Test Procedure
- DK1 CHECK FOR DTCS
Are DTCs P2104, P2121, P2122, P2123, P2126, P2127, P2128, P2131, P2132, or P2133 present?
Yes No GO to DK2. For a lack/loss of power, GO to DK2.
For all others, GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS . - DK2 CHECK THE ACCELERATOR PEDAL FOR OBSTRUCTION
- Key ON, engine OFF.
- Press the accelerator pedal fully to the floor and release.
Does the pedal move freely to the floor and back?
Yes No GO to DK3. ISOLATE and REPAIR the obstruction.
CLEAR the DTCs. REPEAT the self-test. - DK3 CHECK THE APP SENSOR SIGNAL VOLTAGE RANGES FOR THE ACCELERATOR PEDAL FULLY APPLIED AND RELEASED POSITIONS
- Access the PCM and monitor the APPS1, APPS2 and APPS3 PIDs.
- Press the accelerator pedal fully to the floor and release.
ACCELERATOR PEDAL FULLY APPLIED VOLTAGE VALUESVehicle APPS1 APPS2 APPS3 Fusion, Milan, Zephyr 1.20 - 2.50 2.50 - 3.94 2.00 - 3.33 LS 0.50 - 1.44 3.15 - 4.60 2.66 - 3.99 Explorer, Mountaineer 0.60 - 1.57 3.07 - 4.50 2.57 - 3.89 Expedition, Navigator 0.79 - 2.09 2.75 - 4.33 2.26 - 3.73 F-150, Mark LT 0.60 - 1.57 3.07 - 4.50 2.57 - 3.89 E-Series 0.73 - 1.28 3.03 - 4.55 2.59 - 3.89 F-Super Duty 0.39 - 0.97 3.45 - 4.71 2.95 - 4.10 All others 0.48 - 1.76 2.95 - 4.62 2.43 - 4.02 ACCELERATOR PEDAL FULLY RELEASED VOLTAGE VALUESVehicle APPS1 APPS2 APPS3 All vehicles 3.43 - 4.69 1.13 - 1.88 0.64 - 1.28 Are all 3 APPS signals out of range for the pedal fully applied and released positions?
Yes No GO to DK4. For DTCs P2104, P2121, P2122, P2123, P2126, P2127, P2128, P2131, P2132 or P2133 alone, GO to DK8.
For any combination of ETC related DTCs, GO to DK4.
For continuous memory DTCs P2121 and P2126 with P2131, GO to DK22.
For a lack/loss of power, GO to DK8. - DK4 CHECK THE VREF VOLTAGE TO APP SENSOR
- Key in OFF position.
- APP Sensor connector disconnected.
- Key ON, engine OFF.
- Measure the voltage between:
( + ) APP Sensor Connector, Harness Side ( - ) APP Sensor Connector, Harness Side ETCREF ETCRTN
Is the voltage between 4 - 6 V?
Yes No GO to DK5. GO to Pinpoint Test C . - DK5 CHECK THE FUNCTIONALITY OF THE APPS1 CIRCUIT NOTE: Use the voltage measurements from DK3.
Is APPS1 out of range?
Yes No GO to DK8. GO to DK6. - DK6 CHECK THE FUNCTIONALITY OF APPS2 NOTE: Use the voltage measurements from DK3.
Is APPS2 out of range?
Yes No GO to DK8. GO to DK7. - DK7 CHECK THE FUNCTIONALITY OF APPS3 NOTE: Use the voltage measurements from DK3.
Is APPS3 out of range?
Yes No GO to DK8. GO to DK22. - DK8 CHECK THE FUNCTIONALITY OF THE APP SENSOR
- Key in OFF position.
- APP Sensor connector disconnected.
- Measure the resistance between:
- For E-Series, Explorer, F-150, F-Super Duty, LS, Mark LT, Mountaineer:APP RESISTANCE SPECIFICATION (FOR E-SERIES, EXPLORER, F-150, F-SUPER DUTY, LS, MARK LT, MOUNTAINEER)
(+) APP Sensor Connector, Component Side (-) APP Sensor Connector, Component Side Minimum Resistance (ohms) Maximum Resistance (ohms) APPS1 ETCREF 400 1,300 APPS1 ETCRTN 900 2,300 APPS1 APPS2 2,000 4,800 APPS1 APPS3 2,000 4,800 APPS2 ETCREF 1,700 4,100 APPS2 ETCRTN 1,400 3,500 APPS2 APPS3 2,700 6,500 APPS3 ETCREF 1,700 4,100 APPS3 ETCRTN 1,300 3,200 ETCREF ETCRTN 700 1,700 - For Fusion, Milan, and Zephyr:APP RESISTANCE SPECIFICATION (FOR FUSION, MILAN, AND ZEPHYR)
(+) APP Sensor Connector, Component Side (-) APP Sensor Connector, Component Side Minimum Resistance (ohms) Maximum Resistance (ohms) APPS1 ETCREF 650 1,340 APPS1 ETCRTN 1,210 2,470 APPS1 APPS2 2,430 4,960 APPS1 APPS3 2,390 4,880 APPS2 ETCREF 2,020 4,120 APPS2 ETCRTN 1,650 3,380 APPS2 APPS3 3,000 6,130 APPS3 ETCREF 2,010 4,110 APPS3 ETCRTN 1,450 2,970 ETCREF ETCRTN 900 1,840 - For all other vehicles with a 7-pin APP sensor:APP RESISTANCE SPECIFICATION (FOR ALL OTHER VEHICLES WITH 7-PIN APP SENSOR)
(+) APP Sensor Connector, Component Side (-) APP Sensor Connector, Component Side Minimum Resistance (ohms) Maximum Resistance (ohms) APPS1 ETCREF 600 1,370 APPS1 ETCRTN 720 1,660 APPS1 APPS2 1,300 2,960 APPS1 APPS3 1,250 2,860 APPS2 ETCREF 750 1,720 APPS2 ETCRTN 660 1,520 APPS2 APPS3 1,230 2,810 APPS3 ETCREF 710 1,640 APPS3 ETCRTN 580 1,340 ETCREF ETCRTN 200 470 - For all other vehicles with an 8-pin APP sensor:APP RESISTANCE SPECIFICATION (FOR ALL OTHER VEHICLES WITH 8-PIN APP SENSOR)
(+) APP Sensor Connector, Component Side (-) APP Sensor Connector, Component Side Minimum Resistance (ohms) Maximum Resistance (ohms) APPS1 ETCREF 150 350 APPS1 ETCRTN 290 650 APPS1 APPS2 900 2,010 APPS1 APPS3 820 1,840 APPS2 ETCREF 800 1,790 APPS2 ETCRTN 700 1,580 APPS2 APPS3 1,270 2,860 APPS3 ETCREF 720 1,630 APPS3 ETCRTN 580 1,330 ETCREF ETCRTN 210 470
Are all the resistances within specifications?
Yes No For DTCs P2121, P2122 or P2123 alone or in combination, GO to DK10.
For DTCs P2126, P2127 or P2128 alone or in combination, GO to DK14.
For DTCs P2131, P2132 or P2133 alone or in combination, GO to DK18.
For DTC P2104 alone, GO to DK26.
For a lack/loss of power, the concern is elsewhere. RETURN to SYMPTOM CHARTS for further direction.
For all others, GO to DK22.INSTALL a new APP sensor. REFER to the appropriate ACCELERATION CONTROL article .
CLEAR the DTCs.
PRESS the accelerator pedal several times and REPEAT the self-test. If DTCs are present:
GO to DK9. - DK9 CHECK THE APP SENSOR CIRCUIT INTEGRITY
- Key in OFF position.
- APP Sensor connector disconnected.
- Measure the resistance between:
( + ) APP Sensor Connector, Component Side ( - ) APP Sensor Connector, Component Side ETCREF ETCRTN
Is the resistance between 700 ohms - 1,700 ohms (E-Series, Explorer, F-150, F-Super Duty, LS, Mark LT, Mountaineer), 900 ohms - 1,840 ohms (Fusion, Milan, Zephyr), 200 ohms - 470 ohms (all other vehicles with a 7-pin APP sensor), or 210 ohms - 470 ohms (all other vehicles with an 8-pin APP sensor)?
Yes No For continuous memory DTCs P2121 with P2122 or P2123, or with P2126 and P2131, GO to DK10.
For continuous memory DTCs P2126 with P2127 or P2128, or with P2121 and P2131, GO to DK14.
For continuous memory DTCs P2121 and P2122 or P2131 and P2133, GO to DK18.INSTALL a new APP sensor. REFER to the appropriate ACCELERATION CONTROL article .
CLEAR the DTCs.
PRESS the accelerator pedal several times and REPEAT the self-test. If DTCs are present:
GO to DK10. - DK10 CHECK THE APPS1 CIRCUIT FOR AN OPEN IN THE HARNESS
- PCM connector disconnected.
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) PCM Connector, Harness Side APPS1 APPS1
Is the resistance less than 5 ohms?
Yes No GO to DK11. REPAIR the open circuit. CLEAR the DTCs.
REPEAT the self-test. - DK11 CHECK THE APPS1 CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) 12 Volt Vehicle Battery APPS1 Negative terminal
Is the resistance greater than 10K ohms?
Yes No GO to DK12. REPAIR the short circuit to GND. CLEAR the DTCs. REPEAT the self-test. - Measure the resistance between:
- DK12 CHECK THE APPS1 CIRCUIT FOR A SHORT IN THE HARNESS
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) APP Sensor Connector, Harness Side APPS1 ETCRTN APPS1 ETCREF
Are the resistances greater than 10K ohms?
Yes No GO to DK13. REPAIR the short circuit. CLEAR the DTCs.
REPEAT the self-test. - Measure the resistance between:
- DK13 CHECK THE APPS1 CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
- Key ON, engine OFF.
- Measure the voltage between:
( + ) APP Sensor Connector, Harness Side ( - ) 12 Volt Vehicle Battery APPS1 Negative terminal
Is any voltage present?
Yes No REPAIR the short circuit. CLEAR the DTCs.
