P0212Generic code

P0212 Code: Cylinder 12 Injector Circuit Malfunction

The P0212 code means the engine computer detected an electrical fault in the cylinder 12 injector circuit. The cylinder 12 injector may not open, and that cylinder will misfire.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$20 to $500
Difficulty
Medium
System
Fuel Injection
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0212 code means

Each fuel injector gets 12 V all the time, and the computer opens it by connecting its other terminal to ground for a few milliseconds. While it does this, the computer watches the circuit voltage: when the injector closes, its coil produces a characteristic voltage spike. If the computer does not see the expected voltage or spike, it stores the P0212 code and turns on the check engine light.

Because the fault is tied to cylinder 12, the problem is usually in that one injector, its connector, or the wire that runs from it back to the computer. Cylinder numbering depends on the manufacturer. On most inline engines, cylinder 1 is the one closest to the timing belt or chain. On V engines, the odd and even cylinders are usually on different banks (bank 1 and bank 2). Confirm the numbering in the service manual before you take anything apart.

An injector that does not open leaves that cylinder with no fuel. The engine shakes, and the computer may also set a misfire code for that cylinder. Keep that in mind when you see the P0212 code next to a misfire code, because the misfire is often the result and the injector circuit is the cause.

P0212 code symptoms

  • Check engine light on.
  • Engine shaking, especially at idle.
  • Loss of power.
  • Misfire in the affected cylinder.
  • Smell of gas or high fuel consumption if the injector gets stuck open.

Likely causes of the P0212 code

  1. Injector 12 connector loose, broken or corroded. This is the most common cause, and the plastic clips tend to break from heat.
  2. Injector 12 coil open or shorted. Measure its resistance to find out.
  3. Control wire cut or rubbed through between the injector and the computer.
  4. No 12 V supply at that injector's connector.
  5. Injector driver for that cylinder inside the computer. This is uncommon, and the driver usually gets damaged when the injector was shorted.

How to diagnose the P0212 code step by step

  1. Read the codes with a scan tool, along with the misfire counters, to confirm which cylinder is misfiring.
  2. Inspect the connector on injector 12 for broken clips, bent pins and corrosion.
  3. Measure the injector resistance and compare it with the other injectors. They should all read about the same (as a rough guide, 11 to 18 ohms on a high-impedance injector).
  4. Check for 12 V at the connector with the key on.
  5. Plug in an injector test light (noid light) at the connector and crank the engine. It should flash. If it does not flash, the problem is in the control wire or in the computer.
  6. Swap the injector with the one from a neighboring cylinder. If the fault moves to the other cylinder, the injector is the culprit.

How to fix the P0212 code

  • Repair or replace the injector connector.
  • Replace the injector if its resistance is out of range.
  • Repair the control wire or the power supply.
  • If the driver inside the computer is damaged, replace the shorted injector that burned it out first, then deal with the computer.
  • Clear the codes and check in live data that there are no misfires.

Technical reference data

  • High-impedance gasoline injector: 11 to 18 ohms.
  • Low-impedance injector: 2 to 5 ohms.
  • Typical supply: 12 V from a relay or the computer, and the computer switches the ground side to open the injector.
  • Piezo common rail diesel injectors cannot be tested with an ohmmeter the same way. Follow the manufacturer's procedure for those.
  • These values are a rough guide, so check the manufacturer's data for your engine.

Brand-specific notes

On some brands the injector connector clip is a known weak point, and direct injection engines need a different test approach. The notes below only cover what is commonly reported for the P0212 code.

P0212 on Ford

The connector clip often breaks, and the injector loses contact with vibration. On EcoBoost direct injection engines, the injectors run at a higher voltage, so do not use a conventional test light without checking the procedure first.

P0212 on Nissan

It is common for the connector clip to break, and the injector then loses contact with vibration.

P0212 on Chrysler

It is common for the connector clip to break, and the injector then loses contact with vibration.

P0212 on Volkswagen

On TSI direct injection engines, the injectors work at a higher voltage. Do not use a conventional test light without checking the procedure.

P0212 on Hyundai

On GDI direct injection engines, the injectors work at a higher voltage. Do not use a conventional test light without checking the procedure.

Frequently asked questions about P0212

Can I drive with a P0212 code?
With caution and only for a short time. A cylinder with no fuel makes the engine shake, and if it is misfiring, the catalytic converter can get damaged.
Does the P0212 code always mean I need a new injector?
No. Many times it is the connector or the wire. Check the resistance and the signal before you buy a part.
How do I know which cylinder is affected?
Cylinder numbering depends on the manufacturer. On most inline engines, cylinder 1 is the one closest to the timing belt or chain. On V engines, the odd and even cylinders are usually on different banks. Confirm the numbering in the service manual before you take anything apart.
How much does it cost to fix P0212?
Roughly $20 to $500, depending on the repair. That ranges from a new connector to a new injector with labor, and it costs more on diesels.
What is the most common cause of P0212?
A loose, broken or corroded connector on the cylinder 12 injector. The plastic clips tend to break from heat, so check the connector before you replace the injector.
Will a P0212 code clear itself?
Not by itself in most cases. If the connector only loses contact now and then, the check engine light may go out and come back later, but the fault is still there until you repair it.

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