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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1996 🢒 DeVille 🢒 Engine 🢒 Engine Controls - 4.0L and 4.6L 🢒 DTC P1526 Minimum Throttle Position Not Learned

Object Number: 12985 Size: SF
Engine Controls Components
IAT/ ECT/ TP/ MAP and BBV Sensors
OBD II Symbol Description Notice
ESD Notice
ESD Notice

Circuit Description

The PCM learns the closed throttle position when the ignition is turned to LOCK. The closed throttle position is always corrected to 0 degrees. The correction is performed to allow for deposit buildup on the throttle valve. When the ignition is turned to LOCK, the PCM executes the TP sensor learning routine. If the same correction factor occurs on two consecutive key LOCK cycles, the TP sensor is then corrected to 0 degrees using the correction factor learned. This diagnostic test checks to see if initial TP sensor Learn values have been stored in the PCM. If these values have not been stored, DTC P1526 is set.

Conditions for Setting the DTC

Test Condition

Test continuously.

Failure Condition

No TP sensor learn value is stored.

Action Taken When the DTC Sets

    •  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 PCM Description and Operation.

Diagnostic Aids

Make sure nothing is touching or obstructing the accelerator or brake pedals during the TP learn procedure because this will prevent the PCM from performing the learn routine.

If DTC P1526 does not pass following the completion of the TP Sensor Learn Procedure, this may be due to incorrect or erratic signals from the TP Sensor.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

  1. The accelerator must not be moved or the procedure must be redone.

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to A Powertrain On Board Diagnostic (OBD) System Check

2

Are DTCs P0120, P0121, P0122, P0123, P1121, P1122 or P1524 also set?

--

Go to DTCs that are set

Go to Step 3

3

  1. Turn the key to LOCK.
  2. Ensure the throttle lever is not obstructed from being full closed.
  3. Turn the key ON.
  4. Wait 30 seconds.
  5. Turn the key to LOCK.
  6. After 30 seconds repeat the above steps.

Is the procedure complete?

--

Go to Step 4

--

4
  1. Wait 30 seconds with the key in LOCK.
  2. Turn the key ON.
  3. Using a scan tool In DTC select DTC INFO.

Does the display indicate Test Ran, Test Passed this ignition cycle?

--

System OK

Go to Diagnostic Aids