P0202

Injector Circuit Malfunction - Cylinder 2

P0202 is a generic OBD-II powertrain diagnostic trouble code: Injector Circuit Malfunction - Cylinder 2. It is logged by the engine control unit when the fuel/inj monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P0202
Group
Powertrain
System
Fuel/Inj
Severity
high
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What P0202 means

P0202 is a diagnostic trouble code indicating that the ECM/PCM has detected an electrical malfunction in the fuel injector control circuit for cylinder 2. The control module continuously monitors each injector circuit; when it commands injector 2 to open, it expects a characteristic voltage drop across the solenoid coil. If the observed voltage or current signature falls outside the expected window – due to an open, short, or high resistance – P0202 is stored and the MIL is illuminated.

Like all injector-circuit codes in the P0200 family, P0202 is cylinder-specific. The ECM fires injectors in a sequence determined by the firing order; because the fault is detected and attributed per-channel, the technician can immediately narrow diagnosis to the cylinder 2 circuit without broad system testing. This makes P0202 more actionable than generic misfire codes such as P0300.

The most immediate consequence is that cylinder 2 receives no reliable fuel delivery. The engine compensates to a limited degree with fuel trims on the remaining cylinders, but the misfire is typically felt as vibration at idle and power loss under load. The catalytic converter can be damaged by repeated raw-fuel pulses or, conversely, by running lean on the affected bank.

Diagnosis mirrors P0201: visual inspection of the harness, connector resistance/continuity checks, injector coil resistance measurement, noid-light pulse verification, and injector swap to differentiate injector failure from wiring/ECM faults. On engines where the injector harness runs near hot exhaust components or through tight firewall grommets, wiring damage is a particularly common root cause for the cylinder 2 position.

Common causes

Most-frequently reported root causes when P0202 is logged.

  • 1
    Faulty cylinder 2 fuel injector (failed solenoid coil or internal open)
  • 2
    Damaged, pinched, or corroded wiring in the cylinder 2 injector circuit
  • 3
    Corroded or loose injector connector terminals
  • 4
    Short to ground in the injector signal wire
  • 5
    Open circuit in the injector power supply or ground return wire
  • 6
    Blown injector circuit fuse or failed relay
  • 7
    High injector coil resistance from internal degradation or deposits
  • 8
    ECM/PCM driver channel failure (uncommon)

Symptoms drivers notice

Check engine light illuminated
Engine misfire on cylinder 2, often with code P0302 present
Rough idle and noticeable vibration
Loss of power during acceleration
Increased fuel consumption
Potential fuel smell from exhaust
Hard starting, especially when cold

How to diagnose P0202

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all stored DTCs and freeze-frame data with a scan tool; note any companion misfire codes.
  2. 2
    Inspect the cylinder 2 injector wiring harness visually – look for heat cracks, abrasion, rodent damage, and corrosion at the connector.
  3. 3
    Check relevant fuses and relays for the fuel injection system; replace any that are blown.
  4. 4
    Measure the cylinder 2 injector coil resistance with a multimeter; compare to OEM specification and replace the injector if out of spec.
  5. 5
    Plug a noid light into the disconnected cylinder 2 injector connector and crank the engine; a flashing light confirms the ECM pulse is present; no flash indicates a wiring or ECM fault.
  6. 6
    Perform a continuity and short-to-ground test on the signal wire from the injector connector back to the ECM.
  7. 7
    Swap the cylinder 2 injector with another cylinder, clear codes, and test drive; if the fault code moves to the new cylinder, replace the injector.
  8. 8
    If injector and wiring are confirmed good, inspect the ECM connector and evaluate ECM driver output before replacement.

Related powertrain codes

Frequently asked questions

Is P0202 the same fault as P0201, just on a different cylinder?

Yes, in terms of mechanism and diagnosis. Both describe an electrical fault in a specific injector control circuit. The distinction is only the cylinder affected: P0201 is cylinder 1, P0202 is cylinder 2. Diagnostic steps and likely causes are identical.

Can a clogged injector set P0202?

A mechanically clogged injector that still has correct electrical resistance will not set P0202; it may instead set a misfire code (P0302) or a lean fuel-trim code. P0202 is specifically an electrical/circuit fault, not a flow-rate fault.

Will P0202 damage my catalytic converter?

It can, if the misfire persists. Unburned fuel entering the exhaust stream ignites in the catalytic converter, overheating and damaging the substrate. Repeated or prolonged misfires are a leading cause of catalytic converter failure.

Do I need a dealer scan tool to diagnose P0202?

A generic OBD-II scan tool is sufficient to read the code and live data. However, manufacturer-specific enhanced diagnostics can provide injector activation tests and live current-ramp data that speed up diagnosis, particularly on European and Asian vehicles.

Can I replace just one injector, or do I need to do all of them?

You only need to replace the faulty injector. However, if the vehicle has very high mileage and multiple injectors show elevated resistance or the engine has a history of rough running, replacing the set is worth considering for long-term reliability.

Disabling P0202 in software

RaceTune can permanently disable P0202 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

ECUs with a P0202 disable in our catalogue

Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.

  • Bosch MD1CP004 verified 1 software version

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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