What does fault code P0261 mean?

The control module has detected a fault in the Cylinder 1 Fuel Injector (P0261). The signal is below the lower threshold, typically from a short to ground or an internally shorted sensor. The fault is isolated to cylinder 1, positioned closest to timing drive (reference cylinder). This directly impacts individual cylinder volumetric efficiency, firing synchronization, and dedicated harness branch loading. Measurements: • Cylinder 1 Injector – Coil Resistance (Resistance (Ω)): 11.5 - 15.5 Ω (port) / 0.5 - 3.0 Ω (direct injection) [Condition: Connector disconnected at 20°C (cylinder 1)] • Cylinder 1 Injector – Injection Pulse at 0° crank angle (Signal (ms)): 2.5 - 4.5 ms idle / 1.5 - 20 ms under load [Condition: Engine running] • Cylinder 1 Injector – Supply Voltage (Voltage (V)): 11.8 - 14.4 V (port) / up to 65 - 90 V boost (direct) [Condition: Ignition ON / engine running] Oscilloscope: Scope the control side for Cylinder 1 Injector. The trace must show pull-down to < 0.2 V at open, flat saturation, and an inductive spike (40 - 90 V) phase-offset to 0° crank angle. (Scale: 1 ms/div, 20 V/div)

What are the symptoms of fault code P0261?

Sensor signal is pegged at the lower voltage limit (0 V / ground) Noticeable idle shudder at start-up; cam/crank synchronization directly impacts reference cylinder 1. Check Engine Light (MIL) illuminated Possible drivability or power reduction Risk of failing an emissions inspection

What causes fault code P0261?

Most likely: Short to ground on the signal wire or an internal short circuit within Cylinder 1 Fuel Injector Timing drive harmonic zone (cylinder 1): Front reference cylinder exposed to cyclic vibrations from timing belt or chain drive and oil mist from front crank seal. Plenum entry intake pulse: Cooler incoming charge air at the front manifold runner creates cold-start localized lean transients on cylinder 1. Channel A: Verify dedicated wiring pins and signal pair for circuit A against the schematic. Likely: Chafed or pinched wiring harness along the signal path to Cylinder 1 Fuel Injector Possible: Internal mechanical wear or carbon deposits inside Cylinder 1 Fuel Injector Rare: Defective internal output driver or reference circuit in the control module for Cylinder 1 Fuel Injector

How do you fix fault code P0261?

Compare signal voltage and resistance between circuit A and companion circuit B at module connector. Swap component on cylinder 1 over to cylinder 2 and clear DTCs to confirm if the fault follows the part. Inspect front timing cover wiring harness routing for mechanical rubbing against accessory belt tensioner pulleys. Measure signal wire resistance to chassis ground with connector unplugged (must exceed 10 kΩ; low reading confirms short to ground). Verify loaded supply voltage and harness terminal pins at Cylinder 1 Fuel Injector. Check circuit continuity and ground-side voltage drop (< 0.05 V) for Cylinder 1 Fuel Injector. Perform fuel rail pressure-drop / balance test to identify leaking, stuck, or clogged injectors. Mechanic tip: Pro-tip for cylinder 1: Cylinder 1 is the primary sync reference. Always scope cam and crank phase correlation if the DTC recurs after replacing the component.

Standard EOBD

P0261 - Sylinder 1 drivstoffinjektor

Q: What are the symptoms of fault code P0261?

Sensor signal is pegged at the lower voltage limit (0 V / ground) Noticeable idle shudder at start-up; cam/crank synchronization directly impacts reference cylinder 1. Check Engine Light (MIL) illuminated Possible drivability or power reduction Risk of failing an emissions inspection

Q: What causes fault code P0261?

Most likely: Short to ground on the signal wire or an internal short circuit within Cylinder 1 Fuel Injector Timing drive harmonic zone (cylinder 1): Front reference cylinder exposed to cyclic vibrations from timing belt or chain drive and oil mist from front crank seal. Plenum entry intake pulse: Cooler incoming charge air at the front manifold runner creates cold-start localized lean transients on cylinder 1. Channel A: Verify dedicated wiring pins and signal pair for circuit A against the schematic. Likely: Chafed or pinched wiring harness along the signal path to Cylinder 1 Fuel Injector Possible: Internal mechanical wear or carbon deposits inside Cylinder 1 Fuel Injector Rare: Defective internal output driver or reference circuit in the control module for Cylinder 1 Fuel Injector

Q: How do you fix fault code P0261?

