Diagnostic Instructions
DTC Descriptors
DTC P2072: Throttle Actuator Control (TAC) System Ice Blockage
Circuit/System Description
The engine control module (ECM) controls the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control (TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors
the throttle position (TP) sensors 1 and 2 to determine the actual throttle valve position.
Conditions for Running the DTCs
• | The DTC runs continuously once the above condition is met. |
Conditions for Setting the DTC
DTC P2072
The ECM detects the throttle blade is stuck open or stuck closed for 1 second.
Action Taken When the DTC Sets
DTC P2072 is a Type A DTC.
Conditions for Clearing the DTC
DTC P2072 is a Type A DTC.
Diagnostic Aids
Inspect for a condition in which the throttle valve may have been held open. For example, ice may have formed in the throttle bore causing the throttle valve not to close.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Description and Operation
Throttle Actuator Control (TAC) System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Special Tools Required
J 34730-405
Injector Test Lamp
Circuit/System Verification
- Ignition ON, observe the scan tool DTC information parameter. Verify DTCs P0121, P0122, P0123, P0221, P0222, or P0223 are not set.
- Verify TP sensor 1 voltage is between 0.4-0.9 volt, and TP sensor 2 voltage is between 4.1-4.7 volts.
- Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times. DTC P2072 should not set.
⇒ | If any of the DTCs P0121, P0122, P0123, P0221, P0222, or P0223 set while performing this procedure, refer to
DTC P0121, P0122, P0123, P0221, P0222, or P0223
for further diagnosis. |
- Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. DTC P2072 should not set.
⇒ | If any of the DTCs P0121, P0122, P0123, P0221, P0222, or P0223 set while performing this procedure, refer to
DTC P0121, P0122, P0123, P0221, P0222, or P0223
for further diagnosis. |
- If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
Circuit/System Testing
- Inspect the throttle body for the following conditions:
• | A throttle blade that is not in the rest position |
• | A throttle valve that is binding open or closed |
• | A throttle valve that opens or closes without spring pressure |
⇒ | If a condition is found, replace the throttle body. |
Important: Disconnecting the throttle body harness connector causes additional DTCs to set.
- Ignition OFF, disconnect the harness connector at the throttle body.
- Install fused jumper wires between the throttle body and harness connector of the following circuits:
• | 5-volt reference circuit |
• | TP sensor 1 or TP sensor 2 signal circuit |
- Ignition ON, test for less than 0.5 volts on the motor control 1 and motor control 2 circuits.
⇒ | If greater than the specified value, test the appropriate motor control circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
Important: The scan tool TAC motor command is disabled, if multiple TP sensor or TAC circuit DTCs are set.
- Ignition OFF, command the TAC motor with the scan tool, while measuring the voltage of the TAC motor control 1 circuit and TAC motor control 2 circuit at the harness connector.
⇒ | If the voltage changes between 0.0 volts to greater than 10.5 volts on both circuits, replace the throttle body. |
⇒ | If the voltage changes between 0.0 volts to less than 10.5 volts on either
circuit, test for an open or a short to ground in the appropriate TAC motor control circuit. |
⇒ | If the circuits test normal, replace the ECM. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.