ME7.5 1.8T
Bosch Motronic ME7.5 (petrol, turbocharged, torque-structured / "Drehmomentstruktur"). Load sensing is primarily MAF-based (Bosch hot-film HFM air-mass meter, signal rl) with a MODELED MAP/speed-density path used for plausibility, boost control and limp-home — it is NOT a primary speed-density system, so calling it a "speed-density/MAF hybrid" is misleading. Same core torque-based software archite
The ECU hardware
Siemens/Infineon C167-derived 16-bit MCU (C167CR/C167CS core, ~20-25 MHz, package marked "SAK-C167"). Program + calibration live in an EXTERNAL parallel NOR flash: AMD/Fujitsu/Spansion 29F400(B) = 512 KB (0x80000) on the mainstream 1.8T boards; some later/variant boards use 29F800 = 1 MB. A separate small SERIAL EEPROM (ST 95040/95080, or 93C86 depending on board rev) holds immobilizer data, component protection/SKC and learned adaptation — it is NOT in the flash .bin. ME7.5 is K-line only (ISO 14230 / KWP2000) for diagnostics and flashing — no CAN flash on this generation. PART NUMBERS: the engine codes here are all LONGITUDINAL, so VAG numbers are Audi-style 8D0/8E0/4B0 907 551 / 906 018 / 909 518 (Bosch 0261 20xxxx); the transverse ME7.5 siblings use 06A/06B 906 032. Always read the actual box/software code off the ECU label and match the DAMOS/XDF to THAT code before editing.
Fuelling and load sensing
Petrol / gasoline, turbocharged (1.8T 20v; K03s stock, K04 for big turbo). Front lambda control is NARROWBAND (Bosch LSH-25 heated switching sensor) — closed-loop to stoich (lambda 1.0) at idle/part-throttle, with a second narrowband post-cat sensor for catalyst monitoring. It is NOT a wideband/UEGO system, so the stock sensor CANNOT verify WOT AFR — all WOT/enrichment tuning must be validated with an external wideband. Fueling goes OPEN-LOOP into commanded enrichment (LAMFA) at WOT/high load.
How this ECU is read and flashed
Read/write over OBD via K-line (ISO 14230 / KWP2000) using a 'dumb' FTDI serial cable — NefMoto Flasher is the free reference (sector-by-sector erase/program so a failed write is recoverable AS LONG AS the boot block survives; checksum-verified transfer; typical read ~5 min, write ~3-4 min). Flashing requires KWP2000 security access (0x27 seed/key 'login'; the ME7 algorithm is public / built into NefMoto). The C167 ME7.5 OBD stack historically had rougher tool support than the ST10 ME7.1.1, so the GUARANTEED full 512KB dump / un-brick path is BOOT MODE: ground the C167 bootstrap pin on the PCB and enter the serial BSL over K-line/RS232 (bench harness) — this bypasses OBD read-protection and recovers a bricked ECU. IMMO: immobilizer secret + component protection/SKC live in the external serial EEPROM (95040/95080/93C86), NOT the flash image — a calibration reflash does not touch immo. component protection on longitudinal cars must match the cluster/SKC. ALWAYS keep a verified STOCK backup (ideally boot-mode-verified) before writing.
Engine codes in this family
- AMB (1.8T 163hp, longitudinal, B6 A4)
- BFB (1.8T 163hp, longitudinal, B6 A4)
- BEX (1.8T 150hp, longitudinal, C5 A6)
- AVJ (1.8T 150hp, longitudinal, C5 A6 / B6)
- BKB (1.8T 163hp, longitudinal, B7 A4 / C5 A6)
- transverse ME7.5 siblings with the same map layout: AWP/AWD/AWW/AWM/AWT/AVC 1.8T; 225hp BAM/APX/AMK (TT/S3)
- NOTE: the early AGU/AEB 1.8T used an EARLIER Motronic, not ME7.5 — verify the ECU before applying this reference
Staging - what each stage really gives
- stage1 - Software only, stock K03s hardware and stock airbox/exhaust. Raise LDRXN/KFMIRL for more load, enrich LAMFA (~lambda 0.80-0.82 WOT), optimize KFZW timing, lift the overboost cut, keep torque-monitor lockstep. Typical: 150-163 hp -> ~190-210 hp, torque to ~270-290 Nm. Peak boost ~1.0-1.1 bar spike / ~0.8-0.9 bar sustained. No injector/MAF change needed; stock narrowband + external wideband to validate.
- stage2 - Stage 1 calibration + bolt-ons: high-flow intake, FRONT-MOUNT intercooler (effectively mandatory to control IAT/knock), high-flow/decat downpipe + cat-back, upgraded diverter valve, sometimes a larger MAF housing (then rescale MLHFM). Recovers heat-soak losses and top-end. Typical: ~205-220 hp, flatter torque, safer EGTs. Still stock K03s — do not chase big boost.
- stage3 - Hybrid/bigger turbo (K04-15/K04-023 or larger), larger injectors (~380-440cc; rescale KRKTE + TVUB), UPRATED fuel pump, uprated clutch (02J/01A) and often larger MAF + intercooler and cams. Full rework of LDRXN/KFLDRL/boost PID, fueling and timing. Typical K04: ~240-280 hp, ~350-380 Nm. Requires supporting fuel/clutch/cooling AND awareness of the stock-rod limit (~300-320 hp) or reliability suffers.
Safety limits
- WOT lambda target ~0.80-0.82 (AFR ~11.8-12.0 on gasoline); ~0.78 for higher boost/timing. NEVER leaner than ~lambda 0.85 (AFR ~12.5) under load/boost. The stock front O2 is NARROWBAND — verify WOT AFR on an EXTERNAL wideband, not the factory sensor.
- Ignition/knock: keep logged knock retard (KR) minimal — sustained > ~6 deg pull on any cylinder = too aggressive, back timing out. NEVER disable or weaken knock detection (KRFKLN/KFLAMKRL stay protective).
- EGT pre-turbo < ~950 C sustained (930-950 ceiling); NEVER sustained > ~980 C — risks the turbo, exhaust valves and manifold. Enrich and/or pull timing as EGT climbs.
- Boost: stock K03s ~1.0 bar (14-15 psi) sustained max, ~1.1 bar transient spike — beyond that = compressor overspeed/surge and heat-soak. K04 ~1.2-1.3 bar. Keep an overboost fuel-cut as a REAL safety net above target: raise its threshold, never delete it.
- MAF/load ceiling: keep specified load (rlsol) within what the MAF can measure and the turbo can supply without overspeed; MLHFM must cover WOT airflow with MAF voltage below the ~4.9-5.0 V clip (pegged MAF -> fault/limp/lean).
- Torque-monitor lockstep: KFMIRL/KFMIOP and the Level-2 limiters (KFMIZUFIL/KFMIZUOF, miszul) must stay consistent or the ECU applies timing intervention / limp. Do NOT out-request the torque model.
- Injector headroom: stock injectors (~280-317cc) are ~maxed near 200-210 hp; exceeding ~90-95% injector duty = lean risk -> upsize injectors + rescale KRKTE/TVUB BEFORE more power.
- Fuel supply: the stock in-tank lift pump + fuel-pressure regulator cap delivery; a big-turbo/Stage 3 build needs an UPRATED pump (and correct rail pressure) or it goes lean at the top end even with larger injectors.
- MECHANICAL - connecting rods: the 1.8T's stock rods are the known weak point on big-turbo builds; bent rods are common much beyond ~300-320 hp / high sustained torque. Treat this as a hard reliability limit for K04+ unless the rods are upgraded.
- IAT / heat-soak: high intake-air temp sharply raises knock risk — the tune MUST pull timing and add enrichment as IAT rises, and a front-mount intercooler is effectively mandatory for sustained Stage 2+.
- Drivetrain: the 02J/01A manual clutch slips in the low-300s Nm on a hard Stage 3 — upgrade the clutch as torque climbs. Tiptronic/automatic boxes have their own torque limit and need trans-side tuning to hold Stage 3.
- ALWAYS re-run ME7Sum and verify with me7check (and/or WinOLS) before flashing — a bad checksum bricks/limps. Keep a verified (ideally boot-mode-verified) STOCK backup before the first write.
Every car using this platform (27)
Stock power and typical remap figures per car. Stage results assume a healthy engine on good fuel.
| Car | Engine | Engine code | Stock | Stage 1 | Flash access |
|---|---|---|---|---|---|
| Audi A2 8Z 1999–2005 | 1.4 MPI | BBY / AUA | 75 hp | ~82–85 hp — NA, throttle/timing/lambda | OBD flash via KWP2000 on ME7.5; C167 core, ME7 checksum-corr |
| Audi A2 8Z 2002–2005 | 1.6 FSI | BAD | 110 hp | ~115–120 hp — NA direct-injection: tim | OBD flash via KWP2000 on MED7.5; C167/ST10 core, ME7-era che |
| Audi A3 8L 1996-2003 | 1.6 8v NA petrol | AEH/AKL/APF/AVU/BFQ | 100-102 hp | +6-10 hp (light throttle/ignition rema | OBD KWP2000; immo-gated |
| Audi A3 8P 2003-2012 | 1.6 8v NA petrol | BGU/BSE/BSF | 102 hp | +6-10 hp | OBD KWP; immo-gated |
| Audi A3 8L 1996-2003 | 1.8 20v NA petrol | AGN/APG | 125 hp | +8-12 hp remap | OBD KWP2000; M3.8.5 early may need chip/bench; immo-gated |
| Audi A3 8L 1996-2000 | 1.8T 20v turbo petrol | AGU | 150 hp | ~180 hp / 235 Nm (K03, ECU only) | Early M3.8.5 = chip-swap/bench; later ME7.5 = OBD KWP, full |
| Audi A3 8L 1996-2003 | 1.8T 20v turbo petrol | ARX/ARZ/AUM/APP | 150 hp | ~180-190 hp / 250 Nm | OBD KWP2000; immo-gated full flash (10 85) |
| Audi A3 8L facelift 2000-2003 | 1.8T 20v turbo petrol | AUQ | 180 hp | ~205-215 hp / 280 Nm | OBD KWP2000; immo-gated |
| Audi A4 B5 1994–2001 | 1.8L I4 20v turbo petrol | AEB / ANB / APU / AJL / | 150–180 hp hp | ≈200–210 hp / +60–70 Nm — ECU remap (b | OBD KWP2000 SW-download (10 85) — immo-gated; full R/W + imm |
| Audi A4 B6 2000–2004 | 1.8L I4 20v turbo petrol | AVJ / AMB / BFB / BEX | 163–190 hp hp | ≈210–220 hp / +60–70 Nm — remap (boost | OBD KWP2000 SW-download — immo-gated; full R/W + immo-off vi |
| Audi A4 B7 2004–2008 | 1.8L I4 20v turbo petrol | BFB | 163 hp hp | ≈205–215 hp / +60–70 Nm — remap | OBD KWP2000 SW-download — immo-gated; full R/W + immo-off vi |
| Volkswagen Beetle A5 Typ 5C 2012-2019 | 2.5 L5 20v naturally aspirated | CBTA / CBUA | 170 PS / 168 hp hp | ~10-15 hp (NA, map only) | OBD flash; immo-gated; Simos builds need a Simos tool path |
| VW Golf GTI 1.8T Mk4 1997-2004 | 1.8L 20v turbo | AUM / ARZ (US: AWW / AWD | 150 hp | ~180 hp / 250 Nm (remap only) | OBD K-line KWP2000; flash-write immo-gated (10 85), EEPROM r |
| VW Golf GTI 1.8T Mk4 1997-2004 | 1.8L 20v turbo | AGU | 150 hp | ~180 hp / 235 Nm (remap only, raise bo | OBD K-line KWP2000 (Motronic 3.8 uses older KWP/legacy acces |
| VW Golf GTI 1.8T (180 / GTI 'GT') Mk4 2001-2004 | 1.8L 20v turbo | AUQ (US: AWP) | 180 hp | ~205-215 hp / 280 Nm (remap only) | OBD K-line KWP2000; flash immo-gated; boot-mode for locked E |
| Volkswagen Jetta / Bora (GLI trim in US) Mk4 1998-2005 | 1.8L 20v turbo I4 | AGU / AWW / AWD (AUM EU | 150 hp | ~150 -> 180-195 hp / ~260-280 Nm on | OBD KWP2000. Full flash is immo-gated (10 85 refused unless |
| Volkswagen Jetta / Bora GLI Mk4 2002-2005 | 1.8L 20v turbo I4 | AWP (AUQ EU 180) | 180 hp | ~180 -> 205-220 hp via K03s flash ( | OBD KWP2000; full flash immo-gated -> boot-mode/bench for |
