HomeTrouble CodesP2146

P2146 — Fuel Injector Group Supply Voltage Circuitopen

Manufacturer-specificPowertrain (engine & transmission)

OBD-II code P2146 indicates that the powertrain control module (PCM) has detected an open circuit in the voltage supply to a group of fuel injectors. This means the electrical path that provides power to the injectors is interrupted, preventing them from operating. The code is often set when the PCM commands the injectors but does not see the expected voltage feedback.

Symptoms

What causes it — most likely first

1. Open or shorted wiring in the injector supply circuit

Damaged, corroded, or broken wires between the fuse/relay and the injector connectors are the most common cause, interrupting voltage to the injector group.

2. Blown fuel injector fuse

A short to ground in the injector circuit or a failed injector can cause the fuse to blow, cutting power to the entire injector group.

3. Faulty fuel injector relay

A sticking or burned relay can fail to close the circuit, preventing voltage from reaching the injectors when the engine is running.

4. Failed fuel injector (internal short)

An injector with an internal short can draw excessive current, blowing the fuse or causing the PCM to disable the circuit to protect itself.

5. Corroded or loose connector at the injector or harness

Poor connections due to corrosion, moisture, or loose terminals can create high resistance or an open circuit, triggering the code.

6. PCM failure (rare)

A defective injector driver inside the PCM can cause an open circuit, but this is the least likely cause and should only be considered after all other possibilities are ruled out.

How it's diagnosed

  1. Check the fuel injector supply fuse and replace if blown; if the new fuse blows immediately, there is a short circuit in the wiring or an injector.
  2. Test the fuel injector relay by swapping it with a known good relay of the same type; if the code clears, replace the relay.
  3. Inspect the wiring harness and connectors for damage, corrosion, or loose pins, especially near the injectors and along the engine harness.
  4. Measure resistance across each injector in the affected group; compare to specifications. A shorted injector will have very low resistance.
  5. With the key on, engine off, check for battery voltage at the injector supply wire; if missing, trace the open circuit back to the fuse/relay.
  6. If all wiring, fuses, relays, and injectors test good, use a scan tool to command the injector circuit and check for PCM driver response; only then suspect a PCM fault.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Can I drive with a P2146 code?

It is not recommended. The engine may misfire, stall, or fail to start, which could leave you stranded or cause damage to the catalytic converter from unburned fuel.

Does this code mean I need to replace the PCM?

Almost never. The PCM is often misdiagnosed for this code, but the actual cause is usually a blown fuse, bad relay, or wiring issue. The PCM should only be considered after all other possibilities have been thoroughly ruled out.

Will a bad fuel injector cause a P2146 code?

Yes, a shorted fuel injector can draw excessive current and blow the supply fuse, which will set this code. Testing the injector resistance is an important diagnostic step.

Do I need to replace all the injectors if one is bad?

Not necessarily. Only the faulty injector needs replacement, but it is wise to inspect the others for similar wear or damage. The code refers to a circuit issue, not necessarily all injectors.