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DTC P1104

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P1104 00: Throttle Actuator Control (TAC) Motor Control Circuit Shorted

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Motor Control 1

P1516 00, P2101 00, P2176 00

P1516 00, P2101 00, P2176 00

P1516 00, P2101 00, P2176 00

P1516 00, P2101 00, P2176 00, P1104 00

Motor Control 2

P1516 00, P2101 00, P2176 00

P1516 00, P2101 00, P2176 00

P1516 00, P2101 00, P2176 00

P1516 00, P2101 00, P2176 00, P1104 00

Circuit/System Description

The engine control module (ECM) is the control centre for the throttle body throttle actuator control (TAC) system. The ECM determines the drivers intent and then calculates the appropriate throttle response. The ECM achieves throttle positioning by providing a pulse width modulated voltage to the throttle body (TAC) motor. The throttle body (TAC) motor system uses the following circuits:

    • Throttle body (TAC) motor control 1
    • Throttle body (TAC) motor control 2

Two processors are also used to monitor the throttle body (TAC) motor system data. Both processors are located within the ECM. Both processors monitor each others data to verify that the indicated throttle position is correct.

Conditions for Running the DTC

P1104 00

    • The ignition is ON or the engine is operating.
    • The ignition voltage is greater than 7 V.
    • The system is not in battery safe mode.
    • DTC P0068 00 is not set.
    • DTCs P1516 00 and P2101 00 run continuously once the above conditions are met for greater than 5 s.

Conditions for Setting the DTC

P1104 00

The indicated throttle position does not match the predicted throttle position for more than 0.5 s.

Action Taken When the DTC Sets

DTCs P1104 00 is a Type B DTC.

Conditions for Clearing the DTC

DTCs P1104 00 is a Type B DTC.

Diagnostic Aids

    • A high resistance condition with the throttle position sensor circuits may cause DTCs P1516 00, P2101 00, P2119 00, or P2176 00 to set.
    • 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

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, engine OFF, use a scan tool to observe the throttle position sensor 1 indicated position. Throttle position should increase as pedal is applied and decrease as pedal is released. When no accelerator pedal activity is detected, the throttle position will return to the spring loaded default position.
  2. Note: A low voltage condition may set this DTC.

  3. Review the freeze frame/failure records and ensure sufficient ignition voltage was present when the DTC was set.
  4. If voltage was low, verify with the owner that the battery was not discharged. If the battery has not been discharged, refer to Power Mode Mismatch .
  5. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Circuit/System Testing

Warning: Turn OFF the ignition before inserting fingers into the throttle bore. Unexpected movement of the throttle blade could cause personal injury.

  1. Inspect the Q38 Throttle Body for the following conditions:
  2. • 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 Q38 Throttle Body.

    Note: Disconnecting the throttle body harness connector causes additional DTCs to set.

  3. Ignition OFF, disconnect the harness connector of the Q38 Throttle Body.
  4. Verify that a test lamp does not illuminate between Q38 Throttle Body motor control 1 circuit terminal 3 or Q38 Throttle Body motor control 2 circuit terminal 5 and ground.
  5. If the test lamp illuminates, test the appropriate Q38 Throttle Body motor control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
  6. Ignition ON, test for 4.8-5.2 V between the Q38 Throttle Body motor control 1 circuit terminal 3 and ground.
  7. If less than the specified range, test the control circuit for short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
    If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
  8. Ignition ON, test for 4.8-5.2 V between the Q38 Throttle Body motor control 2 circuit terminal 5 and ground.
  9. If less than the specified range, test the control circuit for short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
    If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
  10. If all circuits test normal, replace the Q38 Throttle Body.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Throttle Body Assembly Replacement : 1.6L LDE, LXV, 1.8L 2H0, and LUW
    • Control Module References for engine control module replacement, setup, and programming
   


© Copyright Chevrolet. All rights reserved
   


© Copyright Chevrolet. All rights reserved