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.

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

DTC P1504 is a Type B DTC.

DTC P1504 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. Start the engine, observe the scan tool DTC information parameter. DTC P1504 should not set.
2. 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.

1. Ignition ON, attempt to establish communication with the TCM with a scan tool.

⇒	If no communication with the TCM, refer to Scan Tool Does Not Communicate with CAN Device 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 and the CAN serial data high circuits.

⇒	If not within the specified range, test the CAN communication circuits between the ECM and the TCM for a short to voltage, short to ground or an open. If the circuit tests OK, replace the ECM.

4. If all circuits test normal, replace the TCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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