Ford F150 Pickup. Instruction - part 1381

Enter this test only when all steps under QUICK TEST have been successfully completed and engine still does 
not start or if directed here from another test or chart. This test is only intended to diagnose:  

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AFCM  

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Circuitry  

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PCM Calibration  

Testing 

1) Check The AFCM SCP Circuits 
 

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Key off.  

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Disconnect the AFCM connector C1427.  

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Measure the resistance between the AFCM connector C1427 terminal No. 87, harness side and the 
DLC connector C251 terminal No. 2, harness side. See CONNECTOR IDENTIFICATION .  

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Measure the resistance between the AFCM connector C1427 terminal No. 88, harness side and the 
DLC connector C251 terminal No. 10, harness side.  

Are the resistances less than 5 ohms? If yes, go to next step. If no, repair the circuit in question. 

2) Check The PCM SCP Circuits 
 

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Disconnect PCM connector C175.  

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Measure the resistance between the AFCM connector C1427 terminal No. 87, harness side and the 
PCM connector C175 terminal No. 16, harness side. See CONNECTOR IDENTIFICATION .  

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Measure the resistance between the AFCM connector C1427 terminal No. 88, harness side and the 
PCM connector C175 terminal No. 15, harness side.  

Are the resistances less than 5 ohms? If yes, go to next step. If no, repair the circuit in question. 

3) Check The PCM Configuration 
 

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Reconnect the PCM connector C175.  

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Reconnect the AFCM connector C1427.  

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Check the PCM configuration. See PROGRAMMING .  

Is the PCM configured correctly? If yes, go to next step. If no, calibrate the PCM or replace if necessary. 
See PROGRAMMING . 

4) Check For Correct AFCM Operation 

NOTE:

During bi-fuel diagnostics, intermittent failures are possible. Perform wiggle 
test and tap lightly on relays during testing. Ensure vehicle has CNG before 
continuing with diagnostics.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/CNG

  

 

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Disconnect the AFCM.  

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Check for corrosion and pushed out pins.  

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Connect the AFCM connector and make sure it is seated correctly.  

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Operate the system and verify the concern is still present.  

Is the concern still present? If yes, install a new AFCM. If no, the system is operating correctly at this 
time. Concern may have been caused by a loose or corroded connector.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/CNG

  

2003 ENGINE PERFORMANCE

Self-Diagnostics - Bi-Fuel - Gasoline/LPG 

INTRODUCTION 

This article contains Bi-Fuel system Continuous Memory DTC, circuit and component diagnostics only. For 
diagnostic information not included within this article, see SELF-DIAGNOSTICS - CNG, FLEX-FUEL & 
GASOLINE article. If no DTCs are present or only pass codes are found during self-diagnostics, proceed to 
TROUBLE SHOOTING - NO CODES - BI-FUEL - GASOLINE/LPG article for diagnosis by symptom. If 
symptom tests check okay, perform all basic diagnostic procedures in BASIC DIAGNOSTIC PROCEDURES 
- TRUCKS - EXCEPT DIESEL article. 

SELF-DIAGNOSTIC SYSTEM 

DIAGNOSTIC FORMATS 

QUICK TEST and SYSTEM TESTS are diagnostic formats used to test and service EEC-V system. QUICK 
TEST allows technician to identify faults and retrieve Diagnostic Trouble Codes (DTC). SYSTEM TESTS are 
used to check circuits, sensors and actuators. 

Before starting any system test, follow all steps under QUICK TEST to determine appropriate system test to 
perform. If vehicle passes QUICK TEST and no driveability symptoms or intermittent faults exist, EEC-V 
system is okay. 

DIAGNOSTIC TROUBLE CODES 

During QUICK TEST, 3 types of DTC may be retrieved: Key On Engine Off (KOEO), Key On Engine 
Running (KOER) and Continuous Memory DTCs. See QUICK TEST for self-test procedures. DTCs may be 
set in PCM and/or Alternate Fuel Control Module (AFCM). Only Continuous Memory DTCs are available from 
AFCM. DTCs may be cleared from memory after DTCs have been recorded or fault has been repaired. See 
CLEARING CODES . If fault still exists after clearing DTCs, DTC will reset. 

KOEO & KOER Diagnostic Trouble Codes 

KOEO and KOER DTCS indicate faults exist at time of testing and may turn the Malfunction Indicator Light 
(MIL) on. The MIL is located on instrument cluster and may be labeled SERVICE ENGINE SOON or CHECK 
ENGINE. For additional information on KOEO and KOER DTCs, see DIAGNOSTIC TROUBLE CODES 
under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article. 
If KOEO or KOER DTCs are retrieved during KOEO ON-DEMAND SELF-TEST or KOER ON-DEMAND 
SELF-TEST, see DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - CNG, 
FLEX-FUEL & GASOLINE article. 

Continuous Memory Diagnostic Trouble Codes 

Continuous Memory DTC are retrieved after performing KOER ON-DEMAND SELF-TEST. Unlike KOEO or 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/LPG

  

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/LPG

  

KOER self-tests, which can only be activated On-Demand, Continuous Memory self-test is always active. A 
fault may or may not exist at time of checking for Continuous Memory DTCs. This self-test is helpful in 
diagnosing intermittent faults. 

After noting and/or repairing fault, clear DTCs from memory. See CLEARING CODES . Intermittent faults 
may be caused by a sensor, connector or wiring-related problem. See INTERMITTENTS in TROUBLE 
SHOOTING - NO CODES - BI-FUEL - GASOLINE/LPG article. 

RETRIEVING DIAGNOSTIC TROUBLE CODES 

DTCs are retrieved from EEC-V system through Data Link Connector (DLC), located below instrument panel, 
right of steering wheel. See Fig. 1 . Self-diagnostic test procedures are for use with Rotunda Worldwide 
Diagnostic System (WDS), New Generation Star (NGS) scan tool or equivalent. If a generic scan tool is used, 
ensure scan tool is certified to OBD-II standard. A generic scan tool may not be capable of performing all 
necessary test functions. To retrieve AFCM Continuous Memory DTCs, see AFCM CONTINUOUS 
MEMORY SELF-TEST . 

Fig. 1: Identifying Data Link Connector Terminals 
Courtesy of FORD MOTOR CO. 

READING DIAGNOSTIC TROUBLE CODES 

NOTE:

Continuous Memory DTCs should be recorded when retrieved. These DTCs may 
be used to identify intermittent faults that exist after all KOEO and KOER DTCs 
have been repaired. Some Continuous Memory DTC faults may not be valid 
after KOEO and KOER DTCs are serviced.

NOTE:

Retrieving DTC from PCM must be performed first. Alternate Fuel Control 
Module (AFCM) Continuous Memory DTCs are retrieved second.

NOTE:

If self-test will not activate or TOOL COMMUNICATION ERROR is received, see 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - Bi-Fuel - Gasoline/LPG