RELEASE under FUEL SYSTEMS in REMOVAL & INSTALLATION - F150 PICKUP - CNG article.
Close instruction lock-down valve jackscrew on forward in-bed fuel tank and mid fuel tank (if equipped)
solenoid valve. See Fig. 10. Tighten jackscrew(s) to 62-79 INCH lbs. (7-9 N.m). Open manual backflow
valve on fuel filler valve. Open manual bleed valve on fuel filler neck venting kit for 60 seconds, then
close bleed valve. Observe and record system pressure on fuel filler neck venting kit pressure gauge. If
pressure is zero psi (zero kPa), go to step 3. If pressure is more than zero psi (zero kPa), go to next step.
2. Check Rear In-Bed Fuel Tank Solenoid Valve Power Circuit For Short To Voltage
Ensure ignition is off. Disconnect rear in-bed fuel tank solenoid valve harness connector C4123. Using
DVOM, measure voltage between chassis ground and rear in-bed fuel tank solenoid valve harness
connector C4123 terminal No. 1 (Pink/Black wire). See Fig. 6. If voltage is more than 10 volts, repair
short to power in Pink/Black wire. See ENGINE PERFORMANCE in appropriate SYSTEM WIRING
DIAGRAMS article in ELECTRICAL. Retest system for normal operation and go to step
6
. If voltage is
10 volts or less, mark rear in-bed fuel tank solenoid valve as "Stuck Open". A NEW solenoid valve will
be installed after diagnostics are completed. Go to step 6.
3. Check Rear In-Bed Fuel Tank Solenoid Valve Operation
Turn ignition off. Reconnect rear in-bed fuel tank solenoid valve harness connector C4123. Connect scan
tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, enter OUTPUT TEST MODE.
Press "Start" button on scan tool to command all outputs on. Observe and record pressure on fuel filler
neck venting kit pressure gauge. Press "Stop" button on scan tool. If pressure reading was zero psi (zero
kPa) when "Start" button was pressed, go to next step. If pressure reading was more than zero psi (zero
kPa) when "Start" button was pressed, mark rear in-bed fuel tank solenoid valve as "Functions Normally",
then go to step 6.
4. Check Rear In-Bed Fuel Tank Solenoid Valve Power Circuit For An Open
Turn ignition off. Disconnect rear in-bed fuel tank solenoid valve harness connector C4123. Turn ignition
on. Using scan tool, enter OUTPUT TEST MODE. Press "Start" button on scan tool to command all
outputs on. Using DVOM, measure voltage between chassis ground and rear in-bed fuel tank solenoid
valve harness connector C4123 terminal No. 1 (Pink/Black wire). See Fig. 6. If voltage is more than 10
volts, go to next step. If voltage is 10 volts or less, repair open in Pink/Black wire. See ENGINE
PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Retest
system for normal operation and go to step 6.
5. Check Rear In-Bed Fuel Tank Solenoid Valve Ground Circuit For An Open
Turn ignition off. Using DVOM, measure resistance between chassis ground and rear in-bed fuel tank
solenoid valve wiring harness connector C4123 terminal No. 2 (Black wire). If resistance is less than 5
NOTE:
This procedure will supply power to fuel tank solenoid valve for
approximately 30-60 seconds. If time expires, cycle "Start/Stop" button on
scan tool to restore power.
NOTE:
This procedure will supply power to fuel tank solenoid valve for
approximately 30-60 seconds. If time expires, cycle "Start/Stop" button on
scan tool to restore power.
2003 Ford Pickup F150
2003 ENGINE PERFORMANCE System & Component Testing - CNG