Powertrain, generic (extended)

P2B05 Cylinder 6 Injection Pulse Performance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P2B05 marks missed injection pulses on cylinder 6 outside the cold-start window; on a six-cylinder engine this is the last cylinder in the order of numbers. No manufacturer documents P2B05 publicly as a stand-alone check. GM's 2025 V8 calibration (25OBDG06A/06B) lists it only in the support tables shared by the pulse family. One of them shows why the check is tied to split injection: double or triple pulses are allowed only up to about 3,000–3,600 rpm, depending on mode and injector energy profile, and per GM's 2018 definitions single-pulse data are evaluated below 5,000 rpm. A fault therefore tends to show at low and medium speed. The injector of cylinder 6 is first suspect, wiring second; the cold-start counterpart is P2B0D.

Likely causes

Deposits or wear on the cylinder 6 injector hampering small pulses

Contact problem at the injector 6 plug

Injector driver or voltage sensing in the ECM faulty

Symptoms

Check engine light
Slight shaking at idle or low speed, misfire on cylinder 6 (P0306)

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€100–1,000

Time0.5–5 h

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

Parts involved

fuel injector cylinder 6injector wiringengine control module

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