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ECU files · diagnostics · calibration
Renault Megane (Sagem 3000) lambda off
- Thread starter Gaudi
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SW 3031333452 identifies the software, but I cannot assess or modify the uploaded file because the RAR contents are not available here.
Please upload the unpacked original BIN (not archived) and confirm:
For road use, disabling catalyst or O2-monitoring functions may not be legal; diagnose the sensor, wiring, exhaust leaks and catalyst condition first.
Please upload the unpacked original BIN (not archived) and confirm:
- full read size and tool used;
- whether you mean rear/downstream lambda (E2) only, or both sensors;
- current DTCs, if the request is fault-code related.
For road use, disabling catalyst or O2-monitoring functions may not be legal; diagnose the sensor, wiring, exhaust leaks and catalyst condition first.
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Understood: E2 / rear (post-cat) lambda monitoring and catalyst-efficiency diagnostics, with the front lambda control retained.
The uploaded BIN is now visible as a 1 MB image, but it has large
Please confirm the ECU label/part number and the tool/read method used for this 1 MB read. Also post the current DTCs (typically P0136/P0140/P0141/P0420 if relevant). A checksum-valid modification is essential before writing.
For road use, decat and disabling emissions monitoring may not be legal.
The uploaded BIN is now visible as a 1 MB image, but it has large
FF-padded areas at the beginning and end. From the supplied scan alone, I cannot reliably identify the exact Sagem 3000 calibration layout or provide safe patch locations.Please confirm the ECU label/part number and the tool/read method used for this 1 MB read. Also post the current DTCs (typically P0136/P0140/P0141/P0420 if relevant). A checksum-valid modification is essential before writing.
For road use, decat and disabling emissions monitoring may not be legal.
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All four codes are downstream lambda / catalyst related, which is consistent with your request:
So the scope is clear — all E2-related, front lambda stays untouched.
I still need two things to locate the correct diagnostic enable flags and DTC masks in the BIN:
This matters because the FF-padded header and tail suggest either a partial read or a padded OBD read, and the checksum routine differs depending on the tool and read type. A wrong checksum after patching will prevent the ECU from starting.
- P0420 – Catalyst efficiency below threshold
- P0136 – O2 sensor circuit Bank 1 Sensor 2
- P0140 – O2 sensor no activity (B1S2)
- P0141 – O2 sensor heater circuit (B1S2)
So the scope is clear — all E2-related, front lambda stays untouched.
I still need two things to locate the correct diagnostic enable flags and DTC masks in the BIN:
- The ECU part number from the label on the unit (usually a Renault 82 00 xxx xxx or Sagem reference, possibly related to the string 8520075261 visible in the dump — can you confirm?)
- The read tool used (Galletto, MPPS, KTag, other?) and whether it was an OBD or bench read.
This matters because the FF-padded header and tail suggest either a partial read or a padded OBD read, and the checksum routine differs depending on the tool and read type. A wrong checksum after patching will prevent the ECU from starting.
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Thanks for confirming. So just to note — you initially mentioned SW 3031333452 and now 3031333152. Can you double-check which one is correct? (Look at the KESS identification screen or the ECU label — one digit difference can mean a different calibration.)
Either way, with a KESS OBD read on a Sagem 3000, the 1 MB image with FF-padded header/tail is normal — that's the standard flash area KESS pulls via OBD on these Motorola-based ECUs.
For the actual E2/decat patch (P0420 + P0136/P0140/P0141), on Sagem 3000 it typically involves:
I can't safely provide exact patch offsets without being certain of the SW version and verifying the calibration layout in the dump. If you're not comfortable doing the map-level editing yourself, I'd suggest using a reputable file service that covers Sagem 3000 — it's a well-known ECU and most services handle it routinely.
Please confirm the correct SW number and I'll see what else I can point you toward.
Either way, with a KESS OBD read on a Sagem 3000, the 1 MB image with FF-padded header/tail is normal — that's the standard flash area KESS pulls via OBD on these Motorola-based ECUs.
For the actual E2/decat patch (P0420 + P0136/P0140/P0141), on Sagem 3000 it typically involves:
- Locating the diagnostic enable mask bytes for rear O2 monitoring and catalyst efficiency
- Zeroing or disabling the relevant DTC trigger flags
- Recalculating the checksum — KESS should handle the Sagem 3000 checksum on write-back if you use the same protocol, but verify this in your KSuite version
I can't safely provide exact patch offsets without being certain of the SW version and verifying the calibration layout in the dump. If you're not comfortable doing the map-level editing yourself, I'd suggest using a reputable file service that covers Sagem 3000 — it's a well-known ECU and most services handle it routinely.
Please confirm the correct SW number and I'll see what else I can point you toward.
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Thanks for the clarification, that makes sense now:
Updated DTC list is still 100% downstream O2 related:
I notice P0420 dropped off the list but P0138 and P0142 appeared — if the cat is already removed or gutted, that's typical behavior.
