Ford F150 Pickup. Manual — part 1569

Fig. 336: Identifying Instrument Cluster Harness Connector C254
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

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

Fig. 337: Identifying Instrument Cluster Harness Connector C258
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

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

Fig. 338: Identifying Instrument Cluster Harness Connector C252
Courtesy of FORD MOTOR CO.

Testing

1) Check SIL Operation

Inspect SIL while driving vehicle. SIL should turn on when optimum shift RPM for each gear is reached.
SIL should turn off after shift is complete or while in top gear. If SIL is always illuminated, go to step 4).
If SIL does not illuminate, go to next step.

2) Check METER Fuse (10-Amp)

Remove METER fuse and inspect. If the fuse is okay, reinstall fuse and go to next step. If fuse is not
okay, repair short circuit as necessary. Replace SIL circuit fuse.

3) Check SIL Bulb

Remove SIL bulb and inspect. Using a DVOM, perform a continuity check if you suspect an open
filament and cannot determine the bulb's condition visually. If the SIL bulb is okay, go to step 5). If the
SIL bulb is not okay, replace SIL bulb.

2003 Ford Pickup F150

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

4) Check SIL Circuit For Short To Ground In Harness

Turn ignition switch to OFF position. Disconnect PCM. Using DVOM, measure resistance between the
SIL circuit at PCM harness connector and the battery negative terminal. If resistance is greater than 10
k/ohms, replace PCM. If resistance is not greater than 10 k/ohms, repair short circuit.

5) Check IGN Start/Run Voltage To SIL Socket

Turn ignition switch to OFF position. Remove SIL bulb. Turn ignition switch to ON position. Using a
DVOM, measure voltage of the SIL circuit between the SIL socket and chassis ground. If the voltage
greater than 10.5 volts, turn ignition switch to OFF position and go to step 8). If the voltage is 10.5 volts
or less, repair open SIL circuit.

8) Check SIL Circuit For Open In Harness

Turn ignition switch to OFF position. Disconnect PCM. Using a DVOM, measure resistance between SIL
circuit at PCM harness connector and SIL bulb socket. If resistance is less than 5 ohms, replace PCM. If
resistance is 5 ohms or greater, repair open circuit.

TEST KM: A/C CLUTCH RELAY & A/C CIRCUITS

Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used
to diagnose the following:

z

Wiring Harness Circuits (ACCS, ACPSW, VPWR & WAC). See Fig. 339-Fig. 349

z

Faulty A/C clutch Relay

z

Faulty Powertrain Control Module (PCM)

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips
from step 5) to step 8). No test procedures have been omitted.

NOTE:

A/C relay or A/C clutch relay may also be referred to as Wide Open Throttle A/C
Cut-Off (WAC) relay.

NOTE:

After each service or repair procedure has been completed, reconnect all
components. Clear DTCs. Start engine and allow to idle. Turn A/C on and wait
15 seconds. Turn A/C off, then turn ignition switch to OFF position. 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