Compare signal voltage and resistance between circuit A and companion circuit B at module connector. Swap component on cylinder 1 over to cylinder 2 and clear DTCs to confirm if the fault follows the part. Inspect front timing cover wiring harness routing for mechanical rubbing against accessory belt tensioner pulleys. Measure signal wire resistance to chassis ground with connector unplugged (must exceed 10 kΩ; low reading confirms short to ground). Verify loaded supply voltage and harness terminal pins at Cylinder 1 Fuel Injector. Check circuit continuity and ground-side voltage drop (< 0.05 V) for Cylinder 1 Fuel Injector. Perform fuel rail pressure-drop / balance test to identify leaking, stuck, or clogged injectors. Mechanic tip: Pro-tip for cylinder 1: Cylinder 1 is the primary sync reference. Always scope cam and crank phase correlation if the DTC recurs after replacing the component.

Relatert:Sylinder 1 drivstoffinjektor, Ledningsnett og kontakter, Styreenhet (ECM/PCM)

System

Drivlinje (Motor og girkasse)

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Teknisk beskrivelse

Styreenheten registrerer en feil i sylinder 1 drivstoffinjektor (P0261). Signalet ligger under nedre terskel, som regel på grunn av kortslutning mot jord eller en internt kortsluttet sensor. Feilen er isolert til sylinder 1, plassert nærmest kamdriften (referansesylinder). Dette påvirker sylinderens fyllingsgrad og tenningssynkronisering.

Multimeter Målepunkter & Nominelle Verdier

Målepunkt / Komponent	Måletype	Nominelt Målområde	Målevilkår
Sylinder 1 injektor – spolemotstand	Motstand (Ω)	11.5 - 15.5 Ω / 0.5 - 3.0 Ω	Frakoblet ved 20°C (sylinder 1)
Sylinder 1 injektor – pulsbredde ved 0° veivvinkel	Signal (ms)	2.5 - 4.5 ms tomgang	Motor i gang

Sylinder 1 injektor – spolemotstandMotstand (Ω)

Børverdi:11.5 - 15.5 Ω / 0.5 - 3.0 Ω

Frakoblet ved 20°C (sylinder 1)

Sylinder 1 injektor – pulsbredde ved 0° veivvinkelSignal (ms)

Børverdi:2.5 - 4.5 ms tomgang

Motor i gang

Oscilloskop Kurveformanalyse

1 ms/div, 20 V/div

Mål styresiden for Sylinder 1 injektor; spenningsfall ved åpning og induktiv spiss ved lukking.

Mulige årsaker

Kortslutning til jord i signalledningen eller internt i Sylinder 1 drivstoffinjektor

Kamdrevsone (sylinder 1):Mekaniske svingninger fra registerreim eller kjede belaster sylinder 1.

Innsugspuls for sylinder 1:Kaldere luftstrøm ved inntaket gir magrere blanding ved oppstart.

Kanal A:Sjekk dedikert ledningspar for kanal A i modulkontakten.

Gnagd eller klemt ledningsnett fram til Sylinder 1 drivstoffinjektor

Mekanisk slitasje eller sotbelegg i Sylinder 1 drivstoffinjektor

Defekt driver eller referanseutgang i styreenheten for Sylinder 1 drivstoffinjektor

Symptomer

Sensorsignalet ligger låst ved nedre spenningsgrense (0 V / jord)

Tomgangsvibrasjoner ved oppstart; referansesylinder 1 påvirkes direkte.

Motorlampe (MIL) lyser

Mulig redusert kjørbarhet eller effekt

Risiko for underkjent EU-kontroll

Anbefalt tiltak

Sammenlign måleverdier mellom krets A og krets B.

Bytt del fra sylinder 1 til sylinder 2 for å bekrefte feilvandring.

Sjekk ledninger ved registerdeksel for gnissing.

Mål signalens motstand mot jord frakoblet (> 10 kΩ; lav motstand bekrefter kortslutning til jord).

Sjekk matespenning og kontaktstykke ved Sylinder 1 drivstoffinjektor.

Mål kontinuitet og jordspenningsfall (< 0.05 V) for Sylinder 1 drivstoffinjektor.

Utfør trykkfallstest for å avdekke dryppende eller tette injektorer.

Mekanikerens tips

Mekatips sylinder 1: Sylinder 1 er synk-referanse. Mål alltid kam- og veivfase med oscilloskop ved gjentatt feil.

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P02DD

Sylinder 9 injektor offset-innlæring ved maks-grense

Målepunkt / Komponent

Måletype

Nominelt Målområde

Målevilkår

Sylinder 1 injektor – spolemotstand

Motstand (Ω)

11.5 - 15.5 Ω / 0.5 - 3.0 Ω

Frakoblet ved 20°C (sylinder 1)

Sylinder 1 injektor – pulsbredde ved 0° veivvinkel

Signal (ms)

2.5 - 4.5 ms tomgang

Motor i gang