GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Aveo 🢒 Engine 🢒 Engine Controls and Fuel - 1.2L 🢒 DTC P1504

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 P1504: TCM Communication Performance.

Circuit/System Description

The controller area network (CAN) serial data bus is used by the engine control module (ECM) and automatic transmission control module (TCM) to share information. An example of information shared is engine speed, engine coolant temperature, manifold absolute pressure (MAP), throttle position and vehicle speed.

Conditions for Running the DTC
    • The ignition is ON or the engine is running.
    • The ignition 1 voltage is more than 10 volts.
    • The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM receives no valid vehicle speed data from the TCM for more than 1 second.

Action Taken When the DTC Sets

DTC P1504 is a Type A DTC.

Conditions for Clearing the DTC

DTC P1504 is a Type A DTC.

Reference Information

Schematic Reference

Engine Controls Schematics

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. Engine running, observe the DTC information with a scan tool. DTC P1504 should not set.
  2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing
  1. Ignition ON, attempt to establish communication with the TCM with a scan tool.
    2. ⇒If no communication with the TCM, refer to DTC U0100-U0299 for further diagnosis.
  2. Ignition OFF, disconnect the harness connector at the TCM.
  3. Ignition ON, test for 1.5-3.4 volts between the CAN serial data low circuit terminal 57 and the CAN serial data high circuit terminal 88.
    4. ⇒If not within the specified range, test the CAN communication circuits between the ECM and the TCM for an open, short to ground, or a short to voltage. If all circuits test normal, replace the ECM.
  4. If all circuits test normal, test or replace the TCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine and transmission control module replacement, setup, and programming