What Does P0283 Mean?
The ECM has detected an excessively high voltage or current in the cylinder 8 fuel injector circuit. This code is found on V8 and larger engines and indicates the electrical signal driving cylinder 8's injector exceeds the expected range. This could be from a shorted injector, wiring short to voltage, or ECM driver malfunction. The driver may notice rough running, excessive smoke, or engine knock from overfueling cylinder 8.
Common Causes
35%
Short to battery voltage in the cylinder 8 injector wiring harness
30%
Cylinder 8 fuel injector with internal short circuit (reduced coil resistance)
15%
Heat-damaged or corroded connector at the cylinder 8 injector
12%
ECM injector driver failure for the cylinder 8 output channel
8%
Wiring insulation degraded from exhaust heat exposure near cylinder 8
Diagnostic Steps
1
Measure cylinder 8 injector resistance at the connector — compare to factory specs. If resistance is significantly below the minimum specification, the injector is internally shorted.
2
Disconnect cylinder 8 injector and check harness pins for shorts — measure from each pin to battery positive and to ground. Any continuity indicates a wiring short that must be found and repaired.
3
Inspect the cylinder 8 injector connector and entire wiring run — on V8 engines, the rear cylinders' wiring is often exposed to high exhaust heat. Look for melted insulation, discolored connectors, or exposed copper.
4
Capture the cylinder 8 injector current waveform with a current clamp — compare the amplitude and shape to cylinder 7 or another known-good cylinder on the same bank.
5
Swap the cylinder 8 injector with cylinder 7, clear codes, and operate the engine — this determines whether the fault is in the injector or the wiring/ECM driver.
Estimated Repair Cost
$100 - $900
Parts + labor, varies by vehicle and location
The ECM has detected an excessively high voltage or current in the cylinder 8 fuel injector circuit. This code is found on V8 and larger engines and indicates the electrical signal driving cylinder 8's injector exceeds the expected range. This could be from a shorted injector, wiring short to voltag...
The most common cause of P0283 (Cylinder 8 Injector Circuit High) is: Short to battery voltage in the cylinder 8 injector wiring harness
Typical repair costs for P0283 range from $100 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
An injector circuit stuck high causes overfueling which can lead to engine knock, turbo damage from excessive exhaust heat, and catalytic converter overheating. Limit driving and avoid heavy loads until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0283 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection System
Difficulty
Type
Generic (SAE)
Recommended Tools
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