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

Our certified mechanics come to you · 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. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 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$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0203 DIAGNOSTIC Get a fair and transparent estimate upfront

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
trouble codes
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0203 code.

SCHEDULE P0203 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(6,114)

Rating Summary
5,655
221
51
35
152
5,655
221
51
35
152

Kevin

24 years of experience
388 reviews
Kevin
24 years of experience
Chevrolet Tracker - Check Engine Light is on - Stone Mountain, Georgia
Kevin was pretty cool! He explained things to me in a way I could understand and was able to offer me some good options to fix my car problems! Very professional and knew his stuff! Excellent experience

JOHNNY

33 years of experience
63 reviews
JOHNNY
33 years of experience
Toyota Camry - Check Engine Light is on - Carmichael, California
Johnny was early, friendly, and thorough! He explained things to me about my car that I had no idea about before! I booked him for a diagnostic appointment and I’m definitely requesting him for a follow-up!

Benji

22 years of experience
184 reviews
Benji
22 years of experience
Jaguar XK - Check Engine Light is on - Phoenix, Arizona
Will absolutely recommend Benjie to all my friends, thorough and knowledgeable. Will have him back fit all future car repairs!

Marco

29 years of experience
124 reviews
Marco
29 years of experience
Kia Soul - Check Engine Light is on - Riverside, California
Marco was great. Cam on time, and explained everything he did. Also gave good recommendation for fixing as the problem has a Kia recall.


More related articles

P0575 OBD-II Trouble Code: Cruise Control Input Circuit
P0575 code means that the control input circuit is suffering from an electrical malfunction often due too a faulty, cruise control switch or wires.
P2219 OBD-II Trouble Code: NOx Sensor Heater Control Circuit Low Bank 2
P2219 code means there is an abnormal reading within the NOx sensor circuit voltage often due too faulty fuel usage or defective sensors.
P0229 OBD-II Trouble Code: Throttle/Pedal Position Sensor/Switch C Circuit Intermittent
P0229 P0229 code definition Throttle/Pedal Position Sensor/Switch C Circuit Intermittent What the P0229 code means P0229 is an OBD-II generic code indicating the throttle/pedal position sensor/switch C circuit has an intermittent input problem causing the sensor input to the engine...

Related questions

Reduced Engine Power message

The "Reduced Engine Power" message is the computer going into failure mode. This mode is to protect you from a possible problem of the throttle getting too high. The mode happens when one of the engine sensors is having a...

P0174, P1004 codes

Hello. From what you describe it would appear that your vehicle is experiencing some sort of fuel or engine performance issues. Code P0174 is for an lean condition in engine bank 2. This can be caused by many things, however...

Check engine light

This can happen occasionally for a variety of reasons and can sometimes be related to things that can change in the atmosphere such as air temperature and density for example. This can impact something like a throttle body temperature sensor....

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 (855) 347-2779 · hi@yourmechanic.com