# EVCS N-303 issue ( 7m cable // 5m cable ) **URL:** \ **Category:** EVCS\ **Tags:** expert, cerbo\_gx\ **Created:** [29 August 2026 15:59 UTC](https://community.victronenergy.com/t/evcs-n-303-issue-7m-cable-5m-cable/62290 "2026-08-29T15:59:25Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![harrix](https://avatars.discourse-cdn.com/v4/letter/h/85e7bf/32.png) [@harrix](https://community.victronenergy.com/u/harrix)\ **Post date:** [29 August 2026 15:59 UTC](https://community.victronenergy.com/t/evcs-n-303-issue-7m-cable-5m-cable/62290/1 "2026-08-29T15:59:25Z")
My charging station (EVCS) is running the latest firmware version (v2.08/5.2). When I switch from charging a Tesla (with its 7 m cable) to charging a Renault R5 (with a 5 m cable), the charging station displays error code N-303 with the 7 m cable. However, if I use the R5’s 5 m cable to charge the Tesla, the charging station recognises it. Both cables used to work. Sometimes simply unplugging and reconnecting the Tesla’s cable gets it working, but not consistently. It would be great if the CP calibration menu were available again in the web interface. Are other users experiencing this same issue, where the car is not recognised after switching between two electric vehicles? ---
**Author:** ![Nicolas](https://avatars.discourse-cdn.com/v4/letter/n/67e7ee/32.png) [@Nicolas](https://community.victronenergy.com/u/Nicolas)\ **Post date:** [31 August 2026 21:49 UTC](https://community.victronenergy.com/t/evcs-n-303-issue-7m-cable-5m-cable/62290/2 "2026-08-31T21:49:33Z")
Hello @harrix. You can bring the CP calibration button back if you disable CP auto-calibration. To do that, write `0` to EVCS Modbus TCP register `5133`. Can you do that? If not, I can do it remotely, but for that you also need to have a GX device in your installation and invite me by email. ---
**Author:** ![maryusmm97](https://avatars.discourse-cdn.com/v4/letter/m/3e96dc/32.png) [@maryusmm97](https://community.victronenergy.com/u/maryusmm97)\ **Post date:** [2 September 2026 08:20 UTC](https://community.victronenergy.com/t/evcs-n-303-issue-7m-cable-5m-cable/62290/3 "2026-09-02T08:20:37Z")
can you please help me as well with enabling the manual CP calibration? ---
**Author:** ![Nicolas](https://avatars.discourse-cdn.com/v4/letter/n/67e7ee/32.png) [@Nicolas](https://community.victronenergy.com/u/Nicolas)\ **Post date:** [2 September 2026 09:23 UTC](https://community.victronenergy.com/t/evcs-n-303-issue-7m-cable-5m-cable/62290/4 "2026-09-02T09:23:43Z")
Sure. Please send me a PM with your installation ID. ---
**Author:** ![harrix](https://avatars.discourse-cdn.com/v4/letter/h/85e7bf/32.png) [@harrix](https://community.victronenergy.com/u/harrix)\ **Post date:** [2 September 2026 18:57 UTC](https://community.victronenergy.com/t/evcs-n-303-issue-7m-cable-5m-cable/62290/5 "2026-09-02T18:57:57Z")
Hello Nicolas. Regarding the topic of reactivating the CP menu, do you just need the installation ID? The answer to the question of whether I have a Cerbo GX is yes. However, I haven’t found where I can send you a private message. Kind regards, Patrice ---
**Author:** ![Nicolas](https://avatars.discourse-cdn.com/v4/letter/n/67e7ee/32.png) [@Nicolas](https://community.victronenergy.com/u/Nicolas)\ **Post date:** [3 September 2026 14:02 UTC](https://community.victronenergy.com/t/evcs-n-303-issue-7m-cable-5m-cable/62290/6 "2026-09-03T14:02:52Z")
Ok, I’ll send you a PM. ---
**Author:** ![EdwinHout](https://avatars.discourse-cdn.com/v4/letter/e/71c47a/32.png) [@EdwinHout](https://community.victronenergy.com/u/EdwinHout)\ **Post date:** [7 October 2026 13:55 UTC](https://community.victronenergy.com/t/evcs-n-303-issue-7m-cable-5m-cable/62290/7 "2026-10-07T13:55:33Z")
At a customer with 2 EVCS chargers we added a third. The first two where installed during firmware 2.0 and at the time of installation were CP calibrated with a 10meter Type 2 charging cable. The third EVCS was added with firmware 2.9 and CP calibration was not present any longer and thus our installer encountered N-303 issue and was working the problem for a few hours as he though something was wrong with the charge cable or EVCS internals. I would like to ask Victron to change the CP calibration back OR fix the auto calibration function. If somebody is interested in the Node Red code re-enabling the CP calibration option, let me know. The code injects 0 to the correct register to re-enable the calibration option. ![image](https://europe1.discourse-cdn.com/victron/original/3X/0/7/07635fd912817c3b65aaab48fd20d24daea6df47.png) ![Screenshot 2026-10-07 at 16.19.50](https://europe1.discourse-cdn.com/victron/original/3X/8/e/8ef6081f17ee64a122c80ff0c2e087b5b6a618c1.png)