Ford F150 Pickup. Instruction - part 1568

Fig. 334: Supercharger System Vacuum Diagram
Courtesy of FORD MOTOR CO.

Fig. 335: Identifying Supercharger (Boost) By-Pass Solenoid Wiring Harness Connector Terminals
Courtesy of FORD MOTOR CO.

Testing

1) KOEO, KOER & Continuous Memory DTC P0234: Check For Other DTCs
DTC P0234 is set and PCM disables supercharger boost to keep from damaging engine or transmission
during potentially harmful operating conditions. Possible causes are.

Brake Torque Condition (Brake Pedal Applied & Throttle At Wide Open Position)

Transmission Oil Temperature Exceeds Calibrated Threshold

Engine Overheating

Ignition Misfire Exceeding Calibrated Threshold

Knock Sensor Failure Or Knock Detected

Low Speed Fuel Pump Relay Not Switching

If engine is a no-start, go to TEST A, step 1). If engine starts and then stalls, diagnose by symptom. Go to
SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article. If
engine starts and does not stall, road test vehicle 10-15 minutes with engine speed exceeding 2000 RPM.
Ensure engine is at normal operating temperature and that upper radiator hose is hot and pressurized.
Repeat QUICK TEST and check for KOEO, KOER and Continuous Memory DTCs. If any other DTCs
are present with DTC P0234, service other DTCs before continuing with this test. See DIAGNOSTIC
TROUBLE CODE DEFINITIONS. If only DTC P0234 is present, go to next step.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

Supercharger is by-passed when brakes are applied and throttle is in wide
open position. This condition causes excessive engine torque and is
referred to as brake torque. If possible, check with vehicle owner to
determine if engine has been subjected to a brake torque condition
causing DTC P0234 to set.

2003 Ford Pickup F150

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

2) Check Scan Tool PIDs For Causes Of Overboost Condition

Start engine and allow to idle. Using scan tool, access IAT2, TFT and RPM PIDs from PID/DATA
MONITOR & RECORD menu. If IAT2 PID value is more than 230°F (110°C), check for low fluid level
in intercooler system. Check for cracked intercooler lines. Repair as necessary. If TFT PID value (5.4L
SC only) is more than 275°F (135°C), check for low transmission fluid level. Check for transmission
leaks. Repair as necessary. If IAT2 PID value is 230°F (110°C) or less and TFT PID value is 275°F (135°
C) or less, go to next step.

3) Check For Low Speed Fuel Pump Relay Not Switching

Start engine and allow to idle. Using scan tool, access LFPF PID from PID/DATA MONITOR &
RECORD menu. If LFPF PID value indicates YES (fault present), go to TEST KA, step 45) and/or 60)
and perform diagnostics for DTC P1232. If LFPF PID value indicates NO (no fault present), cause of
overboost condition is unable to be determined at this time. Check for engine knock while driving
vehicle. Repair as necessary. If engine knock is not present, ensure vehicle owner has an understanding of
a brake torque condition and that brake torque can result in transmission damage.

6) For KOEO, KOER & Continuous Memory DTC P0243: Check Supercharger (Boost) By-Pass
Solenoid Output
DTC P0243 is set when PCM detects Supercharger By-pass (SCB) solenoid circuit signal exceeds
minimum or maximum allowable calibrated parameters for a specified SCB solenoid duty cycle (100
percent or zero percent). Possible causes are:

VPWR Circuit Open To SCB Solenoid

SCB Solenoid Circuit Open, Or Shorted To PWR GND Or CHASSIS GND, Or VPWR

Faulty SCB solenoid

Faulty PCM

Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Disconnect SCB
solenoid connector. Connect a test light between SCB and VPWR circuits at SCB solenoid harness
connector. See Fig. 335. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST
MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Attempt to close
and open SCB solenoid driver in PCM by commanding ALL OUTPUTS ON and then OFF. Observe test
light while cycling ALL OUTPUTS ON, then OFF. If test light illuminates then turns off, go to next step.
If test light remains off, go to step 8). If test light remains illuminated, go to step 11).

7) Check SCB Solenoid Resistance

Turn ignition switch to OFF position. Using a DVOM, measure resistance between SCB solenoid
terminals. If resistance is not 68-78 ohms, replace SCB solenoid. If resistance is 68-78 ohms, check for

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 3) to step 6). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

2003 Ford Pickup F150

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

damaged vacuum hoses between intake manifold and SCB solenoid. Check for vacuum reservoir leaks.
Repair or replace as necessary. If no faults are found, check for intermittent faults. Go to TEST Z, step 1).

8) Check For Open VPWR Circuit Between SCB Solenoid & PCM Power Relay

Using a DVOM, measure voltage between negative battery terminal and SCB solenoid harness connector
VPWR terminal. See Fig. 335. If voltage is more than 10.5 volts, go to step 10). If voltage is 10.5 volts or
less, go to next step.

9) Check VPWR Circuit For Open In Harness

Turn ignition switch to OFF position. Disconnect PCM connector. Inspect connector for loose, damaged
or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of VPWR circuit
between PCM harness connector and SCB solenoid harness connector. See PCM CONNECTOR
IDENTIFICATION and Fig. 335. If resistance is less than 5 ohms, go to next step. If resistance is 5
ohms or more, repair open in VPWR circuit.

10) Check SCB Circuit For Open In Harness

Using a DVOM, measure resistance of SCB circuit between PCM harness connector and SCB solenoid
harness connector. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair
open in SCB circuit.

11) Check SCB Circuit For Short To PWR GND In Harness

Turn ignition switch to OFF position. Disconnect scan tool from DLC. Disconnect PCM connector.
Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM,
measure resistance between SCB circuit and PWR GND circuits at PCM harness connector. See PCM
CONNECTOR IDENTIFICATION and Fig. 335. See PCM PWR GND, SIG RTN & VREF
TERMINAL IDENTIFICATION table. If all resistance measurements are more than 10 k/ohms, go to
next step. If any resistance measurement is 10 k/ohms or less, repair short to PWR GND in SCB circuit.
See WIRING DIAGRAMS.

12) Check SCB Circuit For Short To PWR Or Chassis Ground In Harness

Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and SCB
circuit at PCM harness connector. If voltage is less than one volt, replace PCM. If voltage is one volt or
more, repair SCB circuit for short to VPWR, VREF or chassis ground. See WIRING DIAGRAMS.

13) Lack Of Power (Low Boost): Check Vacuum Hoses
Check vacuum hoses for cracks, bends, kinks, leaks or being disconnected between the following areas:

Supercharger by-pass actuator and supercharger by-pass solenoid.

NOTE:

Step 13) is performed when directed here from LACK/LOSS OF POWER
symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG,
FLEX-FUEL & GASOLINE article.

2003 Ford Pickup F150

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

Supercharger by-pass solenoid and vacuum reservoir assembly.

Repair or replace component(s) as necessary. If no concerns are found, return to LACK/LOSS OF
POWER symptom diagnosis under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG &
GASOLINE article.

TEST KL: SHIFT INDICATOR LIGHT

Diagnostic Aids

Perform this test only when directed here by a driveability symptom. This test is only intended to diagnose:

Shift Indicator Light (SIL) Bulb & Instrument Cluster

METER Fuse & VPWR Circuit To Instrument Cluster

Wiring Harness Circuit; (SIL)

Powertrain Control Module (PCM)

NOTE:

SYSTEM TEST KL is performed when directed here from SYMPTOMS in
TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article.

NOTE:

This system test is for ZX2 M/T only.

2003 Ford Pickup F150

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

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