Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the electrical connection of the fuel injector for cylinder number 3. It's like a wire is touching something it shouldn't, causing trouble.
The code indicates an electrical fault where the high side of the H2 injector for cylinder 3 is shorted to the coil circuit.
P31B3 is triggered when the Engine Control Module (ECM) detects a short circuit between the high side of the hydrogen injector for cylinder 3 and the coil. This can lead to improper fuel injection and engine performance issues.
• Check Engine Light on
• Poor engine performance
• Rough idling
• Damaged wiring harness
• Faulty injector
• Short circuit in the coil
ECM: Engine Control Module
Injector: A device that introduces fuel into the engine's combustion chamber
• Inspect the wiring harness for damage or wear.
• Check the injector for proper operation.
• Test the coil for shorts or faults.
• Repair or replace damaged wiring.
• Replace the faulty injector.
• Fix or replace the coil if needed.
• Multimeter
• OBD-II scanner
• Wiring repair kit
$150 - $500
Moderate
• Toyota Mirai
• Hyundai Nexo
• Honda Clarity Fuel Cell
• Regularly inspect wiring for wear.
• Ensure proper maintenance of injectors.
• Avoid exposure of electrical components to moisture.
Electrical Issue
• Avoid driving the vehicle until repaired to prevent further damage.
• Consult with a professional mechanic for accurate diagnosis.
Check with your vehicle manufacturer for specific warranty coverage on fuel system components.
This code is relatively rare and specific to vehicles using hydrogen fuel cell technology.
High – Immediate attention is required to prevent potential engine damage.
Driving with this code may lead to increased emissions and potential safety risks due to engine malfunction.
• Engine running
• Vehicle stationary
The injector for cylinder 3 is located on the engine block, typically near the intake manifold.
Q: Can I drive with a P31B3 code?
A: It's not recommended to drive with this code as it can lead to engine damage and poor performance.
Q: How is a short circuit in the injector detected?
A: The ECM monitors the electrical signals and detects inconsistencies that indicate a short circuit.
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