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 high signal voltage, this DTC will set.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
| • | TP sensor signal voltage is more than 4.9. |
| • | The above conditions are 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 greater than the specified value? | 4.8 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 that the TP voltage is at the specified value? | 0.0V | Go to Step 5 | Go to Step 8 |
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? | 5.0V | Go to Step 6 | Go to Step 9 |
6 | Connect a test lamp between the TP sensor low reference circuit and battery positive voltage. Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 7 |
7 | 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 18 | Go to Step 15 |
8 | 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 18 | Go to Step 15 |
9 | 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 18 | Go to Step 10 |
Did you observe a change in voltage while commanding the EGR? | -- | Go to Step 11 | Go to Step 14 | |
11 |
Did you observe a change in voltage while commanding the EGR? | -- | Go to Step 13 | Go to Step 12 |
12 | Replace the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- |
13 | Repair the short between the EGR Solenoid Control circuit and the 5 volt reference circuit. Refer to Wiring Repairs in Wiring Systems. | -- | Go to Step 18 | __ |
14 | 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 18 | Go to Step 16 |
15 | 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 18 | Go to Step 17 |
16 | Replace the TP sensor. Refer to Throttle Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
17 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- |
18 |
Does the DTC run and pass? | -- | Go to Step 19 | Go to Step 2 |
19 | With a scan tool, observe the stored information, Capture info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
