C2i Code

I believe there are many bros wondering why is this code so important.
Some people think that it is the "ID" of the injector.

If you refer the service manual, you will find it is simply a calibrated values of the physical injector being build that will be used as initial funtioning specifications needed for the ECU as the initial MDP (Minimum Drive Pulse) for optimum performance/fuel injection.
It is not the "ID" that stored within the injector. The ECU doesn't "comunicate" with injector to verify any value.

Each injector degrades over service period due to contaminants in diesel fuel and carbon build up near the nozzle and this MDP need modification and it is done by the close loop logic build in ECU.

MDP learning to control the very small volume precisely through learning according to getting older injectors.
Learning Conditions:
Vehicle speed > 50 Km/h (over 5 seconds)
Engine speed > 2,500 rpm
Coolant temperature > 75°C
Intake manifold pressure > 0.7 bar
Battery voltage 10 V < MDP < 16 V
Fuel temperature 0 < fuel temperature < 80 °C
Initial MDP learning on each injector 5 seconds

Some people thinking it is ok as long as your serviced injector follow its C2I code position. This is not true especially if you never reset the C2I code/MDP over years. Each MDP value changed over time by ECU. You can't use a modified MDP value for serviced injector. Reason being the modified MDP/injection pulse in the ECU can be too long for the serviced injector, causes too much fuel being injected. ECU detacts excessive fuel being injected, will not perform well or even worst - shut down the engine.

So, for those bros wanted to replace their injectors (even with a new unit), better do it at SC with scan-100 that can reset C2I codes & MDP values for you.

If you replace the internal parts of the injector, you need to recalibrate the injector for a new C2I code.

If a different injector been replaced or changed the nozzle, the C21 value is different, thus the fuel injection is not optimised. ECU will then use the default value that will result in slight throttle delay.

After each injector been serviced, will need to reset MDP value that works like mileage counter. Resetting MDP value and setting C21 code will need Scan 100, so not wise to replace / service injector at external workshop.

Phew~ finally ,Scan 100 no longer needed to do C21 coding ,i had cracked the C21 coding protocol in our rexy, tested on my customized scanner and it works perfectly on rexy...

what......wow....you are genius bro.. glad you buy rexton.

Congrats, another major breakthru for our RextonHub. Hopefully Map Switcher will be a reality soon.

9885 from PG need sifu advise on MDP now only i know everytime u sevice injector the MDP value start from 0 or 1 Kulim SC Bosch scan cannot detect MDP count only can reset C21 my car out from ICU last friday after sevice injector at two places BM and Taiping immedite i drove to another SC using G scan everything ok except injector MDP counts read 1 SC said nothing can be done u must drive until MDP read 5 and above so i drove 4 two days sat and sun . Monday sent to Ssyong SC using scan 100 to scan injector 1 to 4 read 3 no. 5 read 2 SC told me they cannot set MDP u must drive until it reach 10. Currently my car when u accederate no power come in until a new second . Question Is it due to MDP not reach 10 so the car no power during accederate . What can be done . Sifu pls advise . First time it jam at road side Kulim SC suspect diesel mix with kerosin cause injector faulty drain diesel send injectors to Taiping 4 cleaning put it back and drive 4 3 weeks since like ok b4 Betong trip send to Kulim Sc to scan no errors very happy drive to Betong with convoy Friday going no problems except not much power uphill Sunday came back halfway down hill check light up stop and start again light still there nothing can be done since the car can move with min power i drive slowly hopefully can cross the boarder to Malaysian . But it jam again car can start but cannot move none better how hard u press pedal. No choice call other member to take me back Malaysia . Next day i take Kulim SC to Betong to service scan show injector fault grow plug and voltage low . SC use Scan to reset injector and the car can move .i not sure can MDP not reach valve can cause injector faulty or the Taiping injector cleaning not done properly .

Bro 9885,

I have read the service manual. mdp initial value is the c21 code. You can only set the c21 code only. Additional value are learned during closed loop. If you have service the injector and install in the correct location, no coding is necessary. It will change to new value on close loop as it learn during driving.
Is your car back to normal now, after the last reset?

After my injector was serviced at Klang, the C21 code was not reset. But it was installed in same position. Till now more than 50k km later, still going strong. Maybe u need to check that injector again.

Sounds very confusing even after reading several times. Let me clarify

1. You serviced all 5 injectors? What are the issues before you service them and if you did a leaking test on 5 of them before dismantling them?

2. Did the Taiping Injector cleaning provided any test result when the injector return from servicing and what are being replaced? I understand that they has bench test machine to do testing.

3. Are all the same injectors reinstalled back to the same location correctly? Is Leaking Test done after installation?

4. What is the error code for the injector fault? Different error code tell different thing.

5. Grow Plug faulty will not stall a moving Rexton, perhaps it is the Voltage low that stall the car. What was being diagnosed that causing the Voltage low? Not charging or Battery dead?

Poor injectors could still function but with knocking sound and worse case will be engine shaking when accelerate. It could also be loose connection like few of the bros experienced before.

If the same injectors are installed back and the nozzle tip was not replaced, C21 do not need to be re-enter. But even if you changed a new injector or replaced nozzle tip, not entering C21 code will not stall the car. The ECU will use its default code but not spraying at optimum rate, thus you will fill response lagging or lack of power.

MDP is the life counter of the injector after it was being reset. You can connect Bro Husni scanner to the car while driving to read the ECU to see if any difference compared to others. Once Bro Neonlee's custom built scanner is ready, we will be able to reset C21 code without Scan100.

Tq Bro Will check with Kulim SC and let u know