Monitors, Trips, Drive Cycles and Readiness Codes
Readiness Code
Readiness Code, Reading
Readiness Code, Generating
Function
The readiness code is an 8 digit number block that indicates the results of an emission relevant On Board Diagnostic (OBD).
If a diagnostic for a system (e.g. Exhaust Gas Recirculation -EGR- system) has run through successfully, the respective digit of the number block is set from 1 to 0.
On Board Diagnostics are performed at regular intervals during normal vehicle operation. After repairing an exhaust relevant system, the readiness code should be generated via a road test to ensure that these systems are working according to specifications. If a malfunction is recognized during diagnostic, it is stored in DTC memory.
The readiness code is erased every time DTC memory is erased or when voltage supply is interrupted. DTC memory should therefore only be erased when there are DTCs stored.
Readiness Code, Reading
Prerequisites
• There must not be any DTCs stored in DTC memory --> [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.
Procedure
- Connect diagnostic tester.
- Start engine and let run at idle.
- Under address word 33, select "Diagnostic mode 1: Checking measured values."
- select desired measuring value "PID 01".
- Observe the right 8-digit number block:
If all diagnoses have run through successfully, the 8-digit number block
Specified value: 00000000
must be displayed.
Evaluation PID 01: System status-information (right 8-digit number block:)
If a 1 is displayed instead of a 0 in the 8-digit number block:
Readiness Code, Generating
Prerequisites
• Fuses in E-box (plenum chamber, left) must be OK:
• Battery voltage must be at least 11.5 volts.
• All electrical consumers such as, for example, lights and rear window defroster must be switched off.
• If vehicle is equipped with an A/C system, it must be switched off.
• For vehicles with automatic transmission, selector lever must be in P.
• Ground (GND) connections between engine, transmission, and chassis must be OK.
• Coolant temperature must not be above the maximum of 25° C --> [ Diagnostic Mode 01 - Read Current System Data ] Diagnostic Modes 01 - 09
• There must not be any DTCs stored in DTC memory --> [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09
Procedure
- Connect diagnostic tester.
- Switch ignition on.
- Wait 5 seconds.
- Start engine and let run at idle.
- Perform a road test.
Observe the Safety Precautions that apply to road tests.
The following operating conditions must be met during this road test:
- Bring coolant temperature to at least 85° C via road test --> [ Diagnostic Mode 01 - Read Current System Data ] Diagnostic Modes 01 - 09
- Accelerate vehicle to 100 km/h.
- Drive for 2 minutes in highest gear or in driving mode "D " on a level driving surface at a constant vehicle speed of 100 km/h (no deceleration).
• Vehicle speed --> [ Diagnostic Mode 01 - Read Current System Data ] Diagnostic Modes 01 - 09.
• Engine speed --> [ Diagnostic Mode 01 - Read Current System Data ] Diagnostic Modes 01 - 09.
- Then from 100 km/h, decelerate (do not brake) in highest gear or in driving mode "D" to 900 RPM.
- Park vehicle and let engine run at idle for 40 seconds.
• Accelerator pedal must not be operated during this time.
- Increase engine speed to 1450 to 1750 RPM and hold it as constant as possible for 20 seconds.
- Switch ignition off.
- Switch ignition on again.
- Read readiness code --> [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.
If a 1 is displayed instead of a 0 in the 8-digit number block:
- Repeat complete Procedure.