Ford F150 Pickup. Instruction — part 1340

2003 ENGINE PERFORMANCE

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

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 article in
ELECTRICAL.

Power Circuits

WARNING:

Before performing any tests or diagnostics on LPG components or
systems, read all cautions and warnings in 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/LPG article. If no DTCs are present,
perform SYMPTOM DIAGNOSIS under SYMPTOMS in TROUBLE SHOOTING -
NO CODES - BI-FUEL - GASOLINE/LPG article to diagnose driveability problems
existing when a hard fault code is not present. For specifications, see
appropriate ON-VEHICLE ADJUSTMENTS - TRUCKS or appropriate SERVICE &
ADJUSTMENT SPECIFICATIONS 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 article in ELECTRICAL.

2003 Ford Pickup F150

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

2003 Ford Pickup F150

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

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 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 compuvalve 64-pin connector. Compuvalve is located in right rear corner of
engine compartment. Using DVOM, check for continuity between chassis ground and compuvalve connector
terminals No. 57, 59, 61, 62, 63 and 64. 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 article in ELECTRICAL.

Fig. 2: Identifying Compuvalve Connector C1294 Terminals
Courtesy of FORD MOTOR CO.

Power Circuits

Turn ignition off. Ensure compuvalve 64-pin connector is disconnected. Turn ignition on. Using DVOM, check
for battery voltage between chassis ground and compuvalve VPWR terminals No. 2, 11 and 13. See Fig. 2 . If

NOTE:

Alternative Fuel Control Module (AFCM) is contained within compuvalve
assembly. AFCM is only used on bi-fuel vehicles.

2003 Ford Pickup F150

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

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 article in ELECTRICAL.

ENGINE SENSORS & SWITCHES

SENSORS

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/LPG article. If no DTC has been set, go to
TEST DC: FUEL RAIL PRESSURE under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/LPG 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/LPG article. If no DTC has been set, see
TEST DA: FUEL RAIL TEMPERATURE under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/LPG 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
TEST H: FUEL CONTROL in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG article.

Manifold Absolute Pressure Sensor

Faults in Manifold Absolute Pressure (MAP) sensor or circuit should set a Diagnostic Trouble Code (DTC).
Perform QUICK TEST in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG article. If no DTC has been
set, see TEST DB: MAP/BARO SENSOR under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/LPG article for MAP sensor and circuit testing.

Reference Voltage

Faults in sensor reference voltage or signal return circuits should set a DTC. Perform QUICK TEST in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article. If no DTC has been set, see TEST C:
REFERENCE VOLTAGE under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article for sensor reference voltage and signal return circuit testing.

SWITCHES

ALT Fuel Switch

NOTE:

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

2003 Ford Pickup F150

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

For ALT fuel switch or circuit testing, repair by symptom. See SYMPTOM DIAGNOSIS under SYMPTOMS
in TROUBLE SHOOTING - NO CODES - BI-FUEL - GASOLINE/LPG 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.

RELAYS & SOLENOIDS

RELAYS

Bi-Fuel Relay Module

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

FUEL SYSTEM SAFETY PRECAUTIONS

BI-FUEL SYSTEM

Liquefied Petroleum Gas

Avoid inhaling Liquefied Petroleum Gas (LPG) or occupying confined areas containing LPG. LPG (propane) is

NOTE:

If a fault exists in bi-fuel relay module, an AFCM DTC or driveability concern
should be present.

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 & INSTALLATION - F150 PICKUP - BI-FUEL -
GASOLINE/LPG 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:

Liquefied Petroleum Gas (LPG) may also be referred to as propane. Propane is
heavier than air.

2003 Ford Pickup F150

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