Circuit Description
The throttle position (TP) sensor is a potentiometer. The powertrain control module (PCM) supplies the TP sensor a reference voltage, a signal, and ground circuits. When the throttle is depressed, the TP sensor signal rises to near the reference voltage. When the throttle is released, the TP sensor signal decreases from the reference voltage. The control module monitors the TP sensor signal circuit voltage in order to determine the throttle blade angle, or opening.
This diagnostic trouble code (DTC) is designed to detect a TP sensor signal voltage higher than the possible operating range of a normally functioning TP sensor.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The TP sensor signal voltage is more than 4.7 volts for 1 second or more.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
The scan tool reads the throttle position in volts. The scan tool should read between 0.45-0.85 volt with the throttle closed and the ignition switch turned ON or at idle. The voltage should increase at a steady rate as the throttle is moved toward the WOT position.
The scan tool will read the throttle angle percentage. 0 percent equals closed throttle. 100 percent equals wide open throttle (WOT).
Scan the TP sensor while depressing the accelerator pedal with the engine turned OFF and the ignition turned ON. The display should vary from less than 1.25 volts (1,250 mV) with the throttle closed to more than 4.5 volts (4,500 mV) when the throttle is held at the WOT position.
This DTC will result if the TP ground circuit is open or the TP sensor signal circuit is shorted to voltage. Refer to Symptoms - Engine Controls .
An intermittent may be caused by any of the following conditions:
| • | A poor connection |
| • | Rubbed through wire insulation |
| • | A broken wire inside the insulation |
Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Test Description
The number below refer to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 |
Does the scan tool indicate that the TP sensor voltage is greater than the specified value? | 4.9 V | Go to Step 4 | Go to Step 3 |
3 |
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to DTC P1122 |
4 |
Does the scan tool indicate that the TP voltage is at the specified value? | 0.0 V | Go to Step 5 | Go to Step 7 |
5 | With a DMM, test the TP sensor 5 volt reference circuit for voltage. Does the DMM indicate that the TP voltage parameter is at the specified value? | 5.0 V | Go To Step 6 | Go to Step 8 |
6 | Test the low reference circuit of the TP sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 10 |
7 | Test the signal circuit of the TP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 10 |
8 | Test all 5-volt reference circuits for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
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? | -- | Go to Step 13 | Go to Step 11 |
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? | -- | Go to Step 13 | Go to Step 12 | |
11 | Replace the TP sensor. Refer to Throttle Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
12 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
13 |
Does the DTC run and pass? | -- | Go to Step 14 | Go to Step 2 |
14 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
