Circuit Description
The throttle position (TP) sensor is used by the PCM in order to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits, a 5-volt reference circuit, a low reference circuit, and a signal circuit. Rotation of the TP sensor from the closed throttle position to the wide open throttle (WOT) position provides the PCM with a signal voltage from less than 1 volt to more than 4 volts through the TP sensor signal circuit. If the PCM detects an intermittent, excessively-high signal voltage, this DTC will set.
Conditions for Running the DTC
The ignition switch is ON.
Conditions for Setting the DTC
| • | The TP sensor voltage is more than 4.8 volts. |
| • | The intermittent condition exists for a total of 1 second during a 20 second period. |
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Conditions for Clearing the DTC
| • | 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 non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Diagnostic Aids
Electromagnetic interference (EMI) can cause an intermittent DTC. Inspect the related circuits for being too close to the secondary ignition wires and to the generator.
If the engine has sat overnight, the engine coolant temperature and the intake air temperature values should display within a few degrees of each other. If the temperatures are not within 3°C (5°F), refer to Temperature Versus Resistance .
For an intermittent condition, refer to Intermittent Conditions .
Test Description
The numbers below refer to step numbers on the diagnostic table.
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If DTC P0123 also failed, a hard failure is present. When a hard failure is present, both the hard and the intermittent DTCs will set.
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When moving related connectors, inspect the connectors for the following:
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When moving related wiring harnesses, inspect the wiring for the following conditions:
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The Freeze Frame/Failure Records data help to locate an intermittent condition. If you cannot duplicate the DTC, the information in the Freeze Frame/Failure records can help to determine how many miles have occurred since the DTC set. The Fail Counter and the Pass Counter can also be used to determine how many ignition cycles have occurred since the diagnostic reported a pass and/or a fail. If this DTC runs and passes the diagnostic, the scan tool will not indicate any information under DTC Status. In order to isolate when the DTC failed, operate vehicle within the same Freeze Frame conditions that you noted. These conditions include the RPM, the vehicle load, the vehicle speed, and the temperature.
| • | Poor mating of the connector halves, or a terminal not fully seated in the connector body |
| • | Improperly formed or damaged terminals--Carefully reform or replace all connector terminals in the related circuits in order to ensure proper terminal contact tension. |
| • | Poor terminal to wire connection--Inspect for poor crimps, and for crimping over wire insulation rather than over the wire. |
| • | Dirt or corrosion on the terminals--Inspect for missing connector seals, and inspect for damage to the connector seals. |
| • | Wire insulation that is rubbed through, causing an intermittent short. |
| • | Wiring broken inside the insulation |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
Did DTC P0123 fail this ignition cycle? | Go to DTC P0123 | Go to Step 3 | |
Does sensor value change abruptly while a related connector is being moved? | Go to Step 6 | Go to Step 4 | |
Using a scan tool, observe affected sensor value while moving related wiring harnesses. Does sensor value change abruptly while moving related electrical harnesses? | Go to Step 7 | Go to Step 5 | |
Does the scan tool indicate that this diagnostic failed this ignition? | Go to Step 8 | Go to Diagnostic Aids | |
6 | Repair any damaged connectors or terminals. Refer to Connector Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
7 | Repair any faulty wiring. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
8 |
Did you complete the replacement? | Go to Step 9 | -- |
9 |
Does the DTC run and pass? | Go to Step 10 | Go to Step 2 |
10 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK | |
