DTC P2544
Diagnostic Instructions
DTC Descriptors
| DTC P2544: Transmission Torque Request Signal
Message Counter Incorrect |
Circuit/System Description
To improve shift feel, the transmission control module (TCM) may
request that the engine control module (ECM) reduce engine torque
during shift events. When such a request is received, the ECM
responds by retarding the base ignition timing and notifying the
TCM that the request has succeeded. If the ECM is unable to comply
with the request, the ECM sends the TCM a message that the request
has failed. The torque reduction request is sent to the ECM through
a communication network called the controller area network (CAN).
Two circuits are used to communicate CAN data between the ECM and
TCM. A fault in the CAN will not cause DTC P2544 to set by itself.
If a CAN fault occurs, other DTCs will set before DTC P2544. When
the TCM receives a torque reduction malfunction message from the
ECM, then DTC P2544 will set.
Conditions for Running the DTC
P2544
| • |
The ignition voltage is
10.2-15.5 V. |
| • |
The engine speed is running
for 0.5 s. |
| • |
Communication is
normal. |
| • |
No other CAN errors are
present. |
Conditions for Setting the DTC
P2544
The ECM notifies the TCM that a torque reduction request has failed
for 2 s.
Action Taken When the DTC Sets
P2544
| • |
DTCs P2544 is Type B
DTC. |
| • |
Driver requested engine torque
= maximum torque. |
| • |
The TCM commands maximum line
pressure. |
| • |
The TCM freezes transmission
adaptive functions. |
Conditions for Clearing the DTC
P2544
| • |
DTC P2544 is Type B
DTC. |
| • |
TCM receives engine actual
steady state torque validity is "Valid" for 5 min
continuously. |
Diagnostic Aids
This diagnostic trouble code may set due to low system voltage.
Ensure that the vehicle battery has passed a load test and is
completely charged, refer to
Battery Inspection/Test . Verify charging system is operating
correctly, refer to
Charging System Test . Verify there is no parasitic drain on
the battery, refer to
Battery Electrical Drain/Parasitic Load Test .
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
Description and Operation
Transmission Component and System Description
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| 1. |
Verify DTC U0100 and CAN DTCs
are not set. |
| ⇒ |
If DTC U0100 or CAN DTCs are set, diagnose these
first. |
| 2. |
Operate the vehicle within the
conditions for running the DTC. CAN DTCs should not set.
|
Circuit/System Testing
| 1. |
Ignition ON, attempt to
establish communication with the ECM with a scan tool. |
| 2. |
Test or replace the K20 Engine
Control Module. |
| ⇒ |
Verify DTC P2544 is not set. If DTC P2544 resets,
replace K71 Transmission Control Module. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
