P1000: OBD readiness not complete and why the test fails

P1000 “OBD Systems Readiness Test Not Complete” is used by Ford, Mazda and Jaguar, and it is the friendliest code in the whole catalogue: nothing is broken.

It means the car has not yet finished running its own self-tests since the last time the memory was cleared. Every manufacturer tracks this; Ford simply stores an explicit code for it.

Why the tests need time

The ECU cannot check everything at once. Each monitor has entry conditions that must be met before it will even attempt to run:

• Catalyst monitor — needs a fully warm engine and a sustained steady cruise.
• EVAP monitor — needs a specific fuel level, a cold start, and a stable ambient temperature.
• Oxygen sensor monitor — needs closed loop operation across a range of loads.
• EGR monitor — needs particular load and speed combinations.
• Misfire and fuel system monitors — run continuously, so these complete early.

Some of those conditions occur naturally in a week of ordinary driving. Others, particularly EVAP, can go a fortnight without being met.

Detail on each: OBD readiness monitors explained.

The classic way people fail an emissions test

1. The check engine light comes on a week before the test.
2. The owner clears the code, or disconnects the battery, and the light goes out.
3. They drive straight to the test station.
4. The car fails — not on emissions, but because the monitors read “not ready”.

Most jurisdictions allow at most one or two incomplete monitors. Clearing codes resets them all.

The lesson: never clear codes shortly before an emissions test. More on the timing: clearing codes, when and why and OBD codes and the emissions test.

What actually resets readiness

• Clearing codes with a scan tool.
• Disconnecting the battery.
• A flat battery.
• Some module reprogramming.

Note the third one. A car that has stood for weeks and gone flat has also reset its monitors, which catches people out after a holiday. Related: car after long storage checklist.

Completing a drive cycle

The exact procedure is manufacturer-specific, but a generic cycle that satisfies most monitors looks like this:

1. Cold start. The engine must have sat overnight, with coolant temperature close to ambient. This is not negotiable for several monitors.
2. Idle for two to three minutes with the air conditioning and rear demister on, then off.
3. Accelerate gently to around 40 mph and hold a steady cruise for five minutes.
4. Decelerate without braking, letting the car coast in gear from 40 mph down to about 20 mph. Overrun fuel cutoff is required by several monitors.
5. Accelerate to motorway speed and hold steady for five to ten minutes.
6. Repeat over two or three days of ordinary driving.

Keep the fuel tank between a quarter and three quarters full throughout. The EVAP monitor refuses to run outside that window, and it is the one that most often remains incomplete.

Step-by-step: OBD drive cycle, how to complete.

Which monitor is holding you up

Rather than guessing, read the monitor status directly. Any OBD tool can report which monitors are complete and which are not.

Common stragglers:

Monitor	Why it lags
EVAP	Fuel level and temperature conditions rarely met
Catalyst	Needs a long steady cruise
Oxygen sensor	Needs varied load in closed loop
EGR	Needs specific load points

If one monitor refuses to complete after several days of varied driving, that is meaningful. It usually indicates a genuine fault that is preventing the test from running or from passing — at which point the monitor status has done you a favour by pointing at the system.

If P1000 will not clear at all

Check for stored or pending codes first. A monitor cannot complete if the system it tests has a fault, and a pending code may exist without illuminating the light — see pending vs stored codes.

An incomplete EVAP monitor combined with a pending P0442 or P0456 is telling you the leak test keeps failing rather than not running.

Preparing for a test properly

• Fix any actual fault, then drive normally for a week.
• Do not clear codes in the run-up.
• Check monitor status the day before.
• Keep the tank around half full.

Wider preparation: technical inspection preparation.

Try it on the free tier of the app — pair an ELM327 adapter and read the readiness monitor list before you book the test. Two minutes in the driveway is cheaper than a failed inspection and a second appointment.

Read next

• The comprehensive component monitor: the one that never says “not ready”