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Severity: Moderate Code type: Generic (all makes)

P0207 Code: Injector Circuit / Open – Cylinder 7

The ECU lost normal control of injector 7, which only exists on V8 and larger engines.

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: 3/5 – Moderate3/5

Severity: Moderate

Meaning
Injector Circuit / Open – Cylinder 7
System
Fuel & Air Metering · Powertrain
Safe to drive?
With caution
Typical repair cost
$20–$1,800
DIY difficulty
Moderate

Only engines with eight or more cylinders have an injector 7, so P0207 narrows things down right away: GM, Ford and Chrysler V8s, and the V8s in Audi, BMW and Mercedes models. For every firing the ECU switches injector 7 on, then looks for the current build-up and the inductive spike when it switches off; if either is missing, or the control line sits at the wrong voltage between pulses, the circuit is flagged. Cylinder 7 is the rear cylinder on the driver's side on GM and Hemi V8s, third back on the driver's side on Ford V8s, and third on the left bank on most German V8s. If a six-cylinder reports P0207, suspect wrong ECU software or a scan tool set to the wrong engine before touching wires.

Can I keep driving? A V8 running on seven cylinders is drivable at light load, but don't tow. If the engine floods, starts hard when hot or the oil smells of fuel, stop driving: a control wire shorted to ground can hold injector 7 open.

How to read P0207

How to read P0207P10223074
  1. P Powertrain
  2. 0 Generic (SAE)
  3. 2 Fuel & air (injector circuit)
  4. 07 Specific fault

Symptoms

  • Lopey, uneven idle that feels like a big cam, worst in Drive at a stoplight
  • P0307 misfire logged alongside, with cylinder 7 misfire counts climbing
  • Lean code on the bank carrying cylinder 7: P0171 on GM and Hemi engines, P0174 on Ford and most German V8s
  • Noticeable loss of pull when towing or merging onto the highway
  • Rarely, with a short to ground: hard hot starts, fuel smell or fuel-diluted oil

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Injector 7 connector loose or corroded at the back of the engine, the hardest one to see after intake or plug work 24%
  2. Open coil in injector 7 22%
  3. Harness damage where the driver's-side injector harness wraps around the rear of the intake near the firewall 18%
  4. Earlier repair left a pinched harness or unlatched plug, typical after intake manifold removal 14%
  5. ECU driver 7 failure or a poor ECU ground 12%
  6. Control wire shorted to ground, which can hold the injector open and flood the cylinder 10%

Diagnosis step by step

Diagnostic flow: P02071Confirm the engine and cylinder 7position2Run a cylinder cut test3Measure the whole circuit from theECU end4Check the control wire for shorts5Look at the rear connector, don'tjust feel for it6Verify under load

  1. Confirm the engine and cylinder 7 position

    GM and Hemi V8: driver's side, last cylinder toward the firewall. Ford V8: driver's side, third from the front. Audi, BMW and Mercedes V8: left bank, third from the front. If the vehicle only has six cylinders, have the ECU software and scan tool setup checked first.

    Tools: Flashlight

  2. Run a cylinder cut test

    Many scan tools can disable injectors one at a time at idle. Cutting a healthy cylinder drops rpm noticeably; cutting injector 7 should change nothing if its circuit is really dead. That confirms the code before anything comes apart.

    Tools: OBD-II scanner

  3. Measure the whole circuit from the ECU end

    Battery disconnected, ECU connector unplugged: measure from the injector 7 control pin to the injector feed with the injector still connected. You should see the injector's own resistance plus a fraction of an ohm. OL means an open somewhere in wire, connector or coil; split the circuit at the injector plug to find which.

    Tools: Multimeter

  4. Check the control wire for shorts

    With the ECU and injector both unplugged, check the control wire to ground and to battery positive. It must read open to both. A short to ground can hold the injector open; a short to power burns out the ECU driver, so fix the wire before fitting a new ECU.

    Tools: Multimeter

  5. Look at the rear connector, don't just feel for it

    Remove the engine cover or ducting so you can see the injector 7 plug. Check that the lock is engaged, the terminals aren't spread and the seal is intact. On a 5.7 Hemi the injectors sit under the intake manifold, so plan for a gasket if you need to go further.

    Tools: Flashlight, Screwdriver

  6. Verify under load

    Clear codes and road test with a hill or a heavy load while watching cylinder 7 misfire counts and bank fuel trims. Trims should settle within about ±10% and the misfire counter should stay at zero.

    Tools: OBD-II scanner

Where the parts are

Ignition: coils and spark plugs per cylinder – P02071234567
Ignition: coils and spark plugs per cylinder
  1. 1Ignition coil
  2. 2Spark plug
  3. 3Fuel injector
  4. 4Camshaft sensor
  5. 5Crankshaft sensor
  6. 6Engine computer (ECM)
  7. 7Intake manifold

Repair options & costs

RepairDIY?Estimated cost
Reseat or replace the injector 7 connector Yes $20–$200
Repair harness at the rear of the intake No $200–$600
Replace injector 7 (fuel rail on top, e.g. GM small-block) No $220–$650
Replace injector 7 with intake manifold removal (e.g. Hemi) No $450–$950
ECU replacement and programming No $700–$1,800

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Notes by brand

Field data

Chevrolet 2 Malibu, Silverado 1500

Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.

Emissions / smog test impact

Will fail

With P0207 active the check engine light stays on, which fails an OBD-II emissions inspection. After the fix, the misfire and fuel system monitors have to run again, which usually takes a few days of mixed driving.

Frequently asked questions

Can cylinder deactivation cause P0207?

No. GM and Hemi engines shut injector 7 off on purpose in four-cylinder mode, and the ECU pauses its circuit check while they're off. A stuck deactivation lifter causes a P0307 misfire, not a circuit code, so P0207 still points at wiring, injector or driver.

Why is my engine flooding with P0207?

A control wire shorted to ground or an injector with an internal short can let fuel flow nonstop. Stop cranking, pull the injector fuse or relay and have it towed; forcing an engine to turn over on liquid fuel can bend a connecting rod.

My truck has a V6 but shows P0207. How?

It shouldn't happen. Make sure the scan tool is set to the correct engine, then have the ECU part number and software verified. A wrong or corrupted calibration can report circuits your engine doesn't have.

Is injector 7 harder to replace than the others?

Usually. It sits at the back of the engine near the firewall. On GM small-blocks it's still reachable from above; on engines with the rails under the intake, the manifold has to come off, which roughly doubles the labor.

Sources