P2B3B: B Camshaft Profile Actuator B Control Circuit High Bank 1

For the second exhaust-camshaft profile actuator on bank 1 (camshaft B, actuator B), P2B3B means its control circuit is shorted to a voltage source. GM's L3B strategy checks this with the driver switched off: a resistance of no more than 0.5 Ω between the line and controller power counts as a fault, and four out of five such readings at a supply above 11 V store a Type A code, MIL on at once. Bulletin 21-NA-149, which covers chafed engine harnesses on 2019–2021 Silverado and Sierra 1500 pickups including the L3B, lists P2B3B among the possible codes. The affected exhaust sleeve can no longer be shifted on command, so the valve lift on that side stays as it is. P2B35 is the same fault on the intake side.

Medium severity. Can I keep driving?Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.

Symptoms

Check engine light comes on during the drive
Exhaust lift stays in one profile, cylinder deactivation blocked

Most likely causes

Control wire chafed against a live wire in the engine harness
Internal short in exhaust actuator B
Engine module output stage faulty

What to check, in order

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

Check the oil level and condition before anything else
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Check the solenoid valve's connector
Compare commanded and actual angles in live data
Test the solenoid valve and its filter, if it has one
Check the engine timing if there is chain noise

Good to know

Repair difficulty: medium
It can trigger limp mode.
It affects emissions.

What each character of P2B3B means

P: Powertrain: engine and transmission
2: Generic code: same on every make
B: Subsystem depends on the code range
3B: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2B3B?

Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.

What causes code P2B3B?

The most common causes are: control wire chafed against a live wire in the engine harness; internal short in exhaust actuator B; engine module output stage faulty.

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.