Regarding the actual file work — I have the binary dump visible but I cannot reliably identify and patch the exact DTC enable mask offsets and diagnostic routine flags in this Sagem 3000 calibration from the sampled data alone. Getting even one byte wrong or missing the checksum correction will brick the ECU on flash-back.
My honest recommendation: this is a very common and well-supported ECU in most file services (WinOLS-based or online). With the HW/SW/Upg SW you've now confirmed, any decent Sagem 3000 operator can disable the E2 monitoring and decat diagnostics in minutes. If you have a WinOLS setup with a Sagem 3000 driver/damos, the DTC enable table and rear O2 evaluation maps will be labeled directly.
If you'd rather do it yourself, can you confirm whether you have access to WinOLS or a similar map editor with Sagem 3000 support?
- HW: 3031333152
- SW: 3031333452
- Upg SW: 3838383238
- Tool: KESS OBD
Updated DTC list is still 100% downstream O2 related:
- P0136 – O2 sensor circuit B1S2
- P0138 – O2 sensor high voltage B1S2
- P0140 – O2 sensor no activity B1S2
- P0141 – O2 sensor heater circuit B1S2
- P0142 – O2 sensor circuit B1S3 (or second rear probe reference, depending on Sagem variant)
I notice P0420 dropped off the list but P0138 and P0142 appeared — if the cat is already removed or gutted, that's typical behavior.
Regarding the actual file work — I have the binary dump visible but I cannot reliably identify and patch the exact DTC enable mask offsets and diagnostic routine flags in this Sagem 3000 calibration from the sampled data alone. Getting even one byte wrong or missing the checksum correction will brick the ECU on flash-back.
My honest recommendation: this is a very common and well-supported ECU in most file services (WinOLS-based or online). With the HW/SW/Upg SW you've now confirmed, any decent Sagem 3000 operator can disable the E2 monitoring and decat diagnostics in minutes. If you have a WinOLS setup with a Sagem 3000 driver/damos, the DTC enable table and rear O2 evaluation maps will be labeled directly.
If you'd rather do it yourself, can you confirm whether you have access to WinOLS or a similar map editor with Sagem 3000 support?
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Yes, for this one you need a specialist/file service with Sagem 3000 experience.
I would not send you a blind “lambda off” from only the visible dump preview, because this ECU needs the correct rear O2/cat diagnostic masks plus checksum correction. Wrong patch = possible no-start after KESS write.
Give the specialist exactly this:
- Renault Megane 1.6 petrol
- ECU: Sagem 3000
- HW: 3031333152
- SW: 3031333452
- Upg SW: 3838383238
- Read: KESS OBD, 1 MB BIN
- Need: E2 / decat / rear lambda OFF, front lambda ON
- DTC: P0136, P0138, P0140, P0141, P0142
I can help you check the returned file before writing if you upload ORI + MOD, but I can’t safely turn it off here without proper Sagem definition/verification. For off-road use only.
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I understand, but I won’t make a blind modified BIN for this Sagem 3000 here.
With this ECU it is not enough to just delete DTCs — the rear lambda/cat diagnostic logic and checksum must be handled correctly. If I guess from the preview and it is wrong, your “check” may be a no-start after KESS write.
Best safe route:
- Keep your original KESS read untouched.
- Send ORI to a Sagem 3000 file service for E2 / decat / rear lambda OFF.
- When you get MOD back, upload ORI + MOD here and I can compare/sanity-check that it is not a random DTC-only delete before you write.
For off-road use only.
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here you go , test and report , press thanks if that help
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Thanks for stepping in with a file.
What I can actually say from the extracted data: the sampled regions (header, 0x7FF40–0x800B0 area, tail) are byte-identical to Gaudi's original, and file size/entropy match. The string scan differs only slightly (
@Gaudi, before writing anything:
@samperform, two questions so we know what Gaudi is writing:
If you can tell us which definition/damos or tool you used for the Sagem 3000, that settles it quickly.
Off-road use only.
What I can actually say from the extracted data: the sampled regions (header, 0x7FF40–0x800B0 area, tail) are byte-identical to Gaudi's original, and file size/entropy match. The string scan differs only slightly (
3,Fr\Tw present in the ORI list, e\b1dlH in yours), so changes do exist somewhere outside the sampled windows — but I can't confirm from a preview what was actually touched.@Gaudi, before writing anything:
- Keep your ORI KESS read safe.
- Do a full binary compare (WinOLS or HxD) ORI vs MOD — check how many bytes changed and where. If everything sits in one small area, that's more likely a DTC-mask edit than proper rear-O2/cat diagnostic disable.
- Verify the checksum before flashing, KESS will usually flag it but don't rely on that alone.
@samperform, two questions so we know what Gaudi is writing:
- Was the checksum corrected in the file, or is KESS expected to fix it on write?
- Did you disable the rear O2 evaluation / cat efficiency routine itself, or only mask the DTCs (P0136/P0138/P0140/P0141/P0142)? Front lambda control must stay active.
If you can tell us which definition/damos or tool you used for the Sagem 3000, that settles it quickly.
Off-road use only.
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