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DTC codes / Jaguar codes / P1000

P1000 · JaguarOBD Systems Readiness Test Not Complete

P1000 on a Jaguar means the engine control module has not yet completed all of its onboard diagnostic readiness monitors since the last battery disconnect or fault memory clear. The computer is not reporting a fault; it is simply telling you that the self-tests required for emissions compliance have not finished running.

SystemPowertrain
Code typeJaguar specific
SeverityLow
Fix difficultyDIY
AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

  • The check engine light may be illuminated because the ECU cannot confirm monitor completion.
  • No drivability symptoms are usually present; the car often runs perfectly normally.
  • The code appears immediately after clearing fault codes or replacing the battery.
  • Emissions testing may be refused because readiness monitors are incomplete.
  • Some Jaguars may show a message on the instrument cluster about emissions system not ready.
  • Remote start or certain convenience features may be inhibited on models that require monitor completion.

Common causes, most likely first

  1. Battery was recently disconnected or replaced, resetting all readiness monitors.
  2. Diagnostic trouble codes were cleared with a scan tool, erasing monitor status.
  3. The vehicle has not been driven through the specific drive cycle required to run all monitors.
  4. A pending fault code is preventing one or more monitors from completing.
  5. Low battery voltage or poor ground connections cause the ECU to reset repeatedly.
  6. Aftermarket tuning or ECU reprogramming has left the readiness status incomplete.
  7. A faulty sensor or component within a monitored system is blocking monitor completion without yet setting a hard code.

How to diagnose and fix it

  1. Verify battery voltage and condition; a weak battery can reset monitors repeatedly.
  2. Check for any stored or pending diagnostic trouble codes that would prevent monitor completion.
  3. Perform the Jaguar-specific drive cycle for the incomplete monitors, usually a sequence of idle, steady-speed, and deceleration phases.
  4. Use a scan tool to view readiness monitor status and confirm which monitors are incomplete.
  5. Repair any underlying faults found in step 2, then clear codes and repeat the drive cycle.
  6. If monitors still will not complete, check ECU grounds and power supply for intermittent drops.
  7. After all monitors are complete, the code will clear itself and the check engine light will extinguish.

Why P1000 is not a real fault

  • P1000 is often mistaken for a hard failure, but it is simply a status code indicating that OBD readiness tests have not finished; it is not a component failure.
  • Many Jaguar owners clear P1000 by driving a complete drive cycle, but the exact cycle varies by model and engine, so consult the factory service information for your specific vehicle.
  • A weak battery or poor ground can cause the ECU to reset and set P1000 repeatedly, even after a long drive, so always load-test the battery first.
  • Some scan tools cannot display Jaguar-specific readiness monitors, leading technicians to assume all monitors are complete when they are not.
  • P1000 can appear alongside other codes that were cleared but not repaired, so always check for pending codes before assuming the vehicle is fault-free.

Can I keep driving with P1000?

It is safe to drive the vehicle normally while P1000 is stored, but you should complete the drive cycle to allow monitors to run. Avoid clearing codes again until you have verified there are no underlying faults, as this will restart the process.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Jaguar vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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