Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Readiness Code
The readiness code provides status (Yes/No) of the system having completed all the required monitoring functions or not. The readiness code is displayed with an aftermarket scan tool. The code is a binary (1/0) indicating:
- 0=Test Completed or Not Applicable
- 1= Test Not Complete
A "readiness code" must be stored after any clearing of fault memory or disconnection of the ECM. A readiness code of "0" will be stored (see below) after a complete diagnostic check of all components/systems, that can turn on the "CHECK ENGINE" Light.
The readiness code was established to prevent anyone with an emissions related fault and a "CHECK ENGINE" Light on from disconnecting the battery or clearing the fault memory to manipulate the results of the emissions test procedure (IM 240).
Interpretation of the Readiness Code by the ECM(s) (SAE J1979)
The complete readiness code is equal to "one" byte (eight bits). Every bit represents one complete test and is displayed by the scan tool, as required by CARB/EPA.
- 1 = EGR Monitoring (=0, N/A with BMW)
- 0 = Oxygen Sensor Heater Monitoring
- 1 = Oxygen Sensor Monitoring
- 1 = Air Condition (=0, N/A with BMW)
- 0 = Secondary Air Delivery Monitoring
- 1 = Evaporative System Monitoring
- 1 = Catalyst Heating (=0, N/A with BMW at this time).
- 0 = Catalyst Efficiency Monitoring
Drive the car in such a manner that all tests listed above can be completed (refer to the FTP cycle). When the complete "readiness code" equals "0" then all tests have been completed and the system has established its "readiness". Accessibility of the readiness code is also possible using the DIS/MoDIC.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.