Ford F150 Pickup. Instruction — part 1533

2003 Ford Pickup F150

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

Fig. 280: Coil-On-Plug Spark Diagram
Courtesy of FORD MOTOR CO.

COIL PACK FIRING ORDERS

COIL-ON-PLUG FIRING ORDERS

Testing

1) For KOER & Continuous Memory Only DTC P0350: Preliminary Test
DTC P0350 is set when PCM does not receive a valid Ignition Driver Module (IDM) pulse signal from
ignition module integrated in PCM. Possible causes are:

z

IGN START/RUN circuit open or shorted.

z

Coil driver circuit open, or shorted to GND or VPWR.

z

Faulty coil.

z

Faulty Powertrain Control Module (PCM).

Ensure battery is fully charged and all accessories are off. Check all wiring harnesses and connectors for
damage, burned or overheated insulation. Ensure all coils and plug wires are securely connected. Repair
as necessary and perform DRIVE CYCLES. Ensure OBD-II DRIVE CYCLES is performed to verify
repair. If no concerns are found, proceed as follows:

z

For coil pack applications using engine analyzer, go to next step.

z

For coil pack applications not using engine analyzer, go to step 20).

z

For coil on plug applications, go to step 15).

Application

Firing Order

4-Cylinder

1-3-4-2

V6

1-4-2-5-3-6

Application

Firing Order

V6

1-4-2-5-3-6

V8

LS & Thunderbird

1-5-4-2-6-3-7-8

All Others

1-3-7-2-6-5-4-8

V10

1-6-5-10-2-7-3-8-4-9

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

For diagnostic procedures to provide accurate results, calibration of
engine analyzer must be maintained. Refer to equipment manufacturer's
instruction for proper procedure to calibrate engine analyzer. If equipment
manual is not available, an estimate of calibration can be made by
connecting Spark Tester (D81P-6666-A), to a properly operating ignition
system and measuring firing voltage of spark tester only. Spark tester
firing voltage should be approximately 12 kilovolts.

2003 Ford Pickup F150

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

2) Connect Engine Analyzer
Install engine analyzer to diagnose concerns with secondary side of ignition system and go to next step.

3) Check For Ignition Pattern

Crank engine and observe scope pattern. If scope pattern is not flat, go to next step. If scope pattern is flat
(no spark on all cylinders), turn ignition switch to OFF position and go to TEST B, step 5) (LS and
Thunderbird), or check IGN START/RUN circuit (all others). Check all related fuses and fuse links. If
fuse or fuse link is blown, check IGN START/RUN circuit for short to GND. Repair as necessary and
perform DRIVE CYCLES. Ensure OBD-II DRIVE CYCLES is performed to verify repair.

Fig. 281: Identifying Normal Spark Pattern
Courtesy of FORD MOTOR CO.

4) Check For Normal Ignition Pattern
Start engine and allow to idle. If engine does not start, crank engine. Observe scope pattern and check
average spark output voltage and variation of pattern. See Fig. 281. If spark patterns are not even and

NOTE:

Spark plugs are fired up to 4 strikes per ignition cycle. Multi-strike
operating mode is dependent on PCM calibration and is operational only
with engine speed at less than 2000 RPM. With engine speed at more than
2000 RPM, spark plugs are fired once per ignition cycle.

2003 Ford Pickup F150

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

average spark plug firing voltage is not 9-15 kilovolts, go to next step. If concern is intermittent and spark
pattern is even and average value of spark plug firing voltage is 9-15 kilovolts, fault is unable to be
duplicated at this time. Go to TEST Z, step 1). If average spark plug firing voltage is 9-15 kilovolts,
ignition system is functioning properly. If directed here from SYMPTOMS in TROUBLE SHOOTING -
NO CODES - CNG, FLEX-FUEL & GASOLINE article, return to symptom test that directed you here. If
directed here from TEST HD, step 3), return to TEST HD, step 4). If directed here from TEST A, step 6),
return to TEST A, step 6).

5) Check For 2 Missing Spark Patterns On Same Coil

Observe scope pattern and check for 2 missing spark patterns from same coil. See Fig. 282. If spark is not
missing from 2 cylinders on same coil, go to next step. If spark is missing from 2 cylinders on same coil,
check spark plug wires and spark plugs on missing cylinders. Measure resistance of spark plug wires.
Spark plug wire resistance should be 7 k/ohms or less per foot. Measure resistance of spark plugs. Spark
plug resistance should be 2-20 k/ohms. Repair as necessary and retest. If spark plug wires and spark plugs
are okay, go to TEST JE, step

1)

.

Fig. 282: Identifying 2 Missing Spark Patterns On Same Coil
Courtesy of FORD MOTOR CO.

6) Check For Missing Spark Pattern

Observe scope pattern and check for missing spark pattern. See Fig. 283. If spark is present from all

2003 Ford Pickup F150

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