P2B01 is stored when the ECM keeps missing the opening signature of the cylinder 2 injector in normal running, i.e. it has no proof that fuel was delivered on that cylinder's commanded pulses. GM uses the code on direct-injection petrol engines. The 2019 table for the 2.7 L L3B judges 100 failures out of 380 samples; the 2025 tables reach a verdict sooner, after 50 to 100 samples. Both are Type B with the warning lamp on the second trip. GM's preliminary information PIT5677 to PIT5677E for 2019–2021 Silverado and Sierra 1500 with the L3B lists P2B01 next to P2B00 and P2B03 among dozens of codes that a grounded, chafed engine harness can trigger. A misfire count on cylinder 2 (P0302) helps tell an injector problem from a wiring one; P2B09 is the cold-start version.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Cylinder 2 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- Warning lamp after two trips
- Uneven idle, possibly misfire on cylinder 2
- Together with many other codes and erratic behaviour when the harness is shorted
Most likely causes
- Engine harness shorted to ground at a chafe point (GM L3B bulletin series PIT5677)
- Cylinder 2 injector opening sluggishly or not at all (deposits, worn armature)
- Corroded or loose injector 2 connector distorting the feedback voltage
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P2B01 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- B: Subsystem depends on the code range
- 01: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2B01?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P2B01?
The most common causes are: engine harness shorted to ground at a chafe point (GM L3B bulletin series PIT5677); cylinder 2 injector opening sluggishly or not at all (deposits, worn armature); corroded or loose injector 2 connector distorting the feedback voltage.
Related codes
- P2B09Cold Start Cylinder 2 Injection Pulse Performance
- P2B00Cylinder 1 Injection Pulse Performance
- P2B02Cylinder 3 Injection Pulse Performance
- P2B96Injection Pulse Performance
- P02EFCylinder 2 Injector Circuit Range/Performance
- P0202Cylinder 2 Injector A Circuit/Open
- P0302Cylinder 2 Misfire Detected
Sources
- law.cornell.edu: 13 CCR 1968.2
- gsi.ext.gm.com: 19OBDG03D Diagnostics
- gsi.ext.gm.com: 25OBDG03A
- static.nhtsa.gov: MC 10193465 9999
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.