Circuit Description
The throttle position (TP) sensor is used by the PCM to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with three circuits, 5 volt reference, low reference, and signal. The PCM provides the TP sensor with a 5 volt reference circuit and a low reference circuit. Rotation of the TP sensor rotor from the closed throttle position to the wide open throttle (WOT) position provides the PCM with a signal voltage from less than 1.0 volt to greater than 4.0 volts through the TP sensor signal circuit. If the PCM detects an excessively low signal voltage, this DTC will set.
Conditions for Running the DTC
Ignition is ON.
Conditions for Setting the DTC
| • | TP sensor signal voltage is less than 0.1 volts. |
| • | The above condition is present for longer than 1 second. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive 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/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has 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 a scan tool. |
Test Description
The numbers below refer to the step numbers 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 less than the specified value? | 0.1 V | Go to Step 4 | Go to Step 3 |
3 |
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to DTC P1121 |
4 |
Does the scan tool indicate TP sensor voltage is at the specified value? | 5V | Go to Step 11 | Go to Step 5 |
5 |
Does the DMM indicate voltage near the specified value? | 5V | Go to Step 9 | Go to Step 6 |
6 | With a DMM, test the TP sensor 5 volt reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 7 |
7 | Test all 5 volt reference circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 8 |
Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 | |
9 | With a DMM, test the TP sensor signal circuit for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 |
10 | Inspect for poor connections at the PCM harness connector. 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 14 | Go to Step 13 |
11 | Inspect for poor connections at the TP sensor harness connector. 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 14 | Go to Step 12 |
12 | Replace the TP sensor. Refer to Throttle Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
13 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
14 |
Does the DTC run and pass? | -- | Go to Step 15 | Go to Step 2 |
15 | With a scan tool, observe the stored information, Capture info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
