Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / P1286 — Fuel pulse width in range, but less than expected

P1286 — Fuel pulse width in range, but less than expected

Detailed page for trouble code P1286.

35,619codes
59brands
11,925generic
23,694specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

P1286

LAND ROVER P — Powertrain

Fuel pulse width in range, but less than expected

Brand: LAND ROVER
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Low fuel rail pressure or restricted fuel supply
  • Clogged or partially stuck injectors reducing effective flow
  • Faulty fuel pressure regulator
  • Faulty or out-of-range MAF, MAP, or TPS sensor readings causing incorrect fuel commands
  • Intake air leak (vacuum leak) diluting the mixture
  • ECM/PCM fueling strategy or adaptation issue

Symptoms

  • Check Engine Light (MIL) illuminated
  • Reduced engine power or poor acceleration
  • Hesitation or stumble on acceleration
  • Rough idle or intermittent misfire
  • Longer cranking or hard starting when fuel is low
  • Possible increased fuel trim values (long-term/short-term)

What to check

  • Read stored DTC(s) and freeze frame / live data (fuel pulse width, fuel trims, RPM, load)
  • Visually inspect fuel lines, filter and connectors for leaks or restrictions
  • Measure static and dynamic fuel rail pressure with a gauge
  • Check injector electrical connectors, resistance and operation (noid light or oscilloscope)
  • Scan MAF, MAP, TPS and monitor signals for plausibility against engine conditions
  • Perform smoke test for intake vacuum leaks

Signal parameters

  • Fuel injector pulse width (typical idle ~1–5 ms; light load 2–10+ ms; depends on engine)
  • Fuel rail pressure (typical gasoline systems ~40–60 psi / 275–415 kPa; consult model spec)
  • Short-term fuel trim (STFT) and long-term fuel trim (LTFT) — positive values indicate lean)
  • MAF sensor airflow (g/s) or voltage, MAP (kPa) or vacuum, TPS (%) or volts
  • Injector resistance (ohms) per manufacturer spec
  • Fuel pump current draw (amps)

Diagnostic algorithm

  1. Record freeze-frame and live data; note conditions when P1286 set (RPM, load, temperature).
  2. Verify basic maintenance items: correct fuel level, recent fuel filter service, water or contamination in tank.
  3. Measure static fuel rail pressure with a gauge; compare to specification. Repeat under cranking and running conditions.
  4. Check fuel pump operation and flow rate; inspect/replace fuel filter if suspect.
  5. Test injector electrical supply and driver signals (noid light or oscilloscope). Measure injector resistance and compare to spec.
  6. Perform injector balance/latency or flow testing (professional injector bench or in-vehicle balance test) to identify low-flow injectors.
  7. Scan and validate MAF/MAP/TPS sensor outputs against expected values for RPM/engine load; swap/replace sensors if out of range.
  8. Perform intake system vacuum/smoke test to locate leaks. Inspect PCV/EGR systems for faults.
  9. Inspect fuel pressure regulator and return line for restrictions or leaks; check for excessive fuel return or pressure drop under load.
  10. Verify cam/crank timing and VVT operation; incorrect timing can change fueling requirements and pulse widths.
  11. Check ECM grounds and connector integrity; update ECM software or clear adaptations if recommended by manufacturer.
  12. After repairs, clear codes and road-test under the same conditions that set the code; recheck live data and confirm DTC does not return.

Likely causes

  • Low or inconsistent fuel rail pressure (weak fuel pump, clogged filter)
  • Partially clogged or leaking injectors with reduced flow
  • Faulty fuel pressure regulator or fuel return restriction
  • Incorrect airflow or manifold pressure input (MAF/MAP/TPS)
  • Intake vacuum leak or EGR malfunction causing lean readings

Fault status

⚠️ Status
Fuel pulse width measurable but lower than expected for operating conditions — possible lean fueling, low rail pressure, restricted injectors, sensor or supply fault.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.5 hours

Similar codes

P0171 P0174 P0087 P0191 P0201 P0300
413

Browse 413 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .