Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test DH: Throttle Position Sensor: Testing
| Fault Code | KOEO | KOER | Continuous Memory |
|---|---|---|---|
| P0068 | DH15 | DH15 | |
| P0121 | DH22 | DH22 | |
| P0122 | DH11 | DH11 | DH11 |
| P0123 | DH8 | DH8 | DH8 |
| P1120 | DH3 | DH3 | DH3 |
| P1121 | DH15 | DH15 | DH15 |
| P1124 | DH1 | DH1 | |
| P1125 | DH20 |
- 1) For KOEO & KOER Only DTC P1124: Check For Other DTCs
DTC P1124 is set when TP sensor rotation angle or voltage reading is less than 13.27 percent (.66 volt), or is more than 23.52 percent (1.17 volt) during KOEO or KOER self-test. Possible causes for this fault are:- Binding Or Bent Throttle Linkage
- TP Sensor Not Seated Properly
- Throttle Plate Below Closed Throttle Position
- Throttle Plate Screw Misadjusted
- Faulty TP Sensor
- Faulty Powertrain Control Module (PCM)
Perform KOEO ON-DEMAND SELF-TEST and KOER ON-DEMAND SELF-TEST . Check for DTC P0405 or P1400. If DTC P0405 or P1400 is present along with P1124, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If DTC P0405 or P1400 are not present with DTC P1124, go to next step.
- 2) Check For Binding Throttle Plate Or Linkage
Inspect throttle linkage and plate for binding. Ensure throttle plate is at closed position. If throttle linkage and/or plate is binding, or if throttle plate is not at closed position, repair as necessary. If throttle moves freely, opens fully and returns to closed throttle position and no mechanical concern is found, go to step 8). - 3) For KOEO, KOER & Continuous Memory DTC P1120: Check For Frayed Wires Or Corrosion On Connector Terminals
DTC P1120 is set when TP sensor rotation angle or voltage reading remains within calibrated range but falls between 3.42-9.85 percent (.17-.49 volt) during KOEO or KOER self-test. Possible causes for this fault are:- Frayed Or Corroded Circuit Wires Or Connectors
- VREF Circuit Open To TP
- VREF Circuit Shorted To SIG RTN Circuit
- Loose Connector Or Terminals At TP Sensor
Inspect TP sensor connector for loose, damaged or corroded terminals. Inspect wiring harness between TP sensor and PCM for damage or corrosion. Repair as necessary. If no concern is found, go to next step.
- 4) Check For Stuck 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 V PID, slowly move throttle plate from closed to wide open throttle position. If TP reading or (TP V) PID value indicates any sudden drop to less than 9.85 percent (.49 volt), go to next step. If TP and TP V PID readings increase and decrease gradually and smoothly, go to step 20). - 5) Check Voltage Between VREF & SIG RTN Circuits To TP Sensor
Turn ignition switch to OFF position. Disconnect TP sensor connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between VREF and SIG RTN terminals at TP sensor harness connector. See Figure, Figure and Figure . If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, reconnect TP sensor and go to TEST C, step 1). - 6) Check TP Circuit For Open In Harness
Turn ignition switch to OFF position. 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 Figure, Figure and Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in TP circuit. - 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:- TP Sensor Not Seated Fully
- TP Circuit Shorted To VPWR
- VREF Circuit Shorted To VPWR
- SIG RTN Circuit Open To TP Sensor
- Faulty TP Sensor
- 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 Figure, Figure and Figure . 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.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.