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E-Mark & ECE Lighting Guide: How to Read Headlight and Taillight Markings (HCR, DCR, RL, Arrows, Reference Numbers)
Decode every marking on an ECE-approved lamp: what the E-number really means, why HCR is not "halogen," what the arrow and reference number control, taillight and indicator codes, the R48 rule for DRLs and indicators, and what an E-mark does not guarantee at inspection.
Every approved headlight and taillight in Europe carries a small block of molded codes — a circled E with a number, an approval number, letters like HCR or DCR, sometimes a number like 25. Most owners never read them; inspectors always do. This guide decodes the whole system in plain language: what the E-number really tells you (and what it doesn't), why the "H" in HCR is not short for halogen, how the reference number limits high beams, what the taillight codes mean, and the one DRL-and-indicator rule that's an actual regulation rather than a convention.
The 60-second version
An E-mark (circled E + number) means the lamp was type-approved to a UN ECE regulation by the authority of the country that number identifies — E1 Germany, E4 Netherlands, E9 Spain, E13 Luxembourg — and every E-number is equally valid across all countries that apply the ECE regulations. The letters say which functions were approved: C low beam, R high beam, CR both; an H prefix (HC, HR, HCR) means Class B — the higher performance class used by halogen and LED headlamps — not "halogen"; D (DC, DR, DCR) means gas-discharge/xenon; RL is a daytime running lamp, A a front position lamp, PL a plastic lens. The E-mark molded into the lens is the proof of approval inspectors look for — no paperwork involved; what remains is fitting the lamp correctly: aim, colours, and error-free wiring.
1) Anatomy of an E-mark — the four parts
A typical headlamp marking reads something like ⓔ13 HCR PL 25 05 1234. Broken down:
① Circled E + number — who approved it
The country whose type-approval authority tested and approved the lamp. It identifies the approving authority, not where the lamp may be used — see section 2.
② Function letters — what it's approved to do
C, R, CR, HC, HCR, DC, DCR, RL, A, B/F3, 1, 1a, 1b… Each function on a combined lamp gets its own letters, so a modern headlight typically carries several groups — decoded in section 3.
③ Approval number — which version of the rules
The digits after the mark. The first two digits give the series of amendments of the regulation the lamp was approved to (e.g. "05" = 05 series); the rest is the individual approval number.
④ Extra symbols — arrow, PL, reference number
A horizontal arrow on some headlamps (traffic system), PL (plastic lens) and a number like 12.5, 25 or 30 next to a high-beam approval (the reference value). Each explained in section 4.
2) E-numbers and countries — does it matter which?
No. This is the most common misunderstanding about E-marks: an E9 lamp is not "Spanish-legal" and an E1 lamp is not "more approved" than an E13. The number only says which authority did the testing; the approval itself is recognised by every country applying the UN ECE regulations. Common numbers you'll see:
| Mark | Approving country | Mark | Approving country |
|---|---|---|---|
| E1 | Germany | E11 | United Kingdom |
| E2 | France | E13 | Luxembourg |
| E3 | Italy | E20 | Poland |
| E4 | Netherlands | E24 | Ireland |
| E9 | Spain | E36 | Lithuania |
E13 (Luxembourg) and E4 (Netherlands) appear on a large share of aftermarket lighting simply because their authorities are widely used by certification labs — it says nothing about quality or scope.
3) Headlight function codes — the corrected legend
Headlamp letters follow a simple grammar: C = passing (low) beam, R = driving (high) beam, CR = both in one unit, C/R = both but not usable simultaneously. A prefix tells you the class or technology:
| Code | Meaning |
|---|---|
| C · R · CR | Low beam · high beam · both — Class A headlamp (the lower photometric class; older filament designs). |
| HC · HR · HCR | Low beam · high beam · both — Class B headlamp. The H marks the higher performance class, not the light source: halogen and LED headlamps approved under R112 both carry these letters. An LED headlight marked HCR is correctly marked. |
| DC · DR · DCR | Low · high · both — gas-discharge (HID/xenon) headlamp, approved under R98. |
| HC/R · DC/R | Low and high beam that cannot be lit simultaneously (the slash is the giveaway). |
| Mixed, e.g. DCHR | Combined units list each function: DCHR = xenon low beam + Class B high beam in one housing. |
| C-BS · CR-BS · WCR-DS… | Symmetrical passing-beam headlamp (flat cutoff), approved under R113 — its own category with its own codes: the S marks symmetrical, the letter before it the class (A–E). A flat-beam lamp marked this way is correctly marked, not a headlamp "missing" its HCR. |
| RL | Daytime running lamp (R87). |
| A | Front position lamp / sidelight (R7). |
| B · F3 | Front fog lamp (R19) — B on older approvals, F3 on current ones. |
| 1 · 1a · 1b | Front direction indicator categories (R6) — the number depends on the indicator's distance from the low beam. |
| PL | Plastic lens material — the lens passed the abrasion, weathering and chemical tests required for polycarbonate. |
| → / ↔ (if present) | Traffic-system symbol on some headlamps. No arrow is the normal right-hand-traffic configuration — read it together with the passing-beam code, section 4. |
4) The arrow, the reference number, PL and R149
The arrow — read it together with the headlamp code
For an asymmetric passing-beam approval (the HC/HCR and DC/DCR families), the traffic-direction arrow identifies which traffic system the headlamp is approved for. No arrow is the normal right-hand-traffic configuration; a single horizontal arrow identifies a left-hand-traffic-only headlamp; a double-headed arrow (↔) identifies a headlamp approved for both traffic systems.
Don't judge traffic suitability from the visible cutoff alone. Symmetrical (flat-beam) headlamps are a separate UN approval category — Regulation 113 — with their own function codes, recognisable by the S suffix and a class letter: C-BS, CR-BS, WCR-DS and so on. A combined assembly can also carry arrows belonging to other functions, so always read the passing-beam code and its associated arrow together.
The reference number — high-beam budget
A number such as 12.5, 17.5, 25 or 30 next to a high-beam approval is not a brightness rating — it's an installation value. The rule (R48) is that the reference numbers of all high beams that can be lit at the same time must add up to no more than 100, which corresponds to a maximum of 430,000 cd on the vehicle. A pair of 30s is 60; add auxiliary driving lamps and the budget matters.
PL — plastic lens
Almost every modern lamp has a polycarbonate lens. PL certifies that the lens material passed the required abrasion, weathering, humidity and chemical-resistance tests — the difference between a lens that stays clear and one that yellows in three summers.
R149 — the new mark you'll increasingly see
Since late 2021, new headlamp approvals are issued under UN R149 ("Road Illumination Devices"), which merged R112, R98, R113, R123 and R119 into one technology-neutral regulation. Lamps approved under it carry a differently structured mark, sometimes a compact "unique identifier" code instead of the classic layout. Existing R112/R98 approvals remain fully valid — an older-style mark isn't an expired one.
5) Taillight and indicator codes
The same grammar applies at the rear. A taillight typically carries several groups on its lens:
| Code | Meaning |
|---|---|
| R · R1 · R2 | Rear position lamp (tail light), R7 — variants by intensity. |
| S1 · S2 | Stop lamp, R7 — S1 single-level, S2 variable-intensity. |
| F | Rear fog lamp, R38 — red, and required on the driver's side or centre in Europe. |
| AR | Reversing lamp, R23 — white only. |
| 2a · 2b | Rear direction indicator categories, R6 — amber; 2b variable-intensity. |
| 5 · 6 | Side repeater indicator categories, R6. |
| L | Rear registration plate lamp, R4. |
| IA | Rear retro-reflector class, R3 — the red reflector must be present even on an LED taillight. |
Indicator flash rate is regulated too: 90 ± 30 flashes per minute (60–120). Faster than that after a lamp swap is "hyper-flash" — a load-monitoring reaction, covered in our CANBUS & hyper-flash guide.
6) DRL + indicator: the actual rule
You'll often read that "DRLs should dim when indicating." The regulation (UN R48, §6.19.7) is more precise than that, and worth knowing exactly because inspectors do:
- DRL and indicator share the same light source or surface ("reciprocally incorporated"): the DRL on that side must switch off for the whole time the indicator is active — both the on and off phase of each flash.
