When several injectors appear to quit at once, the most useful clue may be what they share. Some diesel electronic systems organize injector supply or driver control into monitored groups. P2146–P2157 cover group supply voltage circuit open, low and high conditions across groups A through D. Their meaning is fundamentally different from a mechanical injector leakage code: they ask whether the electrical infrastructure supporting multiple injectors is behaving correctly.
The twelve-code group map
| Group | Circuit open | Circuit low | Circuit high |
|---|---|---|---|
| A | P2146 | P2147 | P2148 |
| B | P2149 | P2150 | P2151 |
| C | P2152 | P2153 | P2154 |
| D | P2155 | P2156 | P2157 |
The group letter does not universally identify a particular bank, pair or set of cylinders. Consult the engine’s electrical diagram and the exact fault-monitor description before choosing a connector to inspect. An eight-cylinder engine’s grouping may differ from the strategy on another engine, and a code that is not implemented on a particular platform should not be forced into its diagnosis.
Why a single fault can look like several bad injectors
A shared power path, supply driver, harness branch, terminal, or control module can affect more than one injector. The engine may run very poorly, stall or fail to start; several cylinder faults may be stored together. Replacing individual injectors without first resolving the shared circuit can leave every symptom unchanged. That is why a grouped electrical code deserves attention before a technician interprets a contribution test or fuel correction number.
How to narrow it down
A qualified technician identifies the exact group membership, checks electrical supply and grounds, reviews driver module communication and applies the manufacturer’s approved testing procedure. Injector electrical loading may also be relevant, but it must be measured using suitable equipment for the injector design. The decision to test a component follows the circuit evidence, not the order in which codes appeared on the scan tool.
See P0201–P0208, injector driver electronics and the injector electrical hub. Contact our diesel injection team if component-level evaluation becomes appropriate.
Frequently asked questions
Does P2146 prove all injectors in group A are defective?
No. It identifies a group supply circuit fault, and the common electrical path may be the problem.
Is group A always cylinders one and two?
No. Group composition is manufacturer- and system-specific.
Keep exploring the right evidence
Codes guide a diagnosis but do not identify a failed pump or injector by themselves. Review nearby systems, compare the exact engine application, and seek qualified testing before deciding on a repair.