P0506

DTC P0506

CIRCUIT DESCRIPTION
The throttle actuator (TAC) motor is controlled by the TAC module using various inputs from the powertrain control module (PCM) which are communicated across serial data. The DC motor located on the throttle body drives the throttle plate. In order to decrease idle speed, the TAC module commands the throttle closed, reducing air flow into the engine. In order to increase idle speed, the TAC module commands the throttle plate open, allowing more air to pass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, DTC P0506 sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0506 Idle Speed Low

CONDITIONS FOR RUNNING THE DTC
- DTCs P0068, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0125, P0128, P0171, P0172, P0201-P0206, P0220, P0300, P0401, P0404, P0405, P0443, P0496, P0502, P0503, P1106, P1107, P1111, P1112, P1114, P1115, P1125, P1404, P1516, P2101, P2107, P2108, P2119, P2120, P2125, P2135, P2138, and U0107 are not set.
- DTCs P0136, P0401, and P0420 have passed.
- The engine is operating.
- The engine coolant temperature (ECT) is more than -40°C (-40°F).
- The intake air temperature (IAT) is more than -40°C (-40°F).
- The barometric pressure (BARO) is more than 60 kPa.
- The system voltage is between 11-18 volts.
- The vehicle speed is less than 4.8 km/h (3 mph).
- The throttle position (TP) angle is less than 0.25 percent.

CONDITIONS FOR SETTING THE DTC
- The difference between the actual and desired idle RPM exceeds a calibrated limit. This limit varies from 300 RPM at -40°C (-40°F) to 100 RPM at 152°C (305°F) based on engine coolant temperature.
- The above conditions are present for 8 seconds in order for the test to fail. Four tests must fail in order to set this DTC. The vehicle must exit conditions for running between each test.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- 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 emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

Steps 1-5:

The number below refers to the step number in the diagnostic table.
2. This test determines whether the engine can achieve the commanded RPM. If the engine does not reach the commanded RPM, the test determines whether the RPM is too high or too low.