Circuit Description
The throttle position (TP) sensor circuit provides a voltage signal that changes relative to throttle blade angle. The signal voltage will vary from 1 volt at Closed Throttle to 4 volts at Wide Open Throttle (WOT). The TP signal is one of the most important inputs used by the powertrain control module (PCM) for fuel control and most of the PCM controlled outputs. If the PCM detects a TP signal voltage that is intermittently more than the range of the TP sensor, DTC P1121 will set.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
TP sensor intermittently indicates a throttle position signal more than 4.9 volts.
Action Taken When the DTC Sets
The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.
Conditions for Clearing the MIL/DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction free warm-up cycles. |
| • | The PCM receives a clear code command from the scan tool. |
Diagnostic Aids
Inspect for the following conditions:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
2 |
Important: If DTC P1635 5 Volt Reference Circuit is set, perform that diagnostic first. Is DTC P0123 set? | -- | Go to DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage | |
3 | Is DTC P1111, P1115, and/or P1106 also set? | -- | ||
4 | Test all 5 Volt Reference A circuits and connected components for an intermittent short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Diagnostic Aids | |
5 | Test the signal circuit of the TP sensor for an intermittent short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
6 | Test the ground circuit of the TP sensor for an intermittent open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
7 |
Did you find and correct the condition? | -- | ||
8 |
Did you find and correct the condition? | -- | Go to Diagnostic Aids | |
9 |
Does the DTC reset? | -- | System OK |
