful when operating IMRC or IMSC by hand. IMRC or IMSC
return springs are strong and may cause plates to close suddenly.

2003 Ford Pickup F150

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

binding or sticking. Feel for return spring tension of approximately 3-4 INCH. lbs. (0.34-0.45 N.m).
Levers should fully open and close without obstruction. If any faults are found, clean or repair as
necessary. After repairs, go to step 38). If no faults are found, replace IMRC or IMSC actuator. After
repairs, go to step 38).

17) Perform IMRC or IMSC Functional Test

Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Perform the
following:

z

On Focus 2.0L 2V, and Econoline and Pickup 4.2L, monitor IMRCM PID voltage.

z

On Ranger 2.3L, monitor SCVM PID voltage.

Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL
SYSTEM FUNCTIONS. Select START to turn all outputs ON. When IMRC or IMSC is commanded
ON, lever(s) should rotate to full open position. One or both levers should contact the wide open stop
(one lever being slightly off is acceptable). On Focus 2.0L 2V, Econoline and Pickup 4.2L, and Ranger
2.3L, listen for IMRC or IMSC to actuate. On all models, IMRC or IMSC levers should cycle from fully
closed and remain in fully open position while outputs are ON. If IMRC or IMSC levers do not operate as
specified, go to next step. If IMRC or IMSC levers operate as specified, go to step 25).

18) Check IMRC Or IMSC Actuator VPWR Circuit For An Open In Harness

Turn ignition switch to OFF position. Disconnect IMRC or IMSC actuator harness connector. Turn
ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and
VPWR circuit at IMRC or IMSC actuator harness connector. See Fig. 251-Fig. 255 . If voltage is more
than 10.5 volts, go to step 20) (Focus 2.0L 2V, Econoline and Pickup 4.2L, and Ranger 2.3L), or go to
next step (all others). If voltage is 10.5 volts or less, repair open in VPWR circuit. After repairs, go to step
38).

19) Check IMRC Or IMSC GND Circuits For Open In Harness

Using a DVOM, measure voltage between GND and VPWR circuits at IMRC or IMSC actuator harness
connector. See Fig. 251-Fig. 255 . If voltage is more than 10.5 volts, go to next step. If voltage is 10.5
volts or less, repair open in GND circuit. After repairs, go to step 38).

20) Verify Driver Circuit Function

Turn ignition switch to OFF position. Ensure scan tool is connected to DLC. Connect a test light between
VPWR and SIGNAL circuits at IMRC or IMSC actuator harness connector. Test light should be off.
Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL
SYSTEM FUNCTIONS. Select START to turn all outputs ON. If test light illuminates, go to step 32). If

NOTE:

On Focus 2.0L 2V, Econoline and Pickup 4.2L, and Ranger 2.3L, if IMRCM
or SCVM PID voltage reading is less than one volt, or if IMRC or IMSC
plates open immediately when ignition switch is turned to ON position (all
others), go to step 23).

2003 Ford Pickup F150

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

test light does not illuminate, go to next step.

21) Check IMRC Or IMSC Driver Circuit For Open In Harness

Disconnect PCM connector(s). Using a DVOM, measure resistance of IMRC or IMSC SIGNAL circuit
between PCM harness connector and IMRC or IMSC actuator harness connector. See Fig. 251-Fig. 255 .
If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in IMRC or
IMSC SIGNAL circuit. After repairs, go to step 38).

22) Check IMRC Or IMSC Driver Circuit For Short To VPWR In Harness

Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and
IMRC or IMSC SIGNAL circuit at actuator harness connector. See Fig. 251-Fig. 255 . If voltage is 10.5
volts or more, repair short to VPWR. After repairs, go to step 38). If voltage is less than 10.5 volts, check
for intermittent faults. Go to TEST Z, step 1). If no intermittent faults are found, replace PCM. After
repairs, go to step 38).

23) Check IMRC Or IMSC Driver Circuit For Short To GND Or Monitor Circuit With PCM
Connected

Turn ignition switch to OFF position. Using a DVOM, measure resistance between SIGNAL circuit, and
PWR GND and SIG RTN circuits at IMRC or IMSC actuator harness connector. See Fig. 251-Fig. 255 .
If all resistance measurements are more than 10 k/ohms, replace IMRC or IMSC actuator. After repairs,
go to step 38). If any resistance measurement is 10 k/ohms or less, go to next step.

