Powertrain, generic (extended)

P2547 Torque Management Request Input Signal A High

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modePossible

P2547 is logged when torque request A sits above the highest value the receiving module will accept. A wired input would read like a line touching a supply voltage or a lost ground at the sender; a bus message would carry an out-of-scale number. The receiver ignores such a request, since following it could mean an unwanted torque increase. No maker documents P2547 publicly. How input A is checked can be seen in GM's 2020 table 20OBDG04, where the engine module tests the transmission module's torque messages for protection value, rolling counter and an upper torque limit of 1,298 Nm, but under the general code P2544 rather than a separate high code. CARB requires such inputs to be monitored when they affect emissions or other diagnostics. P2546 is the low side, P2551 the high fault on input B.

Likely causes

Request line shorted to a supply voltage

Requesting module sends a value above the scale

Poor ground at the requesting module

Symptoms

Shift-related torque reduction no longer works, firmer shifts
Check engine light depending on make

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€60–700

Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

torque management input a

Related codes

P2544 P2545 P2546 P2551

References: law.cornell.edu, gsi.ext.gm.com.