GF07.16-P-3201IC on-Board Diagnosis (OBD) Common Rail Diesel Injection - Function

GF07.16-P-3201IC On-Board Diagnosis (OBD) Common Rail Diesel Injection - Function
- with CODE (494) USA version

Component Identification:

On Board Diagnosis (OBD) means:
^ Monitoring emission-relevant components and systems during driving
^ Detecting and storing malfunctions
^ Displaying malfunctions by means of a warning lamp (MIL)
^ Transferring detected faults to a scan tool in the workshop via a standardized interface

The following systems are monitored electronically:
^ Exhaust gas recirculation
^ Smooth running control
^ Fuel system
^ CDI control unit and ETC control unit (N15/3)
^ Glow system
^ Intake air path

Readiness code (Readiness code)
This code makes it possible to recognize that test procedures (function chains) relating to fault recognition have been completed. The readiness code detects the following electronic systems:
^ Exhaust gas recirculation (after 15 seconds)
^ Fuel system (after 35 seconds)
^ Smooth running control (after 70 seconds)

The readiness code is set when two driving cycles, including a cold start, have taken place without error.

Warm-up-cycle
Systems that are not constantly monitored are checked only when a warm-up cycle is executed.
One warm-up cycle consists of:
^ Engine start
^ Temperature increase > 4.5 °C
^ Final temperature > 60 °C
^ Engine switched off
^ Run-on for min. 10 s (wait for radiator fan to finish running on)

Driving cycle
One driving cycle consists of:
^ Engine start
^ 35 seconds at idle
^ Engine switched off
^ Processor run-on (wait for cooling fan power down)

Fault recognition
The CDI control unit checks its input and output signals for plausibility and recognizes possible faults.

The following faults and error states are detected:
^ Signals above or below the limit value (open circuits, short circuits, faulty sensor)
^ Plausibility of signals
^ Function chains with faults
^ Fault messages over the CAN data bus (CDI and ETC control unit)

Fault storage
Faults detected are stored in the fault memory of the CDI control unit together with freeze frame data. If the fault is not confirmed in the subsequent driving cycle, it is erased. Emission-relevant faults are always entered, they have a high priority. An emission-relevant fault is erased from the fault memory after 40 fault-free driving cycles.

Consequential faults
If a faulty signal is detected and the corresponding fault code is stored, all the tests in which the signal is required as a comparative parameter, are ended. This ensures that no consequential faults are stored.

Fault freeze frame data/operating conditions
If a fault is detected, the following freeze frame data/operating conditions are saved in addition to the fault code:
^ Vehicle speed
^ Engine speed
^ Coolant temperature
^ Charge air temperature
^ Charge air pressure
^ Engine load status

"CHECK ENGINE" MIL
The engine diagnosis indicator lamp is actuated when the engine starts by the CDI control unit. If there is no fault, the indicator lamp goes off.

If an exhaust-related fault occurs in two consecutive driving cycles, or limp-home mode is activated for the second time, the indicator lamp lights up.
In the event of a fault which could damage the catalytic converter, the engine diagnosis indicator lamp flashes.

The malfunction indicator lamp is switched off automatically by the CDI control unit after 3 or 4 consecutive fault-free driving cycles.

Reading out fault memory
The CDI control unit is linked via the data link connector and the K line to the CAN databus diagnostics. Stored errors can be read out using STAR DIAGNOSIS or a standard read-out device (generic scan- tool) for "ignition ON" or for a running engine via the K-line.

erase fault memory
Stored faults can be deleted using STAR DIAGNOSIS or a standard output device with "Ignition ON" via the K-line.

The fault memory is not erased if the vehicle battery is disconnected.

Computer power-down sequence for CDI control unit
After faults are erased it is necessary to wait until the processor has completed its power-down sequence after the ignition is switched off. This takes approx 30 seconds via the EOBD (without EOBD a maximum of 10 seconds).