Ford F150 Pickup. Manual - part 1474

7) Check TP Sensor Voltage To PCM 
 
Reconnect PCM and TP sensor harness connector(s). Start engine and idle for 2 minutes. Using scan tool, 
access TP and (TP V) PID from PID/DATA MONITOR & RECORD menu. While observing TP and TP 
V PID, slowly open throttle. If at any time TP or (TP V) PID readings fall between 3.42-9.85 percent 
(.17-.49 volt), replace TP sensor. If TP or (TP V) PID readings do not fall between 3.42-9.85 percent 
(.17-.49 volt), repeat QUICK TEST. If DTC P1120 is still present, go to step 20). 

8) For KOEO, KOER & Continuous Memory DTC P0123: Attempt To Generate Opposite TP 
Angle (Voltage) PID Reading 
This DTC indicates TP sensor rotation angle or voltage exceeded maximum calibrated limit during 
KOEO or KOER self-test. Possible causes for this fault are: 

z

TP Sensor Not Seated Fully  

z

TP Circuit Shorted To VPWR  

z

VREF Circuit Shorted To VPWR  

z

SIG RTN Circuit Open To TP Sensor  

z

Faulty TP Sensor  

z

Faulty PCM  

Turn ignition switch to OFF position. Disconnect TP sensor connector. Inspect connector for loose, 
damaged or corroded terminals and repair as necessary. Turn ignition switch to ON position. Using scan 
tool, access TP and TP V PID from PID/DATA MONITOR & RECORD menu. If TP or (TP V) PID 
readings are not less than 3.42 percent (.17 volt) or more, go to step 10). If TP or (TP V) PID readings are 
less than 3.42 percent (.17 volt), go to next step. 

9) Check Voltage Between VREF & SIG RTN Circuits At TP Sensor 
 
Using a DVOM, measure voltage between VREF and SIG RTN circuits at TP sensor harness connector. 
See Fig. 163, Fig. 165 and Fig. 166 . If voltage is 4-6 volts, replace TP sensor. If voltage is not 4-6 volts, 
reconnect components and go to TEST C, step 1). 

10) Check TP Circuit For Short To VREF Or VPWR Circuits 
 
Turn ignition switch to OFF position. Leave TP sensor disconnected. Disconnect PCM connector(s). 
Inspect connector for loose, damaged or corroded terminals and repair as necessary. Using a DVOM, 
measure resistance between TP circuit, VPWR and VREF circuits at PCM harness connector. Both VREF 
circuits on 150-pin PCM models. If any resistance measurement is 10 k/ohms or less, repair short 
between circuits. If all resistance measurements are more than 10 k/ohms, replace PCM. 

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

An intermittent fault can cause a Continuous Memory DTC P0122. If a 

 

2003 Ford Pickup F150 

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

  

11) For KOEO, KOER & Continuous Memory DTC P0122: Attempt To Generate Opposite TP 
Angle (Voltage) PID Reading 
This DTC indicates TP sensor rotation angle or voltage fell below minimum calibrated limit during 
KOEO or KOER self-test. Possible causes for this fault are: 

z

TP Sensor Not Seated Fully  

z

TP Circuit Open To PCM  

z

VREF Circuit Open To TP Sensor  

z

TP Circuit Shorted To SIG RTN Or GND  

z

Faulty TP Sensor  

z

Faulty PCM  

Turn ignition switch to OFF position. Disconnect TP sensor connector. Inspect connector for loose, 
damaged or corroded terminals and repair as necessary. Connect a jumper wire between VREF and TP 
circuits at TP sensor harness connector. Turn ignition switch to ON position. 

Using scan tool, access TP and (TP V) PID from PID/DATA MONITOR & RECORD menu. If TP or 
(TP V) PID readings are more than 9.3 percent (4.65 volts), replace TP sensor. If TP or (TP V) PID 
readings are 9.3 percent (4.65 volts) or less, remove jumper wire and go to next step. 

12) Check Voltage Between VREF & SIG RTN Circuits 
 
Turn ignition switch to ON position. Using a DVOM, measure voltage between VREF and SIG RTN 
circuits at TP sensor harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, 
reconnect sensor and go to TEST C, step 1). 

13) Check TP Circuit For Open In Harness 
 
Turn ignition switch to OFF position. Leave TP sensor disconnected. Disconnect PCM connector(s). 
Inspect connector for loose, damaged or corroded terminals and repair as necessary. Using a DVOM, 
measure resistance of TP circuit between PCM harness connector and TP sensor harness connector. See 
Fig. 163, Fig. 165 and Fig. 166 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms 
or more, repair open in TP circuit. 

14) Check TP Circuit For Short To SIG RTN Or PWR GND In Harness 
 
Ensure PCM is disconnected. Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, 
measure resistance between TP circuit, and SIG RTN and PWR GND circuits at PCM harness connector. 
If either resistance measurement is 10 k/ohms or less, repair short between circuits. If both resistance 
measurements are more than 10 k/ohms, replace PCM. 

Continuous Memory DTC P0122 is still present after performing steps 11)-
14) , go to TEST Z, step 1) for intermittent testing.

NOTE:

If a scan tool communication concern exists, remove jumper wire and go 
to step 14).

