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 P1601: Lost Communication with TCM.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. |
| • | The engine is running greater than 2 seconds. |
| • | The ignition 1 voltage is greater than 11 volts. |
| • | No output controls are active. |
Conditions for Setting the DTC
The ECM does not detect a valid message from the TCM.
Action Taken When the DTC Sets
DTC P1601 is a Type B DTC
Conditions for Clearing the DTC
DTC P1601 is a Type B DTC
Reference Information
Schematic Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Engine running, observe the DTC information with a scan tool. DTC P1601 should not set.
Circuit/System Testing
- Ignition ON, attempt to establish communication with the TCM with a scan tool.
- Ignition OFF, disconnect the harness connector at the TCM.
- Ignition ON, test for 1.5-3.4 volts between the CAN serial data low circuit terminal K15 and the CAN serial data high circuit terminal K14.
- If all circuits test normal, replace the ECM.
| ⇒ | If no communication with the TCM, refer to Scan Tool Does Not Communicate with CAN Device for further diagnosis. |
| ⇒ | 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 the circuit tests normal, 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.
