P0202 – Injector Circuit/Open Cylinder 2

P0202 is an OBD-II trouble code that points to a problem with the fuel injector circuit on cylinder 2. When this code sets, your engine computer (ECU) has detected an electrical fault that can cause rough running, misfires, or even a no-start in severe cases. You might notice a check engine light, poor fuel economy, or a strong fuel smell. In this guide, you’ll learn what P0202 means, common causes, symptoms, and how you or your mechanic can diagnose and fix it without wasting time or money.

What Does P0202 Mean?

P0202 stands for “Injector Circuit/Open – Cylinder 2.” It means the ECU has detected an abnormal electrical condition (open, short, or out-of-range voltage) in the control circuit for the number 2 fuel injector. The injector itself may be faulty, or there may be a wiring or connector problem between the injector and the ECU.

The ECU constantly monitors injector circuit voltage and current. If it sees values outside the expected range for cylinder 2 for a set period of time, it stores P0202 and usually turns on the check engine light. This code is focused on the electrical side, not fuel pressure or mechanical engine issues, although those can show similar symptoms.

Quick Reference

• Code: P0202 – Injector Circuit/Open Cylinder 2
• Severity: Moderate to high (can cause misfire and drivability issues)
• Primary area: Fuel injector #2 and its wiring/connector
• Common fix: Repair wiring or replace injector #2
• Safe to drive?: Short term only if mild; avoid extended driving

Real-World Example / Field Notes

In the shop, I see P0202 most often on higher-mileage vehicles where heat and vibration have taken a toll on the injector harness. A typical case: a customer comes in with a rough idle, flashing check engine light, and a strong fuel smell. Scan tool shows P0202 and a misfire code for cylinder 2. A quick wiggle test on the injector connector makes the engine stumble even more. Pull the connector and you see green corrosion on the terminals and a cracked wire right at the plug. Clean terminals, repair the wire, clear the code, and the engine runs smooth again. The injector itself is fine; the wiring was the real culprit.

Symptoms of P0202

• Check engine light on: P0202 usually sets a solid or flashing MIL, often with misfire codes.
• Rough idle: Cylinder 2 may not be contributing properly, causing shaking at idle.
• Loss of power: Poor acceleration, especially under load, due to one cylinder not fueling correctly.
• Engine misfire: Noticeable stumble, hesitation, or jerking while driving.
• Poor fuel economy: Incomplete combustion or rich/lean conditions waste fuel.
• Fuel smell from exhaust: If the injector is stuck open, unburned fuel can reach the tailpipe.
• Hard starting or no-start: In severe cases, the engine may crank longer or not start at all.
• Black or sooty spark plug: Cylinder 2 plug may show signs of rich running or fouling.

Common Causes of P0202

Most Common Causes

• Faulty injector #2: Internal coil failure, stuck open/closed, or internal short/open in the injector.
• Damaged wiring to injector #2: Broken, chafed, or melted wires between the injector and ECU.
• Loose or corroded injector connector: Poor contact at the plug causing intermittent or high-resistance connection.
• Harness damage near engine: Heat and vibration near the valve cover or intake can crack insulation and break conductors.
• Previous repair errors: Incorrectly routed or pinched wires after head, intake, or valve cover work.

Less Common Causes

• ECU driver failure: The transistor inside the ECU that controls injector 2 can fail, though this is rare.
• Poor engine ground: High resistance in ground circuits can affect injector operation and circuit readings.
• Aftermarket modifications: Spliced-in remote starters, alarms, or performance injectors causing wiring issues.
• Rodent damage: Chewed injector harness, especially on vehicles parked outside for long periods.
• Connector water intrusion: Water or oil in the connector causing shorts or corrosion over time.

Diagnosis: Step-by-Step Guide

For P0202, you’ll want a basic scan tool (preferably with live data), a digital multimeter, and ideally a noid light or test light. A wiring diagram for your specific vehicle is very helpful. Safety first: work on a cool engine and disconnect the battery when probing connectors if you’re unsure.