REPEAT the self-test.GO to DK22. - DK14 CHECK THE APPS2 CIRCUIT FOR AN OPEN IN THE HARNESS
- PCM connector disconnected.
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) PCM Connector, Harness Side APPS2 APPS2
Is the resistance less than 5 ohms?
Yes No GO to DK15. REPAIR the open circuit. CLEAR the DTCs.
REPEAT the self-test. - DK15 CHECK THE APPS2 CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS
- Measure the resistance between:
( + ) PCM Connector, Harness Side ( - ) 12 Volt Vehicle Battery APPS2 Negative terminal
Is the resistance greater than 10K ohms?
Yes No GO to DK16. REPAIR the short circuit to GND. CLEAR the DTCs. REPEAT the self-test. - Measure the resistance between:
- DK16 CHECK THE APPS2 CIRCUIT FOR A SHORT IN THE HARNESS
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) APP Sensor Connector, Harness Side APPS2 ETCRTN APPS2 ETCREF
Are the resistances greater than 10K ohms?
Yes No GO to DK17. REPAIR the short circuit. CLEAR the DTCs.
REPEAT the self-test. - Measure the resistance between:
- DK17 CHECK THE APPS2 CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
- Key ON, engine OFF.
- Measure the voltage between:
( + ) PCM Connector, Harness Side ( - ) 12 Volt Vehicle Battery APPS2 Negative terminal
Is any voltage present?
Yes No REPAIR the short circuit. CLEAR the DTCs.
REPEAT the self-test.GO to DK23. - DK18 CHECK THE APPS3 CIRCUIT FOR AN OPEN IN THE HARNESS
- PCM connector disconnected.
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) PCM Connector, Harness Side APPS3 APPS3
Is the resistance less than 5 ohms?
Yes No GO to DK19. REPAIR the open circuit. CLEAR the DTCs.
REPEAT the self-test. - DK19 CHECK THE APPS3 CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS
- Measure the resistance between:
( + ) PCM Connector, Harness Side ( - ) 12 Volt Vehicle Battery APPS3 Negative terminal
Is the resistance greater than 10K ohms?
Yes No GO to DK20. REPAIR the short circuit to GND. CLEAR the DTCs. REPEAT the self-test. - Measure the resistance between:
- DK20 CHECK THE APPS3 CIRCUIT FOR A SHORT IN THE HARNESS
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) APP Sensor Connector, Harness Side APPS3 ETCRTN APPS3 ETCREF
Are the resistances greater than 10K ohms?
Yes No GO to DK21. REPAIR the short circuit. CLEAR the DTCs.
REPEAT the self-test. - Measure the resistance between:
- DK21 CHECK THE APPS3 CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
- Key ON, engine OFF.
- Measure the voltage between:
( + ) PCM Connector, Harness Side ( - ) 12 Volt Vehicle Battery APPS3 Negative terminal
Is any voltage present?
Yes No REPAIR the short circuit. CLEAR the DTCs.
REPEAT the self-test.GO to DK24. - DK22 CHECK THE APPS1 CIRCUIT FOR A SHORT TOGETHER
- Key in OFF position.
- PCM connector disconnected.
- APP Sensor connector disconnected.
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) APP Sensor Connector, Harness Side APPS1 APPS2 APPS1 APPS3 APPS1 ETCREF APPS1 ETCRTN
Are the resistances greater than 10K ohms?
Yes No GO to DK25. REPAIR the short circuit. CLEAR the DTCs.
REPEAT the self-test. - DK23 CHECK FOR THE APPS2 CIRCUIT SHORTED TO SIGNALS IN THE SAME HARNESS
- Key in OFF position.
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) APP Sensor Connector, Harness Side APPS2 APPS1 APPS2 APPS3 APPS2 ETCREF APPS2 ETCRTN
Are the resistances greater than 10K ohms?
Yes No GO to DK25. REPAIR the short circuit. CLEAR the DTCs.
REPEAT the self-test. - DK24 CHECK FOR THE APPS3 CIRCUIT SHORTED TO SIGNALS IN THE SAME HARNESS
- Key in OFF position.
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) APP Sensor Connector, Harness Side APPS3 APPS1 APPS3 APPS2 APPS3 ETCREF APPS3 ETCRTN
Are the resistances greater than 10K ohms?
Yes No GO to DK25. REPAIR the short circuit. CLEAR the DTCs.
REPEAT the self-test. - DK25 CHECK THE APP SENSOR CIRCUITS FOR AN INTERMITTENT CONCERN
- Wiggle, shake, and bend small sections of the wiring harness while working from the sensor to the PCM.
- Measure the resistance between:
( + ) APP Sensor Connector, Harness Side ( - ) PCM Connector, Harness Side APPS1 APPS1 APPS2 APPS2 APPS3 APPS3
Are the resistances less than 5 ohms?
Yes No GO to DK26. ISOLATE the concern and REPAIR as necessary.
CLEAR the DTCs. REPEAT the self-test. - DK26 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Visually inspect for:
- pushed out pins
- corrosion
- Connect all the PCM connectors and make sure they seat correctly.
- Carry out the PCM self-test and verify the concern is still present.
Is the concern still present?
Yes No INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.