Ford F150 Pickup. Instruction - part 1482

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Short to GND in VSS harness circuit.  

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Short to GND in TCSS harness circuit.  

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Short to PWR in VSS harness circuit.  

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Short to PWR in TCSS harness circuit.  

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Open or short in the vehicle speed circuit(s) (VSC) between the PCM and appropriate control 
module.  

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Damaged VSS or TCSS.  

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Damaged wheel speed sensors.  

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Damaged wheel speed sensor harness circuits.  

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Damage in module(s) connected to VSC/VSS circuit.  

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Damage drive mechanism for VSS or TCSS.  

TCSS provides rotational speed of transfer case output shaft. PCM uses this signal to control powertrain 
behavior and on some models is used as source of vehicle speed information. Disconnect TCSS 
connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. If connector 
terminals are okay, go to next step. 

31) Check Resistance Of TCSS 
 
Using a DVOM, measure resistance between TCSS SIG and TCSS SIG RTN circuits at TCSS connector. 
See Fig. 200 or Fig. 201 . If resistance is 1000-1250 ohms, go to next step. If resistance is not 1000-1250 
ohms, replace TCSS. 

Fig. 200: Identifying TCSS Circuits & Connector Terminals (Pickup 4.2L 4WD With Instruction Shift-
On-The-Fly) 
Courtesy of FORD MOTOR CO. 

 

2003 Ford Pickup F150 

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

  

Fig. 201: Identifying TCSS Circuits & Connector Terminals (Pickup 4.6/5.4L 4WD With Instruction 
Shift-On-The-Fly) 
Courtesy of FORD MOTOR CO. 

32) TCSS Output Check 
 
Road test vehicle and measure frequency between TCSS SIG and TCSS SIG RTN circuits at TCSS 
connector. Drive vehicle between zero and 30 MPH. Compare TCSS frequency to the frequency listed in 
appropriate PIN VOLTAGE/PID VALUE - INPUTS chart in appropriate PIN VOLTAGE/PID VALUE 
CHARTS article. Ensure frequency increases and decreases with vehicle speed. If frequency is as 
specified, go to next step. If frequency is not as specified, remove TCSS from transfer case. Inspect TCSS 
target wheel and repair as necessary. If TCSS target wheel is okay, replace TCSS. 

33) Check Harness For Short To PWR 
 
Turn ignition switch to ON position. Disconnect TCSS connector. Using a DVOM, measure voltage 
between chassis ground and TCSS SIG circuit at TCSS harness connector. See Fig. 200 or Fig. 201 . If 
voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR. 

34) Check Harness For Open 
 

 

2003 Ford Pickup F150 

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

  

Turn ignition switch to OFF position. Disconnect PCM connector. Using a DVOM, measure resistance of 
TCSS SIG and TCSS SIG RTN circuits between TCSS harness connector and PCM harness connector. 
See Fig. 200 or Fig. 201 . If both resistance measurements are less than 5 ohms, go to next step. If either 
resistance measurement is 5 ohms or more, repair open in affected circuit. 

35) Check Harness For Short To Ground 
 
Using a DVOM, measure resistance between TCSS SIG circuit, TCSS SIG RTN circuit and chassis 
ground at TCSS harness connector. See Fig. 200 or Fig. 201 . If both resistance measurements are more 
than 10 k/ohms, replace PCM. If either resistance measurement is 10 k/ohms or less, repair short to 
ground in TCSS SIG circuit.  

TEST DQ: BAROMETRIC PRESSURE SENSOR 

Diagnostic Aids 

Perform this test when directed by QUICK TEST. This system test is intended to diagnose:  

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Barometric Pressure (BARO) Sensor  

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Wiring Harness Circuits (BARO SIG, SIG RTN & VREF)  

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Powertrain Control Module (PCM)  

VREF voltage should be 4-6 volts. BARO PID reading is in frequency/volts. 

Fig. 202: Identifying BARO Sensor Circuits & Connector Terminals

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.

 

2003 Ford Pickup F150 

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

  

Courtesy of FORD MOTOR CO. 

BARO SENSOR SPECIFICATIONS 

Testing 

1) For KOEO, KOER & Continuous Memory DTC P0106, P0107, P0108 Or P0109: Check BARO 
PID 
DTC P0106 indicates BARO sensor reference voltage is not within calibrated limit of 4-6 volts. DTC 
P0107 indicates BARO sensor reference voltage fell below calibrated limit of .25 volt. DTC P0108 
indicates BARO sensor reference voltage exceeded calibrated limit of 5 volts. DTC P0109 indicates 
intermittent BARO sensor signal failure. Possible causes for these faults are: 

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VREF Circuit Open, Shorted To Ground Or VPWR  

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BARO Signal Shorted To VPWR  

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Faulty BARO Sensor  

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Faulty PCM  

Ensure BARO sensor is connected properly. Obtain local barometric pressure measurement. Turn ignition 
switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON 
position. Using scan tool, access BARO PID from PID/DATA MONITOR & RECORD menu. Compare 

In. Hg (kPa)

Frequency (Volts)

Altitude Above Sea Level (Feet)

3.5 (11.8)

0.15

N/A

5 (16.9)

0.40

N/A

10 (33.8)

1.25

N/A

15 (50.7)

2.10

14,000

20 (67.5)

2.90

10,000

21 (70.9)

3.10

9000

22 (74.3)

3.30

8000

23 (77.7)

3.50

7000

24 (81.1)

3.62

6000

25 (84.4)

3.80

5000

26 (87.8)

4.00

4000

27 (91.2)

4.14

3000

28 (94.6)

4.30

2000

29 (97.9)

4.50

1000

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

If local barometric pressure is not corrected to sea level or cannot be 
obtained, check a known good vehicle BARO sensor PID value to 
determine actual barometric pressure. Local weather conditions (high or 
low pressure areas) will change local barometric pressure by several 
inches of mercury plus or minus 0.9 volt (plus or minus 2 in. Hg).

 

2003 Ford Pickup F150 

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