Circuit Description
The Throttle Position (TP) sensor provides a voltage signal that changes relative to the throttle opening. The TP sensor signal voltage varies from about 0.35 volt at idle to about 4.65 volts at Wide Open Throttle (WOT). The TP sensor signal input is used by the ECU for fuel trim and diagnostic functions.
This is a type B DTC.
Conditions for Setting the DTC
| • | The vehicle is in the CNG operation mode. |
| • | The TP sensor circuit voltage is greater than 4.9 volts. |
Action Taken When the DTC Sets
The ECU sets the DTC 21 after two consecutive driving cycles with the fault active.
Conditions for Clearing the MIL/DTC
The ECU turns the MIL off after three consecutive driving trips without a fault condition present. A DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 72°F (40°C) from the start-up coolant temperature and the engine coolant temperature exceeds 160°F (70°C) during that same ignition cycle) or the code clearing procedure has been used.
Diagnostic Aids
Always diagnose ANY PCM codes that are present before beginning this diagnostic procedure.
A scan tool displays the throttle position in volts. It should display 0.20 volt to 0.90 volt with the throttle closed and the ignition ON or at idle. The voltage should increase at a steady rate as the throttle is moved toward Wide Open Throttle (WOT). Also, the scan tool displays the throttle angle percentage where 0% = closed and 100% = WOT.
Scan the TP sensor signal while depressing the accelerator pedal with the engine stopped and the ignition ON. The display should vary from below 1.25 volts when the throttle is closed to over 4.5 volts when the throttle is held in the Wide Open Throttle (WOT) position.
This DTC will result if the TP ground circuit is open or the TP signal circuit is shorted to the voltage.
If the DTC is intermittent, refer to Intermittent Conditions .
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
If the TP sensor signal measures greater than 4.9 volts, the fault exists.
-
With the ECU connector disconnected and the voltage still present, this eliminates the ECU as the possible cause of the fault.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the AF Powertrain OBD System Check performed? | -- | Go to Step 2 | Go to Alternative Fuels (AF) Powertrain On Board (OBD) System Check |
Does the scan tool display the TP sensor signal greater than the specified value? | 4.9 V | Go to Step 3 | Go to Step 6 | |
3 | Using a DVOM, backprobe the TP sensor signal in the ECU connector. Does the DVOM display the TP sensor signal greater than the specified value? | 4.9 V | Go to Step 4 | Go to Step 7 |
Does the DVOM display the TP sensor signal greater than the specified value? | 4.9 V | Go to DTC P0123 TP Sensor Circuit High Voltage in Engine Controls - 2.2L in the J Platform Service Manual | Go to Step 5 | |
5 | Replace the ECU. Refer to Engine Control Unit Replacement . Is the action complete? | -- | Go to Step 9 | -- |
6 | Inspect the TP sensor connector and connector C018 for damaged or bent pins and corrosion. Was a problem found? | -- | Go to Step 8 | Go to Step 7 |
7 | The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs are stored, refer to those tables first. Are any additional DTCs stored? | -- | Go to the applicable DTC table | Go to Diagnostic Aids |
8 | Repair as needed. Refer to Wiring Repairs in Engine Controls - 2.2L in the J Platform Service Manual. Is the action complete? | -- | Go to Step 9 | -- |
9 |
Did the diagnostic run and pass? | -- | Go to Step 10 | Go to Step 2 |
10 | Are any ECU or PCM DTCs displayed that have not been diagnosed? | -- | Go to the applicable DTC table | System OK |
