P026E

Fuel Injector Group B Supply Voltage Circuit Low

P026E is a generic OBD-II powertrain diagnostic trouble code: Fuel Injector Group B Supply Voltage Circuit Low. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P026E
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on, possible limp mode)
Need P026E disabled?
RaceTune permanently disables any OBD-II trouble code on supported ECUs — for motorsport, off-road, and export use.
→

What P026E means

P026E is set when the ECM detects that the supply voltage to fuel injector group B (typically the second bank of cylinders on multi-bank engines) is below the calibrated minimum threshold. Like its group A counterpart, this code signals a problem with the power delivery to the injector drive circuit rather than a fault with any single injector.

The injector supply voltage rail must remain within a tight tolerance for the injector driver transistors to open the solenoids with the correct current profile. A low-voltage condition on group B can result from an open feed wire, a degraded ground reference, a failing PCM high-side driver, or a shorted injector coil dragging the rail down. On V-configuration engines, each bank typically has its own supply circuit, making bank-specific faults like this one easier to isolate.

Diagnosis should start with reading all codes and checking live data to confirm which cylinders are affected. A wiring inspection covering the injector supply feed, the connector backshell, and individual injector coil resistance measurements will identify most root causes before any module-level diagnosis is needed.

Common causes

Most-frequently reported root causes when P026E is logged.

  • 1
    Open or high-resistance wire in the injector group B supply feed circuit.
  • 2
    Corroded or damaged connector pins at the injector harness plug on bank B.
  • 3
    Failed PCM or injector driver module output for the group B supply rail.
  • 4
    One or more shorted injector solenoids in group B pulling the supply voltage low.
  • 5
    Blown fuse or failed relay in the injector group B power distribution path.
  • 6
    Chafed wiring harness causing an intermittent short to ground.
  • 7
    Weak battery or charging system unable to maintain adequate rail voltage under load.

Symptoms drivers notice

MIL illuminated with P026E stored.
Misfires or rough running on the cylinders belonging to injector group B.
Hard start or extended cranking before the engine fires.
Noticeable power loss, especially under load.
Engine may enter limp or reduced-power mode.

How to diagnose P026E

A typical diagnostic flow when this code is present.

  1. 1
    Read all DTCs and note any companion misfire or injector circuit codes.
  2. 2
    Review live data for injector group B supply voltage and compare to battery voltage at idle.
  3. 3
    Inspect the group B injector wiring harness and connector for chafing, corrosion, or loose pins.
  4. 4
    Test the fuse and relay that power the injector group B circuit.
  5. 5
    Measure supply voltage at the group B injector connector with key on engine off.
  6. 6
    Measure individual injector coil resistance on bank B and compare to the manufacturer specification.
  7. 7
    If wiring and injectors test within specification, evaluate PCM driver health using factory-level diagnostics.

Related powertrain codes

Frequently asked questions

How is P026E different from P026B?

P026B affects injector group A (usually bank 1 or the first cylinder group), while P026E affects group B (bank 2 or the second group). Both indicate a low supply voltage fault on separate circuits.

Can a single bad injector cause P026E?

Yes. A shorted injector coil in the group can drag the entire supply rail below threshold and trigger the code.

Is it safe to continue driving?

No. The affected cylinders may not receive fuel, leading to misfires, exhaust damage, and potential engine harm.

Can low battery voltage trigger this code falsely?

Yes. A weak battery or failing alternator can reduce available rail voltage and set P026E without any injector or wiring fault. Always verify charging system health first.

Disabling P026E in software

RaceTune can permanently disable P026E — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

Got P026E in your scan?

Upload your ECU file — we'll identify the exact software version and confirm whether a disable is available for your car.

Upload your file