Refer to
.
Circuit Description
The closed throttle position (CTP) switch sends a signal to the powertrain control module (PCM) indicating when the throttle is at idle (closed). The PCM applies 5 volts to the CTP switch. The CTP switch is closed when the engine is idling (low voltage signal at the PCM) and open when the engine is off idle (high voltage signal at the PCM). The CTP switch is located in the idle speed control motor.
Conditions for Setting the DTC
| • | Vehicle speed changes from 0.0 km/h to at least 32 km/h (0 to 20 mph). |
| • | The CTP switch did not indicate OFF (NOT IDLE) to ON (IDLE) or ON (IDLE) to OFF (NOT IDLE) during the change in vehicle speed. |
| • | The above conditions are present 16 times per ignition cycle. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) after two consecutive ignition cycles in which the diagnostic runs with the fault active. |
| • | The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer. |
Conditions for Clearing the MIL/DTC
| • | The MIL turns OFF after three consecutively passing trips without a fault present. |
| • | A History DTC clears after 40 consecutive warm-up cycles without a fault. |
| • | Use the scan tool Clear DTC Information function or disconnect the PCM battery feed in order to clear the DTC. |
Diagnostic Aids
Check for an open in the 5 volt reference circuit (LT GRN wire) when a DTC P0107, P0122, P0450, and P0510, are set.
An incorrectly adjusted TP sensor could cause a DTC P0510 to set. Refer to Throttle Position Sensor Adjustment .
An intermittent malfunction may be caused by a fault in the CTP switch electrical circuit. Inspect the wiring harness and components for any of the following conditions:
| • | Backed out terminals. |
| • | Improper mating of terminals. |
| • | Broken electrical connector locks. |
| • | Improperly formed or damaged terminals. |
| • | Faulty terminal to wire connections. |
| • | Physical damage to the wiring harness. |
| • | A broken wire inside the insulation. |
| • | Corrosion of electrical connections, splices, or terminals. |
If a DTC P0510 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.
Test Description
The numbers below refer to the step numbers in the diagnostic table.
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The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
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This step determines if fault is present. The scan tool should read IDLE when the throttle is closed and should read NOT IDLE when the throttle is open.
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This step checks the credibility of the CTP switch signal circuit.
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The CTP switch is located inside of the ISC motor assembly. The ISC motor must be replaced in order to service the CTP switch.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | |||
Did the CTP switch fail either test? | -- | |||
3 |
Does the scan tool indicate a DTC P0510? | -- | Go to Diagnostic Aids | |
4 |
Is the voltage near the specified value? | 5 volts | ||
5 | Probe the ISC motor ground circuit (harness side) with a test lamp connected to B+. Did the test lamp illuminate? | -- | ||
6 |
Did the CTP switch fail either test? | -- | ||
7 | Repair the open or the short in the 5 volt reference circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
8 | Repair the faulty connection or the open in the ISC motor ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
Was a repair necessary? | -- | |||
Replace the ISC motor. Refer to ISC Motor Replacement . Is the action complete? | -- | -- | ||
11 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | -- | |
12 |
Are any DTCs displayed on the scan tool? | -- | Go to the Applicable DTC Table | System OK |
