I have the 418 current code?
Thread Starter
Melting Slicks
Joined: Dec 2003
Posts: 2,334
Likes: 11
From: las vegas nv.
I have the 418 current code?
But NO check engine light--its the Air Pump Relay Control Circuit--anyone have any idea, As to why the light wouldn't come on thx.
Last edited by bobby777; Aug 6, 2014 at 04:35 PM.
Burning Brakes
Joined: Jul 2006
Posts: 763
Likes: 45
From: Long Grove IL
The light doesn't come on until the second consecutive ignition cycle that the test fails.
Originally Posted by gm
Circuit Description
A voltage is directly supplied to the relay coil of the secondary air injection (AIR) pump. The powertrain control module (PCM) controls the relay by grounding the control circuit via an internal switch that is called a driver. The primary function of the driver is to supply the ground for the controlled component. Each driver has a fault line which the PCM monitors. When the PCM commands a component ON, the voltage of the control circuit should be low, near 0 volts. When the PCM commands the control circuit to a component OFF, the voltage potential of the circuit should be high, near the battery voltage. If the PCM receives a different voltage, from the fault detection circuit , than expected, 2 events occur. The fault line status changes, and the DTC sets.
The relay controls the high current flow to the AIR fuel-injection pump. This allows the PCM driver to control only the relatively low current that is used by the relay.
Conditions for Running the DTC
• The engine speed is more than 400 RPM.
• The system voltage is between 6-18 volts.
Conditions for Setting the DTC
• The PCM detects that the commanded state of the driver and the actual state of the control circuit do not match.
• All the above conditions exist for a minimum of 5 seconds.
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.
A voltage is directly supplied to the relay coil of the secondary air injection (AIR) pump. The powertrain control module (PCM) controls the relay by grounding the control circuit via an internal switch that is called a driver. The primary function of the driver is to supply the ground for the controlled component. Each driver has a fault line which the PCM monitors. When the PCM commands a component ON, the voltage of the control circuit should be low, near 0 volts. When the PCM commands the control circuit to a component OFF, the voltage potential of the circuit should be high, near the battery voltage. If the PCM receives a different voltage, from the fault detection circuit , than expected, 2 events occur. The fault line status changes, and the DTC sets.
The relay controls the high current flow to the AIR fuel-injection pump. This allows the PCM driver to control only the relatively low current that is used by the relay.
Conditions for Running the DTC
• The engine speed is more than 400 RPM.
• The system voltage is between 6-18 volts.
Conditions for Setting the DTC
• The PCM detects that the commanded state of the driver and the actual state of the control circuit do not match.
• All the above conditions exist for a minimum of 5 seconds.
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.