- DRL within 40 mm of the indicator: the DRL on that side may switch off or reduce intensity while indicating — permitted, not mandatory.
- DRL more than 40 mm away: no requirement; the DRL may stay lit at full intensity.
The purpose is contrast: an amber signal next to a bright white DRL is harder to read at a glance. Well-designed LED headlights with a DRL bar running past the indicator handle this in the electronics — the DRL segment on the signalling side drops out or dims, and returns the moment the indicator stops.
7) Fitted correctly — the other half of the inspection
The E-mark answers the first question an inspector has — is this an approved lamp? — and it answers it on the lens itself: the molded marking is the proof, and no certificate or paperwork is asked for. The second question is whether the approved lamp is fitted and working correctly on the car, and that's where the practical checks live:
- Aim within the tolerance band, no light above the cutoff — see our aiming guide.
- Colours and wiring right — white front, amber indicators, red rear — and indicators flashing at 60–120/min with no bulb-out warnings.
- High-beam reference numbers totalling no more than 100 if auxiliary lamps are added.
- Every required function present and working — rear reflectors, rear fog, DRLs that come on with the ignition.
- Leveling operating where fitted, with no lighting faults on the dash.
- The lamp used in its everyday configuration: on switchable-DRL headlights the white mode is the daily setting, and the additional colours are a styling option — use as intended in line with local expectations. The full logic is in our CSL DRL guide.
8) Inspection checklist: what testers look at
Whether it's TÜV, MOT, ITV, Contrôle Technique or Techninė apžiūra, the lighting check covers the same ground. Five minutes before the appointment saves the re-test:
- Markings present and legible — the circled E and function letters molded on every lamp. That's what the tester reads; no documents are requested.
- Low-beam aim within the band, no light above the cutoff. Pre-check with the 1% wall method.
- Colours: white front, amber indicators, red rear, white reversing, red rear fog.
- Indicator rate 60–120 per minute, both sides, no bulb-out warnings.
- DRL behaviour — on with ignition, and giving way to the indicator where the design requires it.
- Leveling working where fitted; no "adaptive headlight" faults on the dash.
- Lenses clear and dry — see condensation below.
On aim, briefly: the low-beam cutoff should sit about 1 cm lower for every metre of distance to a wall (7.6 cm at 7.6 m), with the exact value for your car printed on the aiming sticker under the hood — usually 1.0–1.5%. The full method, the sticker logic, and what beam testers measure are in the headlight aiming guide.
9) Condensation vs moisture — which is a defect?
Normal: light misting that clears
Every headlamp breathes through vents; a fine, even fog after a cold night or a car wash that clears within minutes of the lights running is physics, not a fault. Inspectors don't fail it, and it doesn't damage anything.
Defect: droplets and pooling that stay
Visible droplets, water lines, or pooling in the lower corner that persist for days mean the seal has failed. That moisture corrodes connectors and kills LED and control modules — the failure chain behind most "one side stopped working" stories. Document it and act on it.
10) Downloads — print and keep in the glovebox
ECE Code Decoder (PDF)
One-page reference: E-numbers, headlamp and taillight function codes, reference numbers.
DownloadPre-Inspection Lighting Checklist (PDF)
Tick-box sheet covering markings, colours, indicator rate, DRL behaviour, aim and condensation.
DownloadHeadlight Aiming Template (PDF)
Wall-marking grid for 7.6 m and 5 m setups with the drop conversion table.
Download11) FAQs — E-marks and ECE lighting
What does the E-mark on a headlight mean?
Does it matter which country's E-number a lamp has?
Does HCR mean the headlight is halogen? My LED headlight says HCR.
Does an E-mark make the headlight legal on my car?
What is the reference number (12.5, 25, 30) on a headlight?
Do DRLs have to switch off when the indicator is on?
Is condensation inside a headlight a defect?
Are ELERON headlights E-marked?
Markings read — now the two things inspectors measure
An approved lamp still needs correct aim and error-free wiring. The two guides below cover exactly that; the identification guide helps if you're not sure which factory headlights your BMW has to begin with.
© Eleron Lights — Lighting built for clean output, tidy fitment, and real-world usability. More articles.
