P0203 Cylinder 3 Injector Circuit Malfunction

OBD-II Trouble Code - P0203 - Data Sheet

P0203 - Cylinder 3 injector circuit malfunction.

• Note . This code is the same as P0200, P0201, P0202 or P0204-P0212. In addition to P0203, misfire codes and rich/lean fuel codes can be seen.

What does trouble code P0203 mean?

This Diagnostic Trouble Code (DTC) is a generic transmission code, which means it applies to OBD-II equipped vehicles. Although general, specific repair steps may differ depending on the brand / model.

P0203 means the PCM has detected a malfunction in the injector or the wiring to the injector. It monitors the injector, and when the injector is activated, the PCM expects to see a low or near-zero voltage.

When the injector is off, the PCM expects to see a voltage close to battery voltage or "high". If it does not see the expected voltage, the PCM will set this code. The PCM also monitors the resistance in the circuit. If the resistance is too low or too high, it will set this code.

Possible symptoms

Symptoms of this code are likely to be misfiring and rough engine performance. Bad overclocking. The MIL indicator will also light up.

The symptoms vary from car to car, but the constant is that the Check Engine light comes on after a malfunction is detected. Other symptoms that may occur include:

• Poor fuel consumption
• Works poorly
• Engine stalls while running
• Poor or rich conditions
• Engine misfires

Causes of the P0203 code

The reasons for the engine light code P0203 can be as follows:

• Bad injector. This is usually the cause of this code, but does not rule out the possibility of one of the other causes.
• Open in the wiring to the injector
• Short circuit in the wiring to the injector
• Bad PCM
• Injector out of order or out of order in cylinder 3
• Open or short circuit in wiring harness
• Poor electrical connection

Possible solutions

1. First, use the DVOM to check the resistance of the injector. If it is out of specification, replace the injector.
2. Check the voltage at the fuel injector connector. It should have 10 volts or more on it.
3. Visually inspect the connector for damage or broken wires.
4. Visually check the injector for damage.
5. If you have access to an injector tester, activate the injector and see if it works. If the injector works, you probably have either an open circuit in the wiring or a blocked injector. If you don't have access to the tester, replace the injector with a different one and see if the code changes. If the code changes, then change the nozzle.
6. On the PCM, disconnect the driver wire from the PCM connector and ground the wire. (Make sure you have the correct wire. If you are unsure, do not try) Injector should activate
7. Replace injector

How does a mechanic diagnose a P0203 code?

In all cases, the first step is to check which codes are present in the vehicle. A qualified technician will begin by installing an advanced scanner and reviewing the codes found. Once the codes are found, the freeze frame data is checked against what the car was doing when the code was set. All codes will be cleared and sent for a test drive to check for faults. When the fault is confirmed, a visual inspection of the injector circuit and the injector itself for damage will be carried out.

Next, the voltage at the injector itself will be checked. The scan tool will then be used to monitor injector performance. If all this passes, a noid lamp will be installed in the cylinder 3 injector wiring to check if the voltage pulse is correct.

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

Common Mistakes When Diagnosing Code P0203

Typically, mistakes are made when steps are not followed or entire systems are not tested. To avoid wasting time and money just trying to fix the problem, all steps should be performed in the correct order. Usually the cause of the code P0203 is the injector, but it must be checked before replacement.

How serious is the P0203 code?

With P0203, if the vehicle performs poorly and cannot continue driving, then this is a serious condition that requires the vehicle not to be driven and the code to be repaired as soon as possible. In much less serious cases, the only tangible sign is the Check Engine light coming on.

What repairs can fix code P0203?

• Repair or replacement of wiring harness
• Nozzle replacement 3 cylinders
• ECU replacement
• Fixed connection issues

Additional comments to consider regarding code P0203

Special tools, such as an advanced scanner, may be required to properly diagnose P0203. These advanced scanning tools allow technicians to view much more information than just code, such as real-time performance data and the ability to view injector performance data.

Another tool you might need is the noid light kit. These are tools that give the technician more data than just the presence of voltage. When diagnosing injectors, an important aspect is the voltage pulse that drives the injector. Noid lights are used to determine the correct pulse timing.

P0203 Injector Wiring Fault Fix

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