P1640
DTC P1640CIRCUIT DESCRIPTION
The engine control module (ECM) contains an output driver module (ODM) that controls four devices:
- The A/C relay
- The main relay
- The EVAP vent solenoid
- The EVAP purge solenoid
The ODM provides grounded output control of the above devices through separate control circuits. The ODM monitors the voltage level at each of the control circuits when the device is commanded ON or OFF. Each ODM output has an internal feedback circuit that connects to the ECM microprocessor. The ECM monitors voltage through the ignition 1 voltage circuit. Excessive voltage or current may cause damage to the ECM. If the ODM detects excessive current or voltage on an output control circuit, this DTC will set.
CONDITIONS FOR RUNNING THE DTC
The ignition is ON.
CONDITIONS FOR SETTING THE DTC
- The ODM has detected a voltage greater than 33 volts. OR Excessive current is detected on any circuit to the ODM.
- The above condition is present for 6 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.
DIAGNOSTIC AIDS
- A condition with the charging system may cause this DTC to set. Refer to Diagnostic System Check - Starting and Charging. Initial Inspection and Diagnostic Overview
- For an intermittent condition, refer to Intermittent Conditions. Intermittent Conditions
TEST
