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P0283: Cylinder 8 Injector Circuit High

Severe

Quick answer

P0283 means the engine computer sees voltage higher than expected in the cylinder 8 injector control circuit, most often an open circuit: a broken wire, a backed-out connector pin, or an injector winding that failed open. The cylinder usually goes completely dead. Check the connector first, then let a resistance reading settle whether the injector itself is the problem.

What it means

The ECM expects the cylinder 8 injector circuit to sit at supply voltage when resting and to pull down when it grounds the circuit to fire the injector. P0283 sets when the voltage stays high when it shouldn’t, usually because the circuit is open and no current can flow, or because the wire is touching a power feed somewhere (a short to voltage).

“High” is the opposite story from P0282: instead of current escaping to ground, the path is broken or being fed voltage from outside. An open circuit means the injector never fires at all, so cylinder 8 goes dead and lean: expect the misfire code P0308 alongside. One trap worth knowing: an injector that previously shorted can overheat and damage its ECM driver transistor, and the damaged driver then shows up as a high code even after the injector is replaced.

Compared with the generic P0208, this code hands you the test plan: hunt for the open, pin, wire, or winding, before suspecting anything exotic.

P0283 symptoms: what you'll notice

  • A dead miss on cylinder 8: a steady, rhythmic stumble at idle, like the engine is limping on the remaining cylinders.
  • Noticeable loss of power and hesitation under load: the engine is down a full cylinder.
  • A check engine light that may flash; the dead cylinder’s unburned mixture overheats the catalytic converter.
  • Worse fuel economy, and sometimes a fault that appears suddenly after other engine work: the classic sign of a connector left unclipped.

Common causes

Ordered from most to least likely.

  1. 1.

    Injector winding failed open

    An open solenoid reads infinite resistance on a multimeter: the fastest condemn-or-clear test in this family.

  2. 2.

    Broken wire or backed-out connector pin

    A pin pushed out of the connector body during previous work makes a perfect intermittent open.

  3. 3.

    Corrosion creating an open contact

    Heavy green crust can stop current entirely instead of leaking it: same connector, opposite code from a wet short.

  4. 4.

    Control wire shorted to battery voltage

    A chafe against a hot feed holds the circuit high; rarer than an open but produces the same code.

  5. 5.

    Damaged ECM injector driver

    Often collateral damage from a previously shorted injector: suspect it when a new injector and good wiring still set the code.

How to fix it: diagnosis, step by step

Cheapest and most likely checks first.

  1. 1 Scan and note companions

    Read all codes. P0283 with P0308 fits a dead cylinder from an open circuit; P0283 appearing right after other engine work points hard at a disturbed connector.

  2. 2 Inspect the connector pins closely

    Unplug the cylinder 8 injector connector and look straight into both halves: a backed-out, bent, or corroded pin is this code’s most common cause and a free fix. Tug each wire gently at the connector body: a broken crimp will give.

  3. 3 Measure resistance against a neighbor

    Measure across the injector pins and compare with the next cylinder. An infinite (open) reading condemns the cylinder 8 injector on the spot; a normal reading moves suspicion to the harness.

  4. 4 Check the harness for an open or short to power

    With both ends disconnected, check continuity end-to-end on the control wire (no continuity = broken wire), then check for voltage on it with the key on (voltage present = short to a power feed).

  5. 5 Swap-test before blaming the ECM

    Swap the injector with a neighbor and clear codes. Code follows the injector: replace it. Code stays on cylinder 8 with proven-good wiring: only then consider the ECM driver, and have the shorted-injector history in mind.

Parts & tools you may need

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Frequently asked questions

What does code P0283 mean?
P0283 means the engine computer sees voltage higher than expected in the cylinder 8 injector control circuit, most often an open circuit: a broken wire, a backed-out connector pin, or an injector winding that failed open. It’s serious: diagnose it promptly to avoid expensive damage.
What’s the difference between P0282 and P0283?
Opposite electrical directions on the same circuit. P0282 (low) means current is leaking to ground: shorts and shorted windings. P0283 (high) means the path is broken or fed outside voltage: opens, broken wires, backed-out pins. The hands-on tests are different, which is why the direction matters.
Why did P0283 come back after a new injector?
Because the injector was never the open (a broken wire or backed-out pin still interrupts the circuit) or because the original shorted injector damaged the ECM’s driver transistor before it died. Prove the harness with continuity tests before condemning the computer.
Can I drive with P0283?
Briefly and gently at most. The cylinder is almost certainly dead, which means raw mixture in the exhaust and a catalytic converter cooking itself. If the light flashes, stop driving.
Could it just be a loose connector?
Very plausibly, especially if the code appeared right after spark plug, intake, or injector work near cylinder 8. Unclip, inspect, clean, and firmly re-seat the connector before spending anything.
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