24) Check IMRC Or IMSC Driver Circuit For Short To GND Or Monitor Circuit With PCM
Disconnected

Ensure ignition switch is turned to OFF position. Disconnect PCM connector(s). Using a DVOM,
measure resistance between SIGNAL circuit, and PWR GND, SIG RTN and IMRCM circuits at IMRC or
IMSC actuator harness connector. See Fig. 251-Fig. 255 . If all resistance measurements are more than 10
k/ohms, replace PCM. After repairs, go to step 38). If any resistance measurement is 10 k/ohms or less,
repair short between affected circuits. After repairs, go to step 38).

25) Check IMRCM Or SCVM PID To Determine Path For Possible Short

Ensure ignition switch is turned to ON position. Using scan tool, access IMRCM or SCVM PID from
PID/DATA MONITOR & RECORD menu. On models with 3.8L or 4.2L, IMRCM or SCVM PID
voltage reading should be about 2.5 volts. On all others, IMRCM or SCVM PID voltage reading should
be about 5 volts. On all models, if IMRCM or SCVM PID voltage reading is as specified, go to next step.
If IMRCM or SCVM PID voltage reading is not as specified, go to step 30).

26) Check IMRCM Or SCVM PID To Determine A Short To VPWR

Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL
SYSTEM FUNCTIONS. Access IMRCM or SCVM PID from PID/DATA MONITOR & RECORD
menu. Select START to turn all outputs ON. If IMRCM or SCVM PID voltage reading is less than one

2003 Ford Pickup F150

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

volt, go to next step. If IMRCM or SCVM PID voltage reading is one volt or more, go to step 32).

27) Check IMRCM Or SCVM Circuit For Short To VPWR At Harness Connector

Disconnect IMRC or SCVM harness connector. Turn ignition switch to ON position. Using a DVOM,
measure voltage of IMRCM or SCVM circuit between chassis ground and IMRC or SCVM harness
connector. See Fig. 251-Fig. 255 . If voltage is more than 10.5 volts, go to next step. If voltage is 10.5
volts or less, go to step 29).

28) Check IMRCM Or SCVM Circuit For Short To PWR With PCM Disconnected

Turn ignition switch to OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position.
Using a DVOM, measure voltage between chassis ground and IMRCM or SCVM circuit at IMRC or
SCVM harness connector. If voltage is less than 10.5 volts, replace PCM. After repairs, go to step 38). If
voltage is 10.5 volts or more, repair short to PWR in IMRC or SCVM circuit. After repairs, go to step
38).

29) Check IMRCM Or SCVM Circuit For Short To VPWR At IMRC Or IMSC Actuator

Turn ignition switch to OFF position. Using a DVOM, measure resistance between IMRC or SCVM
harness connector VPWR and IMRCM or SCVM terminals. See Fig. 251-Fig. 255 . If resistance is 10
k/ohms or less, replace IMRC or IMSC actuator. If resistance is more than 10 k/ohms, check for
intermittent faults. Go to TEST Z, step 1). After repairs, go to step 38). If no intermittent faults are found,
replace PCM. After repairs, go to step 38).

30) Check IMRCM Or SCVM Circuit For Short To Ground

Ensure ignition switch is turned to ON position. Using scan tool, access IMRCM or SCVM PID from
PID/DATA MONITOR & RECORD menu. Observe IMRCM or SCVM PID voltage reading while
disconnecting IMRC or SCVM harness connector. If IMRCM or SCVM PID voltage reading changed
from less than one volt to VREF voltage, replace IMRC or IMSC actuator. After repairs, go to step 38). If
voltage does not change from less than one volt to VREF voltage, go to next step.

31) Check IMRCM Or SCVM Circuit For Short To Ground In Harness

Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance
between IMRCM or SCVM circuit, and SIG RTN circuit at IMRC or SCVM harness connector, and
chassis ground. See Fig. 251-Fig. 255 . If all resistance measurements are more than 10 k/ohms, replace
PCM. After repairs, go to step 38). If any resistance measurement is 10 k/ohms or less, repair short to SIG
RTN or chassis ground. After repairs, go to step 38).

32) Check Monitor Circuit Response

Turn ignition switch to OFF position. Disconnect IMRC or SCVM harness connector. Ensure scan tool is
connected to DLC. Turn ignition switch to ON position. Using scan tool, access IMRCM or SCVM PID
from PID/DATA MONITOR & RECORD menu. Observe IMRCM or SCVM PID voltage reading while
connecting a jumper wire between chassis ground and IMRCM or SCVM circuit at IMRC or SCVM

2003 Ford Pickup F150

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