Circuit Description
The throttle position (TP) sensor circuit provides a voltage signal that changes relative to the throttle blade angle. The signal voltage will vary from below 1.0 volt at closed throttle to above 4.0 volts at wide open throttle (WOT). The PCM monitors throttle position and compares actual throttle position from the TP sensor to a predicted TP value calculated from engine speed. If the Powertrain Control Module (PCM) detects an excessively low TP sensor signal voltage, DTC P0122 will be set.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | The TP sensor signal voltage is less than 0.1 volt. |
| • | The above conditions are present for more than 10 seconds. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the MIL during the first trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the malfunction indicator lamp (MIL) OFF during the third consecutive trip in which the diagnostic has been run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool. |
Diagnostic Aids
Inspect for the following conditions:
| • | Poor connection at the PCM and TP sensor--Inspect harness connectors for: |
| • | Backed out terminals |
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed or damaged terminals |
| • | Poor terminal to wire connection |
| • | Use a corresponding mating terminal to test for proper terminal tension. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, observe the TP Sensor display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems. |
If DTC P0122 cannot be duplicated, the information included in the Failure Records data can be useful in determining vehicle mileage since the DTC was last set. If it is determined that the DTC occurs intermittently, performing the DTC P1122 Throttle Position (TP) Sensor Circuit Intermittent Low Voltage diagnostic chart may isolate the cause of the malfunction.
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 |
Does the scan tool indicate that the TP voltage parameter is less than the specified value? | 0.16 V | ||
3 |
Does the scan tool indicate DTC P0122 failed? | -- | Go to Diagnostic Aids | |
4 |
Does the scan tool indicate that the TP voltage parameter is equal to the specified value? | 5 V | ||
5 |
Does the voltage measure equal to the specified value? | 5 V | ||
6 | Test the 5 volt reference circuit of the TP sensor for high resistance or an open and all 5 volt reference A circuits and connected components for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
7 | Test the signal circuit of the TP sensor for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
8 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
9 | Inspect for poor connections at the harness connector of the TP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
10 | Replace the TP sensor. Refer to Throttle Position Sensor Replacement . Did you complete the replacement? | -- | -- | |
|
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | -- | ||
12 |
Does the scan tool indicate DTC P0122 failed? | -- | System OK |
