P2546: Torque Management Request Input Signal A Low

What it means

Torque management request input signal A is below the expected limit. The code does not identify the cause or fallback strategy.

At a glance

• Usually lights the check-engine light

How it works

Torque management request input signal A tells the powertrain control system to adjust engine torque. P2546 sets when that input is below its expected limit, which may mean the signal circuit is shorted to ground or a network request is stuck at its minimum; the code does not specify the resulting fallback behavior.

Common causes

Most likely first.

1. Signal wire shorted to ground
2. CAN message stuck at minimum value

Symptoms

• Check-engine or transmission warning light
• Reduced engine power or altered acceleration
• Transmission shifts may feel different

How to diagnose it

1. Review freeze-frame data and scan related modules for communication codes that could explain a minimum request value.
2. Check live data for torque management request input signal A and see whether it stays at its lower limit or changes with operating conditions.
3. Inspect the relevant signal and network wiring and connectors for damage, corrosion, or a wire shorted to ground.
4. Test the signal circuit and network communication using the wiring diagram and manufacturer's specification.
5. If the circuit passes, compare the request at the sending and receiving modules to identify whether a module is transmitting or reading the low value.

Common fixes

• Repair a signal wire shorted to ground.
• Repair damaged or corroded connectors affecting the request circuit.
• Correct a verified communication fault that holds the request at its minimum.
• Repair or replace a module only if testing confirms it is sending or interpreting signal A incorrectly.

Can I keep driving?

If engine power is reduced or acceleration and shifts are abnormal, drive gently and avoid overtaking, towing, or heavy acceleration. Stop somewhere safe if the vehicle cannot respond predictably to traffic.