Diagnostic article Generic OBD-II
P2637: the transmission received an invalid engine-torque message
In the GM 5L40E T68 example, P2637 concerns validity of the engine-torque CAN signal, not a direct torque measurement.
Read before applying this article
Documented application
GM 2010 10OBDG08 transmission document, 5L40E T68 section. Only the cited monitor and calibration are described; per-code vehicle and engine applicability has not been established.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P2637 is an engine-torque message validity diagnosis in the cited transmission-control section. The transmission controller reports that the ECU's CAN torque signal is not valid. That is different from directly measuring an engine's physical torque and finding it too high or too low.
Validity and message content must be separated
A value displayed on a scan tool can be numerically plausible while the corresponding signal is marked invalid. Conversely, an unusual torque value does not by itself reproduce this code's validity test. Preserve the reporting module, the engine-torque signal status and any associated network or engine faults.
The table distinguishes this condition from an invalid torque-reduction request message. Those are separate messages within coordination between the engine and transmission. The exact code helps identify which part of that exchange the controller rejected.
Timing and supply conditions constrain the result
The source requires an invalid signal for at least two seconds and lists engine-speed and ignition-voltage enabling ranges. These conditions matter when an event occurs during starting, a low-voltage episode or another operating state outside the valid evaluation window.
The document does not identify a failed transmission solenoid, torque converter or engine-control module from P2637 alone. Follow the correct network and module diagnostic procedure to determine why the torque information was invalid. After correction, verify that the relevant message is both present and valid during an enabled monitoring period. Clearing stored faults or observing a torque number without its validity status is not equivalent evidence.
Source and applicability
GM 2010 10OBDG08 transmission document, 5L40E T68 section. Only the cited monitor and calibration are described; per-code vehicle and engine applicability has not been established.
10OBDG08 TRANS Diagnostics, physical PDF page 105.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Torque Management Feedback Signal A
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT