DTC P1519 Throttle Actuator Control (TAC) Module Internal Circuit. Cadillac Catera 2000

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2000 🢒 Catera 🢒 DTC 🢒 DTC P1519 Throttle Actuator Control (TAC) Module Internal Circuit

Handling ESD Sensitive Parts Notice
Engine Controls Components
Engine Controls (Throttle Position (TP) Sensor)
OBD II Symbol Description Notice

Circuit Description

When the ignition is turned to the ON position, the ECM operates the throttle valves in order to determine the integrity of the throttle control system prior to engine start-up. The ECM commands the throttle valves open momentarily and then commands the throttle valves to the closed position. Using information from the throttle position sensors, the ECM determines if the throttle valves are responding as commanded. The engine control module (ECM) controls the throttle valves by applying a varying voltage to the throttle valve motor.

Conditions for Running the DTC

•	The idle learn procedure is not active.

•	The duty cycle range switch is more than 80 percent.

Conditions for Setting the DTC

The ECM determines that an open or a short to ground is present in the throttle valve motor circuit, or an internal circuit fault was detected.

Action Taken When the DTC Sets

The ECM illuminates the malfunction indicator lamp (MIL) and records the operating conditions in the Freeze Frame on the first drive trip that the diagnostic runs and fails.

Conditions for Clearing the MIL/DTC

•	The ECM turns OFF the MIL after 3 consecutive drive trips that the diagnostic runs and passes.

•	A History DTC clears after 40 consecutive warm-up cycles in which there is no failure reported by this diagnostic or any other emission related diagnostic.

•	The scan tool clears the MIL/DTC.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

The throttle valves are spring loaded in a slightly open position and should move in either direction without binding. The throttle valves should always be under spring pressure.

When the ignition is turned ON, the ECM operates the throttle control motor to verify the integrity of the system prior to start-up. This can be seen by the momentary flash of the test lamp as the ignition is turned ON.

Step

Action

Values

Yes

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

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

With a scan tool, observe the DTC information to determine if any of the following DTCs are set.

•	Throttle position sensors

•	Accelerator pedal position sensors

•	Throttle actuator control system

Are any of these related DTCs set?

Go to the applicable DTC table

Go to Step 3

Turn OFF the ignition.
Visually inspect the throttle body for the following conditions. Refer to Diagnostic Aids:

•	Throttle valves that are NOT in the rest position

•	Throttle valves that are binding open or closed

•	Throttle valves that are free to move open or closed WITHOUT spring pressure.

Did you find any of these conditions with the throttle body?

Go to Step 14

Go to Step 4

Disconnect the TP sensor connector.
Turn ON the ignition with the engine OFF.

Important: The test lamp may momentarily flash when testing these circuits. This is considered normal.

Probe the throttle valve motor + and - circuit terminals with the test lamp connected to ground.

Did the test lamp illuminate and remain illuminated on either circuit?

Go to Step 7

Go to Step 5

Important: The test lamp may momentarily flash when testing these circuits. This is considered normal.

Probe the throttle valve motor + and - circuit terminals with the test lamp connected to battery positive.

Did the test lamp illuminate and remain illuminated on either circuit?

Go to Step 8

Go to Step 6

Turn OFF the ignition.
Connect the test lamp between the throttle valve motor + and - circuit terminals.
Observe the test lamp as you turn ON the ignition.

Does the test lamp flash ON and then turn OFF?

Go to Step 12

Go to Step 9

Turn OFF the ignition.
Disconnect the ECM connector C1.
Turn ON the ignition with the engine OFF.
Probe the throttle valve motor + and - circuit terminals with the test lamp connected to ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 13

Turn OFF the ignition.
Disconnect the ECM connector C1.
Probe the throttle valve motor + and - circuit terminals with the test lamp connected to battery positive.

Does the test lamp illuminate?

Go to Step 11

Go to Step 13

Turn OFF the ignition.
Disconnect the ECM connector C1.
Test the throttle valve motor + and - circuits for an open or high resistance.
Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 13

Repair the short to voltage on the circuit where the test lamp remained illuminated. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

Repair the short to ground on the circuit where the test lamp remained illuminated. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

Inspect for poor connections at the throttle body connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 14

Inspect for poor connections at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 15

Replace the throttle body assembly. Refer to Throttle Body/Throttle Position Sensor Replacement .

Did you complete the replacement?

Go to Step 16

Important: This vehicle is equipped with a theft deterrent system that interfaces with the ECM. Program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle.

Replace the ECM. Refer to Engine Control Module Replacement/Programming .

Is the action complete?

Go to Step 16

Turn OFF the ignition for 30 seconds.
Using the scan tool, clear the DTCs.
Start the engine.
Allow the engine to idle until the engine reaches the normal operating temperature.
Select DTC and the Specific DTC function.
Enter the DTC number that was set.
Operate the vehicle within the Conditions for Running this DTC until the scan tool indicates that the diagnostic Ran.

Does the scan tool indicate that the diagnostic Passed?

Go to Step 17

Go to Step 2

Does the scan tool display any additional undiagnosed DTCs?

Go to the applicable DTC Table

System OK