Circuit Description
The throttle position (TP) sensor circuit provides a voltage signal that changes relative to the throttle blade angle. The signal voltage varies 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 greater than the range of the TP sensor, DTC P1121 will be set.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
TP sensor intermittently indicates a throttle position signal greater than 4.9 volts.
Action Taken When the DTC Sets
The PCM stores the conditions which were present when the DTC set as Fail Records data only.
Conditions for Clearing the MIL/DTC
| • | A history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC may be cleared using the scan tool Clear Info function or by disconnecting the PCM battery feed. |
Diagnostic Aids
Inspect for the following conditions:
| • | A faulty connection at the PCM or the sensor. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. |
| • | Inspect the wiring harness for damage. If the harness appears to be OK, observe the throttle position display on a scan tool while moving the connectors and wiring harnesses related to the TP sensor. A change in the display indicates the location of the malfunction. |
If DTC P1121 cannot be duplicated, reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||||
2 | Use a scan tool in order to select DTC info, Last Tst Fail and note any other DTCs set. Is DTC P0123 also set? | -- | Go to DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage | |||||||||
3 | Is DTC P1106 or P1635 also set? | -- | ||||||||||
4 | Test for a faulty sensor ground circuit terminal connection at the throttle position (TP) sensor. Was a problem found? | -- | ||||||||||
5 | Test the TP signal circuit between the TP sensor connector and the PCM for an intermittent short to voltage. Was a problem found? | -- | ||||||||||
6 | Test for an intermittent short to voltage in the following circuit(s):
Was a problem found? | -- | ||||||||||
7 | Inspect for a faulty sensor ground terminal connection at the PCM. Refer to Connector Repairs in Wiring Systems. Was a problem found? | -- | ||||||||||
8 | Test for an intermittent open in the sensor ground circuit. Refer to Wiring Repairs in Wiring Systems. Was a problem found? | -- | Go to Diagnostic Aids | |||||||||
9 | Replace the malfunctioning harness connector terminal in the sensor ground circuit. Refer to Connector Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||||
10 | Repair an intermittent open/short circuit in the wiring harness as necessary. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||||
11 |
Does the scan tool indicate DTC P1121 failed? | -- | System OK |
