P1579

Circuit Description

This diagnostic test is used to detect the vehicle transaxle being placed in gear under conditions that may cause damage to the vehicle powertrain or create an unsafe condition. When such a condition exists, DTC P1579 is set and engine power will be reduced by disabling fuel to individual cylinders.

Conditions for Running the DTC

DTCs P0122 and P0123 not set.

Conditions for Setting the DTC

^ Gear selection from Park or Neutral to Drive or Reverse.
^ Vehicle speed less than 6 MPH.
^ Engine speed greater than 2000 RPM.
^ Throttle angle of 20 degrees or greater.

Action Taken When the DTC Sets

PCM will retard spark and disable fuel to individual cylinders to reduce engine power.

^ The Malfunction Indicator Lamp (MIL) will not illuminate.
^ The PCM will command a message to be displayed.
^ The PCM may record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records.

Conditions for Clearing the Message/DTC

^ The PCM will turn the message OFF after one run and pass of the diagnostic test.
^ A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.
^ A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
^ Use a scan tool to clear DTCs.
^ Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended.

Diagnostic Aids

If the drivers actions caused this DTC to set, clear the DTC and inform customer of proper shift procedure.

Manipulate the wire harness while watching the scan tool display looking for opens and shorts.

Reviewing the Failure Rec. may help diagnose an intermittent failure by showing how long ago and under what conditions the DTC set.