DTC P1579 P/N to D/R at High Throttle Angle - Power Reduction Mode Active. Cadillac Seville 2000

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2000 🢒 Seville 🢒 DTC 🢒 DTC P1579 P/N to D/R at High Throttle Angle - Power Reduction Mode Active

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 more than 2000 RPM

•	Throttle angle of 20 degrees or more

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. Refer to Clearing Diagnostic Trouble Codes in Powertrain Control Module (PCM) .

Diagnostic Aids

If the condition is intermittent, refer to Intermittent Conditions in Symptoms.

Step	Action	Values	Yes	No
1	Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Since this DTC will set when the vehicle is shifted into DRIVE / REVERSE under possibly damaging conditions, check with the customer to verify the conditions under which the DTC set. Did the drivers actions cause this DTC to set?	--	Go to Diagnostic Aids	Go to Step 3
3	Check for proper adjustment of the transaxle range switch and for poor terminal contact at the switch and the PCM. If the condition is found, repair as necessary. Did you find and correct the condition?	--	Go to Powertrain Control Module Diagnosis	Go to Diagnostic Aids

Step

Action

Values

Yes

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Since this DTC will set when the vehicle is shifted into DRIVE / REVERSE under possibly damaging conditions, check with the customer to verify the conditions under which the DTC set.

Did the drivers actions cause this DTC to set?

Go to Diagnostic Aids

Go to Step 3

Check for proper adjustment of the transaxle range switch and for poor terminal contact at the switch and the PCM.
If the condition is found, repair as necessary.

Did you find and correct the condition?

Go to Powertrain Control Module Diagnosis

Go to Diagnostic Aids