EN

Severity: High Code type: Generic (all makes)

P2146 Code: Fuel Injector Group A Supply Voltage Circuit/Open

The shared power feed for one group of injectors is open, so every injector in that group has stopped.

At a glance

Severity: 4/5 – High4/5

Severity: High

Meaning
Fuel Injector Group A Supply Voltage Circuit/Open
System
Fuel & Air Metering · Powertrain
Safe to drive?
With caution
Typical repair cost
$50–$2,200
DIY difficulty
Hard

High-pressure injectors on common-rail diesels and gasoline direct-injection engines aren't fed straight from the 12-volt system. The ECU builds a boosted voltage internally, roughly 50-90 volts for solenoid injectors and well over 100 volts for piezo types, and sends it out through a few high-side stages, each shared by a group of injectors. It pairs injectors whose firing events never overlap, so one stage can serve them in turn. P2146 means the supply circuit of group A is open or carries no current. Because that wire is common, all injectors in the group go quiet together: on a four-cylinder usually two cylinders, on a V8 or inline six often three or four. Which injectors form group A differs by engine and ECU, so the wiring diagram is the first thing to open. A few port-injected gasoline engines use the same code for the fused 12-volt feed to a bank of injectors.

Can I keep driving? Losing a whole injector group can cut power by a third to a half with little warning, and many engines drop into limp mode. Drive only as far as needed to get off the road or to a shop, and don't merge onto a highway with the code active.

How to read P2146

How to read P2146P12213464
  1. P Powertrain
  2. 2 Generic (SAE)
  3. 1 Fuel & air metering
  4. 46 Specific fault

Symptoms

  • Sudden rough running with two or more cylinders dead at once
  • Heavy loss of power, often limp mode
  • Hard start or no start if the group is large
  • Misfire or cylinder contribution codes for exactly the cylinders in one group
  • Problem started right after injector, valve cover or head work

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Injector harness connector not latched or left unplugged after injector, valve cover or head work 26%
  2. Shared supply wire broken or chafed where it runs along the head or under the valve cover 24%
  3. Pins at the ECU or engine harness joint connector backed out or corroded 18%
  4. Open splice where the group A supply branches to its injectors 12%
  5. Failed high-side output stage or boost circuit inside the ECU 12%
  6. Blown fuse or failed relay on designs that feed the group with 12 volts 8%

Diagnosis step by step

Diagnostic flow: P21461Identify the group A injectors2Check recent work first3Measure the injectors of the group4Check the shared supply wire end toend5Inspect ECU pins and jointconnectors6Don't probe the live supply casually

  1. Identify the group A injectors

    Open the wiring diagram and note which ECU pin supplies group A and which injectors hang on it. Compare that with the cylinders the scan tool reports as misfiring or not contributing; if they match exactly, the fault is in the shared circuit, not in one injector.

    Tools: OBD-II scanner

  2. Check recent work first

    If injectors, glow plugs, a valve cover gasket or a head gasket were recently serviced, start at the connectors that were unplugged. A half-seated plug or a harness clip left loose is the quickest win.

    Tools: Flashlight

  3. Measure the injectors of the group

    Engine off, battery disconnected: measure each group A injector. Solenoid common-rail injectors read well under 1 ohm and gasoline DI injectors usually 1-3 ohms; piezo injectors read very high and need a dedicated tester. One open injector sets its own circuit code rather than P2146.

    Tools: Multimeter

  4. Check the shared supply wire end to end

    With the ECU unplugged, measure from the group A supply pin at the ECU connector to the supply pin at each injector in the group. Every path should read well under 1 ohm; an open to all of them points to the section before the branch, an open to one points after it.

    Tools: Multimeter

  5. Inspect ECU pins and joint connectors

    Look at the group A supply pin at the ECU and at any engine harness joint connector for pushed-back or burnt terminals and green corrosion. Test pin fit with the correct terminal probe rather than forcing a meter lead in.

    Tools: Flashlight, Multimeter

  6. Don't probe the live supply casually

    The group supply carries boosted voltage pulses that a multimeter can't read correctly and that can bite. If the wiring checks out, have the output verified with a lab scope and current probe before condemning the ECU, which then needs coding and injector data programmed.

    Tools: OBD-II scanner

Where the parts are

Ignition: coils and spark plugs per cylinder – P21461234567
Ignition: coils and spark plugs per cylinder
  1. 1Ignition coil
  2. 2Spark plug
  3. 3Fuel injector
  4. 4Camshaft sensor
  5. 5Crankshaft sensor
  6. 6Engine computer (ECM)
  7. 7Intake manifold

Repair options & costs

RepairDIY?Estimated cost
Reconnect and secure injector harness Yes $50–$150
Repair group A supply wire or splice No $150–$500
Replace internal injector harness (under valve cover) No $300–$900
Repair ECU connector terminals No $120–$350
Replace and program ECU No $900–$2,200

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Emissions / smog test impact

Will fail

P2146 keeps the check engine light on and usually sets misfire-related monitors as well, so the vehicle fails a state OBD-II inspection until the circuit is repaired and the monitors have run again.

Frequently asked questions

Why did two cylinders die at the same moment?

They share the group A supply. The ECU drives several injectors from one boosted output, so when that common feed opens, every injector on it stops together. That pattern alone tells you the fault isn't in a single injector.

Which cylinders are in group A on my engine?

It depends on the engine and ECU. Makers group injectors whose firing events don't overlap, which often means non-adjacent cylinders. The wiring diagram for your engine is the only reliable answer.

Is P2146 the same as P2149?

Same kind of fault, different group. P2146 concerns the group A supply, P2149 group B. If both are set together, look at what they share: the ECU's power and ground, or the ECU itself.

Can a bad injector cause P2146?

Rarely directly. An open injector normally sets its own circuit code, and a shorted one tends to set a low-voltage group code instead. P2146 points first to the shared wire, connectors and ECU output.

Sources