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Ford F150 Pickup. Instruction - part 1477
11) Check APP Sensor For Voltage Spikes During Operation
Connect PCM and APP sensor harness connectors. Turn ignition switch to ON position. Access and
monitor APP1, APP2 and APP3 PIDs. Depress accelerator pedal slowly and release. Do the PID'S display
a smooth voltage reading during the entire pedal travel (no voltage spikes)? If yes, go to next step. If no,
replace APP sensor.
12) Check APP Sensor For Intermittent Signal
Start engine and bring to idle. Run throttle up to 1500 RPM for 5 seconds. Access APP1 PID, and
monitor for a fault indication while completing the following: Lightly tap on he APP sensor, and wiggle
the harness connector to simulate road shock (repeat procedure for APP2 and APP3 PIDs). Are any of the
PID voltages below the minimum (.7 V), or above the maximum (4.6 V)? If yes, inspect APP sensor
harness connector. If connector is okay, replace APP sensor. If no, go to next step.
13) Check APP Sensor Harness For Intermittent Opens Or Shorts
Turn ignition switch to ON position, with engine off. Access APP1 PID, and monitor for a fault
indication while completing the following: Grasp the vehicle harness closest to the APP sensor connector.
Shake and bend a small section of the harness all the way from the dash panel to the PCM (repeat
procedure for APP2 and APP3 PIDs). Are any of the PID voltages below the minimum (.7 V), or above
the maximum (4.6 V)? If yes, isolate and repair as necessary. If no, unable to identify fault. Go to TEST
Z, step 1). If TEST Z does not identify fault, replace PCM.
TEST DL: CYLINDER HEAD TEMPERATURE SENSOR
Description
On vehicles that do not use an ECT sensor, a CHT sensor is used to determine engine coolant temperature in
place of ECT sensor. In this case, PCM may store both CHT and ECT DTCs. To cover entire temperature range
of both CHT and ECT sensors, PCM has a dual switching resistor circuit on CHT input. For a graph showing
temperature switching from COLD END line to HOT END line with increasing temperature and back with
decreasing temperature, see illustration. See Fig. 192.
Circuit
Closed Throttle Resistance (Ohms)
ETC REF To ETC RTN
1400-1500
APP1 To ETC RTN
4600-5000
APP2 To ETC RTN
2600-3000
APP3 To ETC RTN
2200-2600
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.
NOTE:
Within the temperature to voltage overlap zone, it is possible to have either a
2003 Ford Pickup F150
2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline