Ford F150 Pickup. Instruction — part 1532

Fig. 278: Identifying Generator Wiring Harness Connector Terminals (Marauder, Sable, Taurus &
Windstar)
Courtesy of FORD MOTOR CO.

Testing

1) For KOER & Continuous Memory Only DTCs P0622, P1244, P1245 & P1246: Verify Generator
Drive Function
The PCM monitors generator load from the generator/regulator in the form of frequency. The frequency
range is determined by the temperature of the voltage regulator where 97 percent represents full load,
below 6 percent means no load. Possible causes are:

z

Generator circuit short to GND.

z

Generator circuit short to PWR.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

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

z

Generator circuit open.

z

Generator drive mechanism.

z

Damaged generator/regulator assembly.

z

Damaged PCM.

Check generator drive belt condition and tension. Start engine and verify generator is turning. Repair as
necessary. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING
SYSTEMS. If no faults are found, go to step 3) (for Expedition, Explorer, Mountaineer and Navigator) or
go to next step (all others).

2) Verify Charging System Is EEC Controlled

Turn ignition switch to OFF position. Disconnect negative, then positive battery cable. Disconnect
generator connector. Using a DVOM, measure resistance between BATT-SENSE and GEN-COM
circuits at generator connector (except LS and Thunderbird). For LS and Thunderbird, measure resistance
between GEN-MON and ground. See Fig. 275-Fig. 278 . If resistance is 950-1050 ohms (except LS and
Thunderbird) or 53-203 ohms (LS and Thunderbird), go to next step. If resistance is not as specified,
replace generator/regulator assembly.

3) Check Battery Sense Voltage At Battery

Reconnect generator connector. Reconnect battery cables to battery. Using a DVOM, measure voltage
between battery terminals. Note voltage measurement. Using a DVOM, measure voltage between
negative battery terminal and BATT-SENSE circuit at generator harness connector. If voltage is within .5
volt (plus or minus) of battery voltage measurement, go to next step (for Expedition, Explorer,
Mountaineer and Navigator), or go to step 5) (all others). If voltage is not within .5 volt of battery voltage
measurement, repair BATT-SENSE circuit as necessary.

4) Check EEC Control Circuit In PCM

Turn ignition switch to OFF position. Disconnect generator and PCM harness connectors. Measure
resistance between the I-Line and VPWR through the PCM where applicable for Expedition/Navigator.
Measure resistance between the I-Line and ground through the PCM where applicable for
Explorer/Mountaineer. If the resistances are within the ranges in the table, go to next step. See
RESISTANCE VALUES FOR PCM CIRCUITS table. If the resistances are not within the ranges in
the table, replace PCM.

RESISTANCE VALUES FOR PCM CIRCUITS

5) Check GEN-MON & GEN-COM Circuits For Short To PWR

Turn ignition switch to OFF position. Disconnect PCM connector(s). Disconnect generator connector.

Vehicle

Range (Ohms)

Expedition & Navigator

1550-1650

Explorer & Mountaineer

100-150

2003 Ford Pickup F150

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

Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal
and GEN-COM and GEN-MON circuits at PCM harness connector. See Fig. 275-Fig. 278 . If both
voltage measurements are .5 volt or less, go to next step. If either voltage measurement is more than .5
volt, repair short to PWR in affected circuit.

6) Check GEN-COM & GEN-MON Circuits For Short To GND

Turn ignition switch to OFF position. Using a DVOM, measure resistance between negative battery
terminal and GEN-COM and GEN-MON circuits at PCM harness connector. If both resistance
measurements are more than 10 k/ohms, go to next step. If either resistance measurement is 10 k/ohms or
less, repair short to GND in affected circuit.

7) Check GEN-COM & GEN-MON Circuits For Open

Using a DVOM, measure resistance of GEN-COM and GEN-MON circuits between PCM harness
connector and generator harness connector. If both resistance measurements are less than 5 ohms, go to
next step. If either resistance measurement is 5 ohms or more, repair open in affected circuit.

8) Check GEN-MON Signal

Reconnect all connectors. Start engine and allow to idle. Using scan tool, access GFS PID from
PID/DATA MONITOR & RECORD menu. If GFS PID (duty cycle) is 3-95 percent (for LS and
Thunderbird) or 6-98 percent (all others), go to next step. If GFS PID (duty cycle) is not as specified,
replace generator/regulator assembly.

9) Check GEN-COM Signal

With engine idling, access ARC (Expedition & Navigator) or GENFDC (all others) PID from PID/DATA
MONITOR & RECORD menu. Observe ARC or GENFDC PID value, while cycling headlights on and
off. If ARC or GENFDC PID duty cycle reading switched within zero to 99 percent, fault is unable to be
duplicated at this time. Go to TEST Z, step 1). If ARC or GENFDC PID duty cycle reading did not
switch within zero to 99 percent, replace PCM.

10) Check Generator Charging Voltage
Start engine and allow to idle. Using DVOM, measure battery voltage. If the battery voltage is 12.2-14.7
volts, go to TEST Z, step 1). If the battery voltage is not 12.2-14.7 volts, replace generator/regulator
assembly.

TEST JB: SECONDARY IGNITION

NOTE:

Explorer/Mountaineer do not have diagnostic PIDS, and LS/Thunderbird
does not have a GENFDC PID.

NOTE:

After each service or repair procedure has been completed, reconnect all
components. Clear DTCs and repeat QUICK TEST procedures to ensure all EEC-
V systems are working properly and DTCs are no longer present.

2003 Ford Pickup F150

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

Diagnostic Aids

This test is intended to diagnose the following:

z

Spark Plugs

z

Spark Plug wires

Fig. 279: Coil Pack Spark Diagram
Courtesy of FORD MOTOR CO.

NOTE:

A malfunctioning ignition system may cause high catalyst temperatures. Check
components next to catalyst and muffler for heat damage.

2003 Ford Pickup F150

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