 

2003 Ford Pickup F150 

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

  

15) For KOER & Continuous Memory Only DTCs P0068 & P1121: Check Rationality Operation 
Between TP & MAF Sensors 
This DTC is set when the comparison between TP and MAF sensor readings are not consistent with 
calibrated load values during KOER self-test. Possible causes for this fault are: 

z

Air Leak Between MAF Sensor & Throttle Body  

z

TP Sensor Not Seated Fully  

z

Faulty TP Sensor  

z

Faulty MAF Sensor  

Attempt to start engine. If engine starts, go to next step. If engine does not start, check for cracks or 
openings in air induction system between MAF sensor and throttle body. Repair as necessary. If air 
induction system is okay, go to TEST A, step 1). 

16) Check Mechanical Operation Of TP Sensor 
 
Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition 
switch to ON position. Using scan tool, access TP and (TP V) PID from PID/DATA MONITOR & 
RECORD menu. While observing TP and (TP V) PID readings, slowly move throttle from closed 
position to wide open throttle position. If TP or (TP V) PID readings change from 9.85-93.00 percent 
(.49-4.65 volts), go to next step. If TP or (TP V) PID readings do not change from 9.85-93.00 percent 
(.49-4.65 volts), replace TP sensor. Repeat QUICK TEST to verify repair. 

17) Check TP Sensor Signal High Versus Engine Load While Driving Vehicle 
 
Drive vehicle (vary throttle position) while selecting TP, (TP V) and LOAD PIDs from PID/DATA 
MONITOR & RECORD menu. If TP or (TP V) PID readings are 49.02 percent (2.44 volts) or less, and 
LOAD PID reading is 30 percent or more, go to next step. If TP or (TP V) PID readings are more than 
49.02 percent (2.44 volts), and LOAD PID value is less than 30 percent, check for cracks or openings in 
air induction system between MAF sensor and throttle body. If air induction is restricted, go to TEST 
HU, step 1) and repair as necessary. If air induction system is okay, replace TP sensor. 

18) Check TP Sensor Signal Low Versus Engine Load While Driving Vehicle 
 
Start engine and allow to idle. If engine is a no-start, go to TEST A, step 1). Drive vehicle (vary throttle 
position) in higher gears (preferably Overdrive) while selecting TP, TP V and LOAD PID from 
PID/DATA MONITOR & RECORD menu. If TP or (TP V) PIDs are 4.82 percent (.24 volt) or more, and 
LOAD PID is 55 percent or less, fault is intermittent and cannot be duplicated at this time. Testing is 
complete. If TP or (TP V) PIDs are less than 4.82 percent (.24 volt), and LOAD PID is more than 55 
percent, tighten TP sensor (if necessary). Clear DTCs. Road test vehicle ensuring throttle is operated 
through all phases. Perform QUICK TEST. If Continuous Memory DTC P1121 is still present, replace 
MAF sensor. 

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 

 

2003 Ford Pickup F150 

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

  

20) For Continuous Memory Only DTC P1125: Check For Intermittent TP Circuit Signal 
These DTCs are set when TP sensor voltage reading falls below minimum calibrated range of .49 volt or 
exceeds maximum calibrated range of 4.65 volts during the last 80 drive cycles. Possible causes for this 
fault are: 

z

Poor Continuity Through TP Sensor Wiring Harness Or Connector  

z

Intermittent Open Or Short In TP Sensor  

Ensure scan tool is connected to Data Link Connector (DLC). Start engine and allow to idle. Raise engine 
speed to 1500 RPM for 5 seconds and return to idle. Using scan tool, access TP and TP V PID from 
PID/DATA MONITOR & RECORD menu. While observing TP and TP V PID, lightly tap on TP sensor 
and wiggle sensor connector and wiring harness to simulate road shock. If TP or (TP V) PID readings 
stay within normal operating range of 9.85-93.00 percent (.49-4.65 volts), go to next step. If TP or (TP V) 
PID readings do not stay within normal operating range of 9.85-93.00 percent (.49-4.65 volts), inspect TP 
sensor installation and connector. Repair as necessary and retest. If TP sensor installation and connector 
are okay, replace TP sensor. 

21) Check TP Sensor Harness For Intermittent Opens Or Shorts 
 
Turn ignition switch to OFF position. Using scan tool, access TP and TP V PIDs from PID/DATA 
MONITOR & RECORD menu. Turn ignition switch to ON position. While observing TP and TP V PIDs, 
wiggle small sections of wiring harness starting at TP sensor working toward PCM. If TP or (TP V) PID 
readings stay within normal operating range of 9.85-93.00 percent (.49-4.65 volts), concern is intermittent 
and cannot be identified at this time. Go to TEST Z, step 1). If TP or (TP V) PID readings do not stay 
within normal operating range of 9.85-93.00 percent (.49-4.65 volts), isolate fault and repair as necessary. 

22) For KOER & Continuous Memory Only DTC P0121: Isolate Binding Or Sticking Concern 
Disconnect accelerator and speed control cables from throttle body linkage. Rotate linkage on throttle 
body. If sticking, binding or grabbing is felt when rotating throttle body linkage, replace throttle body 
assembly. If throttle body linkage rotates freely without sticking, binding or grabbing, replace faulty cable
(s). Repeat QUICK TEST. If DTC P0121 is still present, go to next step. 

23) Check Functionality Of TP Sensor 
 
Turn ignition switch to ON position. Using scan tool, access TP V PID from PID/DATA MONITOR & 
RECORD menu. While observing TP V PID voltage, slowly move throttle through range from closed 
position to wide open throttle. If TP V PID voltage increases smoothly during throttle movement, concern 

from step 18) to step 20). No test procedures have been omitted.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

NOTE:

For additional testing information, see DIAGNOSTIC AIDS.

CAUTION: DO NOT clean throttle bore or plate area. Cleaning will damage 

throttle body assembly.

 

2003 Ford Pickup F150 

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