P1641

DTC P1641 Malfunction Indicator Lamp (MIL) Control Circuit






Circuit Description

A dash light is illuminated by the PCM if diagnostics have detected certain errors related to the engine performance or engine sensor status. Illumination is accomplished by the PCM providing a ground path for the lamp circuit. This is a type D DTC.

Conditions for Setting the DTC

^ MIL requested "ON".
^ Voltage at the MIL control circuit is greater than 0 volts.
or
^ MW requested "OFF".
^ Voltage at the MIL control circuit is greater than 0 volts.

Action Taken When the DTC Sets

Will not turn "ON" the MIL.

Conditions for Clearing the MIL/DTC

^ A History DTC will clear when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle).
^ Use of a scan.

Diagnostic Aids

A faulty bulb or the control circuit shorted to ground will cause a P1641 to set.

Test Description

Number(s) below refer to the number(s) on the diagnostic table.

3. This test will check the control circuit for a short to ground.

5. This test will check the control circuit for an open.