P0418

Refer to Engine Controls Schematics Secondary Air Injection (AIR) Pump Motors w/NB6-California Emissions.

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

CIRCUIT DESCRIPTION
The PCM uses Output Driver Modules (ODMs) to control many functions of the engine, and the transaxle. The ODMs supply the ground path for the PCM controlled device when the PCM commands the device ON. Each ODM is able to control several outputs. Unlike the Quad Driver Modules (QDMs) used in earlier model years, the ODMs are able to diagnose each output circuit. The PCM monitors the ODMs for circuit conditions that are incorrect for the commanded state of the ODM. If the PCM detects an improper circuit condition in the ODM that controls the AIR pump relay for cylinder bank 1, DTC P0418 will set.

CONDITIONS FOR RUNNING THE DTC
^ The engine is running.
^ The system voltage is between 8-16 volts.

CONDITIONS FOR SETTING THE DTC
^ The PCM detects an improper voltage level on the output circuit that controls the AIR pump relay for cylinder bank 1.
^ The condition exists for at least 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.
^ The PCM stores the conditions present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS
To determine whether an improper voltage level exists on the output circuit, the PCM compares the voltage level to the commanded state. For example, a failure condition exists if the PCM detects a low voltage level when the device is commanded OFF, or a high voltage level when the device is commanded ON.

Check for the following conditions:
^ Poor connections at the PCM or the AIR pump relay for cylinder bank 1. Refer to Testing for Intermittent and Poor Connections in Diagrams.
^ Damaged harness - Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM and turn the ignition ON. Connect a voltmeter between the AIR pump relay bank 1 control circuit and chassis ground. Turn the ignition ON and observe the voltmeter while moving connectors and wiring harnesses related to the for AIR pump relay bank 1 control circuit. A change in voltage will indicate the location of the malfunction. If a problem is found, repair as necessary. Refer to Wiring Repairs in Diagrams.

Reviewing the Fail Records vehicle mileage since the diagnostic, test last failed may assist in diagnosing the condition. The information may help in determining how often the condition occurs that caused the DTC to set.

TEST DESCRIPTION
The number below refers to the step number in the diagnostic table.
8. If diagnosis indicates a condition which causes the AIR pump(s) to run continuously such as an AIR Pump Relay control circuit shorted to ground, be sure to test for proper operation of the AIR pump(s).