P0510

Closed Throttle Position (CTP) Switch Circuit:

Closed Throttle Position (CTP) Switch Circuit (continued):

Idle Control System:

Circuit Description

The Idle Speed Control (ISC) motor sends a Closed Throttle Position (CTP) switch signal to the Powertrain Control Module (PCM). The PCM applies 5 volts to the CTP switch. The CTP switch is closed with the engine idling (low voltage signal at the PCM) and open with the engine off idle (high voltage signal at the PCM). When the PCM detects a low voltage signal the throttle valve is closed, and when the PCM detects a high voltage signal the throttle valve is open.


Conditions for Setting the DTC

^ Off to on time: vehicle speed change from 0 to 32 km/h (0 to 20 mph) for 16 times.

^ On to off time: vehicle speed change from 0 to 32 km/h (0 to 20 mph) for 16 times.


Action Taken When the DTC Sets

^ The Malfunction Indicator Lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the fault active.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame buffer.


Conditions for Clearing the MIL/DTC


^ The MIL will turn "OFF" after three consecutively passing cycles without a fault present.

^ A History DTC will clear after 40 consecutive warm-up cycles without a fault.

^ DTC(s) can be cleared by using a scan tool or by disconnecting the PCM battery feed.


Diagnostic Aids

Check The Following Conditions:

^ When DTC P0107, P0122 and P0510, (P0450 if equipped) are set, it is possible that the reference circuit (LT. GRN wire) may be open
^ Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

^ Damaged harness. Inspect the wiring harness for damage.

^ If a parameter is available on the scan tool, use the CTP switch parameter instead of backprobing the PCM.

If DTC P051O 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.

If any wiring repairs need to be made, Refer to Repair Procedures in Diagrams.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. 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.

2. This test will determine whether the fault is present now. The scan tool should read "ON" when the throttle is closed and should read "OFF" when it is opened.

3. Review Freeze Frame data to determine when the DTC set. Always record this information.