P0200 Code: Injector Circuit / Open
The ECU found a fault in the injector control circuits that it can't pin on one cylinder, often a shared feed.
Stop driving
If the engine is misfiring hard, stalling or won't restart, don't drive it: losing several injectors at once can leave you without power in traffic. If it runs smoothly with only the light on, drive gently and directly to a shop.
Safety first · Consult a professional
- Fuel vapor is flammable. No smoking or open flames; work outdoors and fix fuel leaks before driving.
At a glance
Severity: High
- Meaning
- Injector Circuit / Open
- System
- Fuel & Air Metering · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $10–$1,600
- DIY difficulty
- Hard
On a port-injected gasoline engine, every injector gets a switched 12 V feed and the ECU fires it by grounding the other wire. Direct-injection gasoline and common-rail diesel engines are different: the ECU drives both wires, using a boosted supply that can run well above battery voltage. In each case the ECU watches every circuit for missing current, a missing voltage spike or a short. P0200 is the umbrella code. It sets when the fault is in something several injectors share, such as the feed fuse, the main relay, a splice, the injector power stage or the boost circuit inside the ECU, or on controllers that simply don't report by cylinder. Because several cylinders can lose fuel at once, the engine may crank without starting, stall, or run on two or three cylinders. The injectors themselves rarely fail all together, so the answer is nearly always in the wiring, the power supply or the ECU.
How to read P0200
- P Powertrain
- 0 Generic (SAE)
- 2 Fuel & air (injector circuit)
- 00 Specific fault
Symptoms
- Engine cranks but won't start, or starts and dies
- Heavy misfire on several cylinders, check engine light flashing
- Sudden stall while driving, sometimes restarting after a few minutes
- Diesel: limp mode with sharply reduced power
- Several cylinder-specific injector codes stored alongside P0200
- Blown fuse that blows again as soon as it is replaced
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Blown injector fuse or failed EFI/main relay cutting the shared feed to the injectors
- Damaged main injector harness or its inline connector: chafing, heat, rodent bites, corrosion
- ECU injector power stage or boost circuit failed (direct injection, common-rail diesel)
- Poor ECU ground or low voltage during cranking from a weak battery or corroded ground strap
- Aftermarket wiring spliced into the injector circuits: remote start or alarm immobilizer, tuning module, gas conversion
- One injector with a shorted coil dragging down the shared feed or driver
- ECU software fault needing an update
Diagnosis step by step
Read every code and the freeze frame
Note which, if any, cylinder codes P0201 to P0204 are stored with P0200, and look for low system voltage (P0562), main relay (P0685) or ECU internal (P0606) codes. All cylinders affected points to a shared feed or the ECU; two cylinders often means a shared driver pair or one harness branch.
Tools: OBD-II scanner
Check the injector fuse and relay
Find the fuse feeding the injectors in the underhood box, often labeled INJ, EFI, IGN or ECU, and test it on both sides with a meter rather than by eye. Swap the main relay with an identical one, such as the horn relay. A fuse that blows again at key-on means a short to ground on the feed side, often from one shorted injector.
Tools: Multimeter, Pliers
Measure the feed at each injector
On port-injected engines, back-probe the feed pin at every injector connector with the key on or while cranking. You should see within about 0.5 V of battery voltage. No voltage at any injector points upstream to the fuse, relay or splice; no voltage at only one or two points to a break in that branch.
Tools: Multimeter
Check that the ECU is firing the injectors
Plug a noid light into one injector connector and crank. A steady flicker means the ECU is switching that circuit. No flicker on any cylinder, with power present, points to the ECU, its grounds or a missing crank signal, so confirm the scan tool shows rpm while cranking.
Tools: OBD-II scanner, Flashlight
Test ECU grounds and cranking voltage
Measure voltage drop between an ECU ground pin and battery negative while cranking; more than about 0.2 V is too much. Battery voltage should stay above roughly 9.6 V while cranking. Clean and tighten engine-to-body and ECU ground straps.
Tools: Multimeter
Look for add-on wiring
Trace the injector harness for splices, taps or extra relays from remote starters, alarms, tuning boxes or fuel conversions. Unplug or bypass them per their instructions and retest. A cheap tap connector cutting into an injector wire is a classic source of intermittent faults.
Tools: Flashlight, Pliers
Measure each injector's resistance
Port injectors are usually 12 to 16 ohms; direct-injection gasoline injectors about 1 to 3 ohms; diesel solenoid injectors under 1 ohm. Piezo injectors can't be judged with an ohmmeter. One injector far below its siblings can overload the feed or driver: unplug injectors one at a time and see if the fault clears. Never apply battery voltage directly to a direct injector.
Tools: Multimeter
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Replace injector fuse or EFI/main relay | Yes | $10–$90 |
| Repair injector harness or inline connector | No | $120–$450 |
| Remove or correctly rewire aftermarket add-on | No | $80–$300 |
| Replace a shorted injector | No | $150–$700 |
| Repair or replace and program the ECU | No | $600–$1,600 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Volkswagen
On the 1.9 and 2.0 TDI pump-injector (PD) engines, the injector wiring runs inside the valve cover. That internal harness and its connectors are known to crack and short after years in hot oil, causing injector circuit faults and misfires; a new internal harness is the usual fix.
Ford
The 6.0L Power Stroke diesel fires its injectors from a separate fuel injection control module (FICM) that should supply about 48 V. A weak FICM, often damaged by low battery voltage, causes hard starts, rough running and injector circuit codes, so check FICM output voltage before condemning injectors.
Emissions / smog test impact
Will fail
With P0200 stored and the check engine light on, the car fails an OBD-II smog inspection. If the fault also causes misfires, the misfire monitor has to rerun after the repair, so allow some mixed driving before testing.
Frequently asked questions
Why do I get P0200 instead of a cylinder-specific code?
Either the fault is in something all injectors share, such as the feed, a relay or the ECU's power stage, or your ECU simply reports injector faults with one generic code. Read live data and check whether P0201 to P0204 are also stored to narrow it down.
My car cranks but won't start and shows P0200. What should I check first?
The injector fuse and the main relay, then battery voltage while cranking. Those three explain most no-starts with this code, and they cost almost nothing to check before anyone suggests a new ECU.
Can a remote starter, alarm or tuning box cause P0200?
Yes. Anything spliced into the injector wiring adds connections that corrode, loosen or overheat. If the fault appeared after such an install, remove the add-on or have its wiring redone before testing anything else.
Do I need a new ECU?
Only after the feed, grounds, harness and every injector's resistance check out. A shorted injector is a common reason an ECU driver burns out, and fitting a new ECU without replacing that injector can destroy the new one too.
Sources
- SAE J2012 – Diagnostic Trouble Code Definitions
- ISO 15031-6 – Road vehicles, diagnostic trouble code definitions (EOBD)
- Manufacturer public service information (cross-checked)
- Methodology: How We Build Code Pages · Data Sources We Use · Editorial Policy