Ford F150 Pickup. Instruction — part 1338

2003 ENGINE PERFORMANCE

System & Component Testing - Bi-Fuel - Gasoline/CNG

INTRODUCTION

COMPUTERIZED ENGINE CONTROLS

POWERTRAIN CONTROL MODULE

Ground Circuits

Turn ignition off. Disconnect PCM 104-pin connector. PCM is located on right rear of engine compartment.
Using DVOM, check for continuity between chassis ground and PCM harness connector terminals No. 3, 25,
51, 76 and 103. See Fig. 1. If continuity exists, see POWER CIRCUITS. If continuity does not exist, repair
open in affected ground circuit. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS - F150
article in ELECTRICAL.

Power Circuits

WARNING:

Before performing any tests or diagnostics on CNG components or
systems, read all cautions and warnings in CNG/LPG SAFETY
PRECAUTIONS article in GENERAL INFORMATION.

NOTE:

System and component testing included in this article is for alternative fuel
systems only. For gasoline fuel system and component testing, see SYSTEM &
COMPONENT TESTING - GASOLINE article. Since many computer-controlled
and monitored components set a Diagnostic Trouble Code (DTC) when a
malfunction occurs, check for Powertrain Control Module (PCM) DTCs and
Alternative Fuel Control Module (AFCM) DTCs prior to testing an individual
system or component. Perform QUICK TEST procedures in SELF-DIAGNOSTICS
- CNG, FLEX-FUEL & GASOLINE article, or QUICK TEST procedures in SELF-
DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article. If no DTCs are present,
perform SYMPTOM DIAGNOSIS under SYMPTOMS in TROUBLE SHOOTING -
NO CODES - BI-FUEL - GASOLINE/CNG article to diagnose driveability
problems existing when a hard fault code is not present. For specifications, see
appropriate ON-VEHICLE ADJUSTMENTS - TRUCKS or SERVICE &
ADJUSTMENT SPECIFICATIONS - EXCURSION & PICKUP article.

NOTE:

Testing individual components does not isolate short or open circuits. Perform
all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-
megohm input impedance, unless stated otherwise in test procedure. Use
ohmmeter to isolate shorted or open wiring harness. For identification of
circuits and terminals referenced in test procedures, see ENGINE
PERFORMANCE in SYSTEM WIRING DIAGRAMS - F150 article in ELECTRICAL.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE System & Component Testing - Bi-Fuel - Gasoline/CNG

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE System & Component Testing - Bi-Fuel - Gasoline/CNG

1. Ensure ignition is OFF. Using DVOM, check for battery voltage between chassis ground and PCM Keep

Alive Memory Power (KAPWR) terminal No. 55. See Fig. 1. If battery voltage is present, go to next step.
If battery voltage is not present, check for open in KAPWR circuit or fuse No. 2 (5-amp), located in
central junction box. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS - F150
article in ELECTRICAL.

2. Turn ignition on. Using DVOM, check for battery voltage between chassis ground and VPWR at PCM

connector terminals No. 71 and 97. If battery voltage is not present, power is not being supplied from
PCM power relay. See TEST B: EEC-V POWER RELAY under SYSTEM TESTS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

Fig. 1: Identifying Powertrain Control Module Connector Terminals
Courtesy of FORD MOTOR CO.

ALTERNATIVE FUEL CONTROL MODULE

Ground Circuits

Turn ignition off. Disconnect AFCM 90-pin connector. AFCM is located in right front of engine compartment.
Using DVOM, check for continuity between chassis ground and AFCM connector terminals No. 1, 2, 3, 4, 17,
19, 21, 23, and 75. See Fig. 2. If continuity exists, go to next step. If continuity does not exist, repair open in
affected ground circuit. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS - F150 article in
ELECTRICAL.

NOTE:

Alterative Fuel Control Module (AFCM) is only used on bi-fuel vehicles.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE System & Component Testing - Bi-Fuel - Gasoline/CNG

Fig. 2: Identifying AFCM Connector C1427 Terminals
Courtesy of FORD MOTOR CO.