1. Confirm the code: Use a scan tool to read codes and freeze frame data. Note engine RPM, load, and conditions when P0202 set. Check for related misfire or fuel trim codes.
2. Visual inspection: Locate injector #2 (consult firing order/diagram). Inspect the injector, connector, and harness for broken insulation, rubbing on metal, oil saturation, or obvious damage.
3. Wiggle test: With the engine idling, gently move the injector #2 harness and connector. If the engine stumbles or smooths out as you move it, you likely have an intermittent wiring or connector issue.
4. Check connector and terminals: Unplug injector #2 and look for bent pins, corrosion (green/white deposits), or loose terminals. Clean with electrical contact cleaner and ensure a snug fit when reconnecting.
5. Measure injector resistance: With the injector unplugged and key off, use a multimeter to measure resistance across the injector terminals. Compare to spec (typically 10–18 ohms for many port injectors, but verify for your engine). An open or very high/low reading indicates a bad injector.
6. Check power supply: With key on, back-probe the injector connector. One side should have battery voltage (often shared with other injectors). If there’s no power, trace back to the injector fuse or main harness.
7. Check ECU control (ground) side: Use a noid light or test light on the control wire while cranking or idling. The light should pulse as the ECU fires injector #2. No pulse with good power suggests a wiring break or ECU driver issue.
8. Continuity test: With battery disconnected, check continuity from injector #2 connector to the ECU connector pins. High resistance or open circuit means a break in the harness that must be located and repaired.
9. Swap test (if accessible): On some engines, you can swap injector #2 with another cylinder. If the code follows the injector (e.g., becomes P0203), the injector is faulty. If it stays on cylinder 2, the issue is wiring or ECU related.
10. Check Mode $06 and misfire data: On a more advanced scan tool, review Mode $06 and misfire counters for cylinder 2. This helps confirm that the issue is isolated to that cylinder and not a general fuel or ignition problem.

Pro tip: Don’t condemn the ECU until you’ve verified power, ground, and continuity on the injector circuit. ECU failures are much less common than a broken wire or corroded connector.

Possible Fixes & Repair Costs

The exact repair depends on what you find during diagnosis, but most P0202 fixes are straightforward once the root cause is identified.

• Replace injector #2: If resistance is out of spec or the injector fails a swap test, replace it. Parts typically run $75–$250 per injector, plus 0.5–2.0 hours labor depending on engine layout.
• Repair or replace wiring: Fix chafed, broken, or corroded wires with proper solder/heat-shrink or connector pigtails. Harness repairs usually cost $100–$350 depending on access and extent of damage.
• Replace injector connector: Many manufacturers sell pigtail kits. Expect $25–$60 for the connector plus 0.5–1.0 hour labor.
• ECU repair or replacement: If the injector driver is confirmed bad, ECU replacement or repair can run $400–$1,200 including programming.

In most cases, you’re looking at a total repair cost in the $150–$500 range for injector or wiring repairs at a typical shop. Costs vary with vehicle make, engine design (V6/V8 with buried injectors cost more), labor rates in your area, and whether additional parts (gaskets, fuel rail seals) are needed during disassembly.

Can I Still Drive With P0202?

You can often drive short distances with P0202, but it’s not ideal. If the engine just runs a bit rough and the light is steady, you can limp it to a shop or home. However, if the check engine light is flashing, the engine is shaking badly, or you smell raw fuel, you should avoid driving. A misfiring cylinder can overheat and damage the catalytic converter, wash down cylinder walls with fuel, and leave you stranded if the injector or wiring fails completely.

What Happens If You Ignore P0202?

Ignoring P0202 can turn a simple wiring or injector repair into a much bigger bill. Continuous misfiring can damage the catalytic converter, foul spark plugs, and contaminate engine oil with fuel. Over time, you may see severe power loss, hard starting, and even internal engine wear. Addressing the issue early usually keeps the repair limited to the injector circuit instead of the entire exhaust and ignition system.

Last updated: February 13, 2026

Vehicles Commonly Affected by P0202

P0202 can show up on almost any OBD-II vehicle, but it’s especially common on high-mileage models where engine bay heat and vibration stress the injector harness. You’ll often see this code on:

• Ford: Focus, Escape, F-150, Explorer with inline-4 and V6 engines.
• GM/Chevrolet: Silverado, Tahoe, Malibu, Equinox, and GMC Sierra with V6 and V8 engines.
• Chrysler/Dodge/Jeep: Ram trucks, Grand Cherokee, Charger, and minivans with Pentastar V6 or older V8s.
• Toyota/Lexus: Camry, Corolla, RAV4, Tacoma, and some Lexus V6 models.
• Honda/Acura: Civic, Accord, CR-V, and MDX/Pilot with aging injector harnesses.
• European brands: VW, Audi, BMW, and Mercedes with direct injection systems, where injector connectors sit close to hot cylinder heads.

Regardless of brand, any vehicle with over 100,000 miles and lots of heat cycles is a candidate for injector circuit issues like P0202.