P0204 medium Severity

P0204: Cylinder 4 Injector Circuit Malfunction

Engine misfire, rough idle, reduced power, poor acceleration

Overview

OBD-II P0204 indicates a malfunction in the fuel injector circuit of cylinder 4, often due to wiring faults, injector failure, or PCM driver issues.

Common Symptoms

  • Check Engine Light illuminated
  • Rough idle or engine shaking
  • Engine misfire or hesitation
  • Reduced acceleration or power
  • Increased fuel consumption

Most Common Causes

Faulty fuel injector for cylinder 4 high

Injector internal failure or stuck condition often triggers P0204.

Open or short in injector wiring harness high

Damaged, chafed, or disconnected wiring is frequently reported.

Poor or corroded connector at injector medium

Connector corrosion or loose contacts can cause intermittent faults.

PCM/ECM driver circuit failure medium

Internal driver transistor failure in control module is less common but documented.

Diagnostic Steps

  1. Verify and record P0204 with scan tool, then clear and retest
    Expected: Code returns consistently under similar conditions
    Interpretation: Confirms persistent fault versus transient trigger
  2. Visually inspect wiring and connector at cylinder 4 injector
    Expected: No broken wires, corrosion, or loose pins
    Interpretation: Damage here likely cause; repair wiring/connector
  3. Measure injector resistance with multimeter
    Expected: Resistance within OEM spec
    Interpretation: Out-of-spec resistance suggests bad injector
  4. Check for presence of proper voltage at injector connector
    Expected: Battery voltage at reference pin when key on
    Interpretation: No voltage indicates wiring/PCM issue
  5. Use noid light or scan tool to check injector pulse
    Expected: Injector receives control pulse when engine cranking
    Interpretation: No pulse indicates driver circuit or PCM fault
  6. Swap injector 4 with another cylinder (if feasible)
    Expected: Code moves to new cylinder
    Interpretation: Faulty injector confirmed if code follows

Repair Solutions

Replace faulty injector medium
Estimated Cost: $150 - $450

Cost varies by vehicle and part quality

Repair or replace damaged wiring/connectors medium
Estimated Cost: $50 - $300

Depends on extent of wiring damage

Replace PCM/ECM driver module hard
Estimated Cost: $600 - $1500

Only if diagnostics confirm internal control module failure

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Assuming fuel delivery issues like low pressure without verifying circuit
  • Misattributing general misfire codes (P0304) without checking P0204 circuit specifics

Frequently Asked Questions

Can you explain the meaning of P0204?

Cylinder 4 Injector Circuit Malfunction is the standard definition for P0204. This diagnostic code is triggered when the ECU detects a problem in the Fuel System.

How serious is the P0204 code?

With a severity level of medium, engine misfire, rough idle, reduced power, poor acceleration

What happens when the P0204 code is active?

The most typical signs are: Check Engine Light illuminated, Rough idle or engine shaking, Engine misfire or hesitation.

Why is my car throwing a P0204 code?

The most common causes are: Faulty fuel injector for cylinder 4, Open or short in injector wiring harness, Poor or corroded connector at injector.

How much does it cost to fix P0204?

Repair costs depend on the specific failure. A simple Repair or replace damaged wiring/connectors replacement is relatively affordable ($50-$300), whereas a Replace PCM/ECM driver module repair is more expensive, potentially reaching $1500.

Is the P0204 code specific to Nissan?

P0204 is not specific to any one brand. It can appear on Ford, Dodge, Toyota, Honda, Jeep, and other vehicles.

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