P0203 OBD-II Trouble Code: Injector Circuit Malfunction - Cylinder 3

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0203 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0203 code

P0203 is a diagnostic trouble code (DTC) for "Injector Circuit Malfunction - Cylinder 3". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0203 DIAGNOSTIC Get a fair and transparent estimate upfront

Check Engine Light

P0203 code definition

P0203 is a general OBD2 code that points to a fault in the injector circuit.

  • Note: This code is similar to P0200, P0201, P0202, or P0204-P0212. Misfire codes and rich / lean codes may be seen in addition to P0203.

What the P0203 code means

The P0203 is a diagnostic trouble code that is set when the engine control module (ECM) has detected a fault in the injector circuit for cylinder 3. The ECM looks for a specific range of voltage and resistance from each injector circuit and when the results are found to be out-of-range, a diagnostic trouble code (DTC) will be set.

Once the DTC is set, the car will enable a failsafe mode which prevents further damage to the vehicle. When a failsafe mode is set, it will remain until normal operation is detected or is repaired.

What causes the P0203 code?

  • An ECM that is faulty
  • Injector failing or failed in cylinder 3
  • Open or short found in the wiring harness
  • Electrical connection that is poor

What are the symptoms of the P0203 code?

Symptoms vary from vehicle to vehicle but the constant is the Check Engine Light being illuminated once the fault is found. Other symptoms that may occur include:

  • Poor fuel mileage
  • Running poorly
  • Engine dying while running
  • Lean or rich conditions
  • Engine misfires

How does a mechanic diagnose the P0203 code?

In all cases, the first step will be to check what codes present in the vehicle. A qualified technician will begin by installing an advanced scan tool and seeing what codes are found. Once the codes are found, the freeze frame data will be checked for what the vehicle was doing when the code was set. All codes will be cleared and taken for a test drive to verify the fault. When the fault is verified, a visual inspection will be performed on the injector circuit and the injector to look for any damage.

Next, the voltage will be checked at the injector itself. The scan tool will then be used to monitor injector operation. If all of this passes, a noid light will be installed into the wiring of the cylinder 3 injector to check for the proper voltage pulse.

Lastly, the ECM will be tested according to the manufacturer's specifications.

Common mistakes when diagnosing the P0203 code

Commonly, mistakes are made when steps are not followed or entire systems are not tested. To avoid wasting time and money only to not fix the fault, all steps should be followed in the proper order. Usually the injector is the cause for P0203, but it must be tested before it is replaced.

How serious is the P0203 code?

With P0203, if the vehicle is running poorly and is having trouble staying running, then this is a serious condition which calls for the vehicle not to be driven, and the code to be repaired as soon as possible. In much less serious cases, the only felt symptom is the Check Engine Light being turned on.

What repairs can fix the P0203 code?

Additional comments for consideration regarding the P0203 code

Specialty tools may be needed to properly diagnose P0203, such as an advanced scan tool. These advanced scan tools let technicians view much more information than just the code, such as live action data and the ability to view injector operation data.

Another tool that may be needed is a noid light set. These are tools that give the technician more data than just if voltage is present. When diagnosing injectors, an important aspect is the pulse of voltage that operates the injector. Noid lights are used to determine proper pulse time.

Need help with a P0203 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

P0203
Check Engine Light
trouble codes

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0203 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,696

Rating Summary
3,372
162
42
24
96
3,372
162
42
24
96

Damian

8 years of experience
141 reviews
Damian
8 years of experience
Very professional. Explained the issue in detail, and how to resolve it.
2002 TOYOTA COROLLA - CHECK ENGINE LIGHT IS ON - ORLANDO, FLORIDA

Peter

40 years of experience
1059 reviews
Peter
40 years of experience
Excellent Service and very knowledgeable.
2012 TOYOTA CAMRY - CHECK ENGINE LIGHT IS ON - GILBERT, ARIZONA

Ben

38 years of experience
883 reviews
Ben
38 years of experience
That's the second appointment with Ben Smith. Ben is a really professional and friendly mechanic I've ever met. He arrived just on 9:00am and practiced checking and fixing orderly and cleanly with his knowledge. I believe he has 39 years of mechanic knowledge.
2008 LEXUS RX400H - CHECK ENGINE LIGHT IS ON - HOUSTON, TEXAS

Robert

28 years of experience
500 reviews
Robert
28 years of experience
2003 FORD TAURUS - CHECK ENGINE LIGHT IS ON - SAN JOSE, CALIFORNIA

More related articles

P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP)...

Related questions

Q: Q: Check engine light coming on

Cold weather causes plastic and rubber components to contract. The intake manifold on my truck would expand and contract every winter, setting P0171 and P0174 lean codes. Then finally, this past winter, the manifold cracked. My guess is that you...

Q: intake control solenoid voltage

If the issue persists then it may be possible that the issue is with wiring or computer. Damaged wiring or a faulty computer may compromise power to the solenoid and affect its performance. Many automotive electronic circuits use 12 volts...

Q: Q: We changed our fuel pump

You need to have the fuel pressure regulator and injectors checked for leaking. The fuel pressure regulator is most likely leaking into the intake and causing the excessive fuel to get into the cylinders. I'd suggest getting the vehicle...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com