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P0204 on Subaru: Symptoms, Causes & Fix

Injector Circuit Malfunction - Cylinder 4

Official technical diagnostic wire for fault code P0204 specifically affecting Subaru vehicles (Outback, Forester, Crosstrek, WRX, Ascent).

Sensor Voltage Ref
0.1V – 5.0V Ref
Subaru Factory Standard
CAN Bus Speed
500 kbps CAN-FD
ISO 15765-4 Diagnostic Bus
Drivability Status
Not Recommended
Critical urgency level
Est. Repair Cost
$150 - $550 (DIY: $40 - $180)
Parts & Labor DIY
Model-Specific Diagnostic Wires

Select Your Subaru Model for P0204:

5 Models Available
Subaru Outback2020–2026
Subaru OutbackSUV • 2.5L Boxer-4 (FB25D 182HP) / 2.4L Turbocharged Boxer-4 (FA24F 260HP XT)
P0204 Fix & DLC Location
Subaru Forester2020–2026
Subaru ForesterSUV • 2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD)
P0204 Fix & DLC Location
Subaru Crosstrek2021–2026
Subaru CrosstrekSUV • 2.0L Boxer-4 (152HP) / 2.5L (182HP) / 2.0L PHEV Plug-In Hybrid (149HP)
P0204 Fix & DLC Location
Subaru WRX2022–2026
Subaru WRXSedan • 2.4L Turbocharged FA24F Boxer-4 (271HP WRX / 350HP STI)
P0204 Fix & DLC Location
Subaru Ascent2020–2026
Subaru AscentSUV • 2.4L Turbocharged DOHC Boxer-4 (260HP / 277 lb-ft torque)
P0204 Fix & DLC Location

1. Common Symptoms on Subaru Vehicles

When Subaru Engine Control Modules (ECM) trigger fault code P0204, drivers typically report:

Flashing CEL on Subaru Powertrains
Engine vibration and sputtering on Subaru Powertrains
Sluggish acceleration on Subaru Powertrains
P0304 code on Subaru Powertrains

2. Root Causes on Subaru Engines

Historical diagnostic claims across Subaru engines point to the following failure distribution:

55%
Faulty Cylinder 4 fuel injector (Subaru OEM Part)
25%
Broken wiring harness (Subaru OEM Part)
12%
Loose connector lock (Subaru OEM Part)
8%
ECM driver fault (Subaru OEM Part)

3. Step-by-Step Fix Protocol for Subaru

01
Check Injector 4 Resistance

Measure resistance across pins (12–16 ohms). on Subaru engines.

Required Tool: Multimeter
02
Verify Signal with Noid Light

Check that ECM pulse reaches the connector. on Subaru engines.

Required Tool: Noid Light
03
Replace Cylinder 4 Injector

Replace the faulty injector with OEM unit. on Subaru engines.

Required Tool: Socket Set, O-ring Lube
04
Clear Codes and Test

Clear DTC memory and confirm smooth operation. on Subaru engines.

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Subaru (P0204)

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Direct-Fit Replacement Part

Subaru OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for Subaru.

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Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

$29.99 Prime
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BlueDriver Bluetooth Pro OBDII Scan Tool

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Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

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4. Subaru P0204 Frequently Asked Questions

What does code P0204 mean on a Subaru?

On Subaru vehicles, P0204 indicates that the Engine Control Module (ECM) detected injector circuit malfunction - cylinder 4. This typically points to Faulty Cylinder 4 fuel injector or Broken wiring harness.

Can I continue driving my Subaru with code P0204?

No. Cylinder 4 is disabled, causing rough running and unburned fuel delivery issues. Because this code carries a Critical severity rating on Subaru powertrains, we recommend scanning live data values promptly to prevent secondary damage.

How much does it cost to fix code P0204 on a Subaru?

Estimated DIY parts cost ranges from $150 - $550 (DIY: $40 - $180), while professional shop repairs at an authorized Subaru dealership or independent specialist typically range from $180 to $380 including diagnostic labor.