P0C2B: Electric/Auxiliary Transmission Fluid Pump Control Module Feedback Signal

P0C2B concerns the status signal the auxiliary pump control module sends back to the controlling module. GM uses it on the Two-Mode hybrid trucks and SUVs (Tahoe, Yukon, Escalade, Silverado, Sierra, 2ML70): the hybrid controller expects a complete fault status message from the pump controller every 1.5 s; if it is missing or incomplete for 9.75 s with the vehicle in Run or Crank, the code sets as Type B, MIL after two trips. GM preliminary information PIP4751G stresses that P0C2B, with or without P2797, rarely means a bad pump: check the wiring, replace the pump control module if its date code is 089-11 or older, and note that a key held in Crank during a no-start can set it. P0C2C to P0C2E are the specific variants.

Medium severity. Can I keep driving?It depends on the symptoms. If the car is running normally you can go to a repair shop; if it goes into limp mode, drive as little as possible.

Symptoms

MIL after two drive cycles
Bumps, lulls or surges around auto-stops

Most likely causes

Wiring or terminal tension fault between hybrid controller and pump control module
Early pump control module (GM date code 089-11 or older)
Key held in crank for a long time during a no-start

What to check, in order

Start with the simplest. You can tick off each step.

Check the battery and grounds
Clear the code and see if it returns
If it is a reference voltage code, disconnect sensors one at a time and see if the voltage recovers
Check whether a software update is available
Do not replace the control module without a full diagnosis

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P0C2B means

P: Powertrain: engine and transmission
0: Generic code: same on every make
C: Subsystem depends on the code range
2B: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0C2B?

It depends on the symptoms. If the car is running normally you can go to a repair shop; if it goes into limp mode, drive as little as possible.

What causes code P0C2B?

The most common causes are: wiring or terminal tension fault between hybrid controller and pump control module; early pump control module (GM date code 089-11 or older); key held in crank for a long time during a no-start.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.