Circuit Description
The idle speed control (ISC) assembly is a throttle body with an integrated motor that is used to control the engine speed at idle. The engine control module (ECM) commands the integrated ISC motor to adjust the throttle angle for idle speed control. The ECM uses a high control circuit and a low control circuit to command the ISC motor. The ECM detects the adaptation value exceeds the throttle position (TP) sensor or the idle speed control (ISC) position sensor values, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1513 Idle Speed Control (ISC) System Performance
Conditions for Running the DTC
| • | The ignition is cycled from OFF to ON. |
| • | This DTC runs once per ignition cycle when the above condition is met. |
Conditions for Setting the DTC
The ECM detects the adaptation value exceeds the throttle position (TP) sensor or the idle speed control (ISC) position sensor values.
Action Taken When the DTC Sets - European Emissions
| • | The malfunction indicator lamp (MIL) will illuminate after 3 consecutive trips with a fail. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
Action Taken When the DTC Sets - Non European Emissions
The malfunction indicator lamp (MIL) will illuminate.
Conditions for Clearing the MIL/DTC - European Emissions
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Conditions for Clearing the MIL/DTC - Non European Emissions
| • | The MIL will turn OFF after the diagnostic runs without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Circuit Description
The idle speed control (ISC) assembly is a throttle body with an integrated motor that is used to control the engine speed at idle. The engine control module (ECM) commands the integrated ISC motor to adjust the throttle angle for idle speed control. The ECM uses a high control circuit and a low control circuit to command the ISC motor. If the ECM detects that the actual ISC motor position can not be commanded to the desired position, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1512 Idle Speed Control (ISC) System
Conditions for Running the DTC
| • | DTCs P0222 and P0223 are not set. |
| • | The engine is running. |
| • | The ignition 1 voltage is more than 10 volts. |
| • | The ISC motor angle is between 0.2° and 5.6°. |
| • | This DTC runs continuously once the above conditions are met. |
Conditions for Setting the DTC
The ECM detects that the actual ISC motor position can not be controlled to the desired ISC motor position for more than 5 seconds.
Action Taken When the DTC Sets - European Emissions
| • | The malfunction indicator lamp (MIL) will illuminate after 3 consecutive trips with a fail. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
Action Taken When the DTC Sets - Non European Emissions
The malfunction indicator lamp (MIL) will illuminate.
Conditions for Clearing the MIL/DTC - European Emissions
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Conditions for Clearing the MIL/DTC - Non European Emissions
| • | The MIL will turn OFF after the diagnostic runs without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connect End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |
2 |
Is DTC P0106, P0122, P0123, P0222, P0223, P0462, P0463, P0510, P1511, or P1512 also set? | -- | Go to Step 3 | |
3 |
Does the ISC motor position sensor parameter change when the throttle is open? | -- | Go to Step 4 | Go to Step 5 |
4 |
Does the DTC fail this ignition cycle? | -- | Go to Step 5 | Go to Intermittent Conditions |
Notice: Do NOT use the low reference circuit in the component harness connector for this test. Damage to the control module may occur due to excessive current draw. Important: Use a test lamp that measures more than 20 ohms for this test. Is the voltage more than the specified value? | 4.8 V | Go to Step 7 | Go to Step 6 | |
6 | Test the 5-volt reference circuit of the ISC motor position sensor for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 8 |
7 | Test for an intermittent and for a poor connection at the throttle body assembly. 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 11 | Go to Step 9 |
8 | Test for an intermittent and for a poor connection at the engine control module (ECM). 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 11 | Go to Step 10 |
9 | Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- |
10 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- |
11 |
Does the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 12 |
12 | Are there any DTCs that have not been diagnosed? | -- | System OK | |