| Volkswagen New Beetle 9C 1998-2010 | 1.8T EA113 20v | APH / AWV / AWP | 150 PS (APH/AWV) / 180 PS (AWP Turbo S) hp | 150→~180-190 PS / 180→~205-210 PS (map | OBD flash (ME7.5 via KWP2000); immo + checksum; some locked |
| Volkswagen New Beetle 9C 1998-2010 | 2.0 8v naturally aspirated | AEG / AZG / AVH / BEV / | 115 PS hp | ~5-8 PS only (NA, map/breathing) — not | OBD flash where Bosch ME7.5; Magneti Marelli 4MV needs its o |
| Volkswagen New Beetle 9C 2006-2010 | 2.5 L5 20v naturally aspirated | BPR / BPS / CBTA / CBUA | 150-170 PS hp | ~10-15 hp (NA, map only) | OBD flash; immo-gated; Simos variants need a Simos tool path |
| VW Polo 9N3 GTI 2005-2009 | 1.8T 20v turbo petrol | BJX | 150 (GTI) / 180 (Cup Edition) hp | 175-200 hp / 250-280 Nm — boost, timin | OBD flash via KWP2000 — FULL flash needs 10 85 (immo-gated); |
| Audi S3 8L 1999-2003 | 1.8T 20v turbo petrol | AMK | 210 hp | ~250-260 hp / 320-330 Nm | OBD KWP2000; immo-gated |
| Audi S3 8L facelift 2001-2003 | 1.8T 20v turbo petrol | APY/BAM | 225 hp | ~260-270 hp / 340-350 Nm | OBD KWP2000; immo-gated |
| VW Sharan 7M 1995-2010 | 1.8L I4 20v petrol turbo | AJH (AWC unconfirmed) | 150 hp | ~180hp/280Nm (map only) | OBD (KWP2000 ISO14230); write immo-gated (SKC/login), boot-m |
| Audi TT 8N 1998–2006 | 1.8L I4 20v turbo K03/K03s | AJQ / ARY / AUQ / APP | 180 hp | 200–210 hp — remap only (boost to ~0.9 | OBD KWP2000 read/write; ME7.5 flash is NOT immo-gated — OBD |
| Audi TT 8N 2005–2006 | 1.8L I4 20v turbo K04 | BFV | 240 hp | 260–275 hp — remap on factory K04. | OBD KWP2000 read/write; not immo-gated for flash. |
| Audi TT 8N 1998–2006 | 1.8L I4 20v turbo K04-023 | APX / BAM | 225 hp | 250–265 hp — remap on factory K04 (boo | OBD KWP2000 read/write; ME7.5 not immo-gated for flash. BDM/ |
How confident is this?
SOLID: MCU (Siemens C167) + external 29F400/512KB (or 29F800/1MB) parallel NOR flash + serial-EEPROM immo + K-line KWP2000 flashing + additive multi-region+main checksum architecture with NO crypto signing (ME7Sum/me7check) + the torque-structured control chain and the named maps (KFMIRL, KFMIOP, LDRXN, KFLDIMX, KFLDRL, LAMFA, MLHFM, KRKTE, TVUB, KFZW/KFZW2, torque monitor) — all corroborated by s4wiki, nefmoto and the ME7Sum/ME7RomTool repos. CORRECTED from the draft: the mainstream 1.8T front O2 is NARROWBAND (LSH-25), not wideband, so WOT AFR needs an external wideband; KFLDRL is the FEED-FORWARD/pre-control WGDC map, not a 'post-PID linearization'; the listed engine codes are LONGITUDINAL so part numbers are 8D0/8E0/4B0-series (Bosch 0261 20xxxx), not the transverse 06A prefix; the load system is MAF-primary with a modeled MAP backup, not speed-density; added the stock connecting-rod (~300-320 hp), fuel-supply/pump, and IAT/heat-soak safety limits and softened an over-asserted KRKTE constant. MODERATELY SOLID: exact per-engine stage power figures (vary by box code/fuel/mods/dyno) and boost/EGT ceilings (good engineering rules of thumb, not per-car gospel). THIN / MUST-VERIFY-PE
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