Power Circuits

Turn ignition off. Ensure AFCM 90-pin connector is disconnected. Turn ignition on. Using DVOM, check for
battery voltage between chassis ground and AFCM VPWR terminals No. 45 and 60. See Fig. 2. If battery
voltage is not present, power is not being supplied from bi-fuel relay module. Repair open in affected circuit or
bi-fuel relay module as necessary. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS -
F150 article in ELECTRICAL.

ENGINE SENSORS & SWITCHES

ALT FUEL SWITCH

For ALT fuel switch or circuit testing, see TEST NB: ALT FUEL INDICATOR under SYSTEM TESTS in
SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

FUEL RAIL PRESSURE SENSOR

Faults in Fuel Rail Pressure (FRP) sensor or circuit should set a Diagnostic Trouble Code (DTC). Perform
QUICK TEST in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article. If no DTC has been set, go to
TEST DE: FUEL RAIL PRESSURE SENSOR under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-
FUEL - GASOLINE/CNG article for FRP sensor and circuit testing.

FUEL RAIL TEMPERATURE SENSOR

Faults in Fuel Rail Temperature (FRT) sensor or circuit should set a Diagnostic Trouble Code (DTC). Perform
QUICK TEST in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article. If no DTC has been set, see
TEST DA: FUEL RAIL TEMPERATURE under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/CNG article for FRT sensor and circuit testing.

HEATED OXYGEN SENSOR

Faults in Heated Oxygen Sensor (HO2S) or circuit should set a Diagnostic Trouble Code (DTC). Perform
QUICK TEST in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

INERTIA FUEL SHUTOFF SWITCH

Turn ignition off. Locate Inertia Fuel Shutoff (IFS) switch, behind right kick panel. Shake or jar IFS switch to
cause switch to open. IFS switch reset button should pop up. Fuel pump should not operate and vehicle should
not start. Push down on reset button. Restart engine. Fuel pump should operate.

NOTE:

For additional gasoline-related sensor and switch testing procedures, see
SYSTEM & COMPONENT TESTING - GASOLINE article.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE System & Component Testing - Bi-Fuel - Gasoline/CNG

RELAYS & SOLENOIDS

AUXILIARY RELAY BOX NO. 1

Perform QUICK TEST in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article. If no DTC has been
set, repair by symptom. See SYMPTOM DIAGNOSIS under SYMPTOMS in TROUBLE SHOOTING - NO
CODES - BI-FUEL - GASOLINE/CNG article

FUEL RAIL SOLENOID

For fuel rail solenoid or circuit testing, see NO START/HARD START IN ALT FUEL - ALT FUEL
SWITCH INDICATOR IS ON, THEN OFF under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/CNG article.

FUEL TANK VALVE

For fuel tank solenoid or circuit testing, see NO START/HARD START IN ALT FUEL - ALT FUEL
SWITCH INDICATOR IS ON, THEN OFF under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/CNG article.

FUEL SYSTEM SAFETY PRECAUTIONS

BI-FUEL SYSTEM

NOTE:

If a fault exists in auxiliary relay box No. 1, an AFCM DTC or driveability concern
should be present.

NOTE:

Auxiliary relay box No. 1 contains bi-fuel power relay and fuel pump cut-off
relay.

CAUTION: Natural gas in fuel system is at high pressure at all times. To avoid injury

or fire, release fuel pressure from fuel system before disassembling any
fuel system component. To release fuel system pressure, follow pressure
relief procedure. See FUEL SYSTEM PRESSURE RELEASE under FUEL
SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-
FUEL - GASOLINE/CNG article. After performing fuel system pressure
relief procedure, a small amount of pressure 3 psi (21 kPa) will remain in
fuel rail, and high pressure still exists in fuel tanks. Prevent combustion
from escaping fuel; no smoking, open flames or any kind of arcing.

WARNING:

Use care to prevent combustion from fuel spillage. No smoking, open
flames or any kind of arcing.

NOTE:

Compressed Natural Gas (CNG) may also be referred to as natural gas. Natural

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE System & Component Testing - Bi-Fuel - Gasoline/CNG