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

Fig. 192: CHT Sensor Cold End & Hot End Line Graph
Courtesy of FORD MOTOR CO.

CHT SENSOR SPECIFICATIONS

(1)

COLD END or HOT END voltage at the same temperature. For example; at 194°F
(90°C), voltage could read either 0.60 volt or 3.71 volts. Refer to

CHT SENSOR

SPECIFICATIONS

table for temperature to voltage expected values.

Temperature °F (°C)

Volts

Ohms

-40 (-40)

4.89

965,808

-22 (-30)

4.81

513,019

-4 (-20)

4.67

283,664

14 (-10)

4.45

162,584

32 (0)

4.14

96,255

2003 Ford Pickup F150

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

50 (10)

3.73

59,175

68 (20)

3.26

37,387

86 (30)

2.74

24,215

104 (40)

2.23

16,043

122 (50)

1.76

10,850

140 (60)

1.36

7487

158 (70)

1.04

5268

176 (80)

(2)

.79 Or 3.99

3775

185 (85)

(2)

.69 Or 3.86

3215

194 (90)

(2)

.60 Or 3.71

2750

203 (95)

(2)

.53 Or 3.56

2361

212 (100)

(2)

.46 Or 3.41

2034

230 (110)

3.07

1523

248 (120)

2.74

1155

266 (130)

2.41

.887

284 (140)

2.10

689

302 (150)

1.81

542

320 (160)

1.55

430

338 (170)

1.33

345

356 (180)

1.13

279

374 (190)

.96

228

392 (200)

.82

188

410 (210)

.70

155

428 (220)

.60

130

446 (230)

.51

109

464 (240)

.44

92

482 (250)

.35

78

500 (260)

.33

67

(1)

Value may vary by 15 percent.

(2)

At this temperature, there is a voltage overlap zone due to a dual switching resistor circuit on CHT
input. It is possible to have either a cold end (low voltage) or hot end (high voltage) measurement at
the same temperature. Either voltage specification listed is correct.

2003 Ford Pickup F150

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

Fig. 193: Identifying CHT Sensor Harness Connector Terminals (Escape & Focus 2.0L 4V)
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

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