Complete Guide Renault 19 Mk2 Engine Control Unit ECU 1992-1999 | S101262101 D / HOM7700742850 / 7700744413
The Renault 19 Mk2 ECU: Repair vs. Replace Analysis
For owners of the classic Renault 19 Mk2, a faulty Engine Control Unit (ECU) is a common, yet critical, issue. The decision between repairing the existing unit and replacing it hinges on a meticulous cost-benefit analysis.
1. The Financial and Mechanical Threshold
| Scenario | Financial Threshold (General) | Mechanical/Risk Threshold |
| Repair | Cost is less than 50% of a replacement unit. | Minor component failure (e.g., failed capacitor, single driver chip). Low Risk if done by a specialist with a warranty. |
| Replacement | Cost of repair approaches or exceeds 50% of a replacement. | Major internal damage (e.g., processor failure, water damage, or multiple damaged circuits). Higher long-term reliability with a new/refurbished unit. |
Key ECU Part Numbers Covered:
2. Does a Replacement ECU Need Programming? (The Immobilizer Factor)
For the Renault 19 Mk2, particularly those produced after 1995/1996, the ECU is linked to the vehicle's immobilizer system.
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New/Used Replacement ECU: YES, PROGRAMMING IS LIKELY REQUIRED.
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The replacement ECU must be coded to the specific vehicle's immobilizer (UCH or corresponding system) and keys. Failure to do so will result in a no-start condition.
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This procedure typically requires specialist diagnostic tools (like Renault's Clip tool) or sending the unit to a specialized programmer to clone the data from your old ECU onto the new one.
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Plug-and-Play Option:
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A 'Decoded' or 'Immo-Off' ECU is available from some suppliers. These units bypass the immobilizer security, allowing for true plug-and-play installation, but this may compromise vehicle security and is often illegal in certain jurisdictions. Always check local laws.
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The best solution is a Cloned ECU, where your old unit's data is transferred—effectively making the new unit a direct, plug-and-play copy.
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FAQ: Renault 19 Mk2 ECU
| Question | Answer |
| What are the symptoms of a failing ECU? | Engine misfires, intermittent starting, sudden loss of power, engine stalling, and persistent check engine lights that do not clear after sensor replacement. |
| Are the S101262101 D, HOM7700742850, and 7700744413 interchangeable? | Not necessarily. These numbers indicate different hardware and/or software versions for specific engine configurations (e.g., different engine codes or emission standards). Always match the original part number exactly. |
| Can I replace the ECU myself? | The physical replacement is straightforward (usually in the passenger footwell or near the engine bay), but the required programming/coding often necessitates a professional mechanic or specialist. |
Compatibility Table (Example Only - Always Match Full Part Number)
| Engine Type (Example) | Year Range (Mk2) | Common ECU Part Number | Notes |
| 1.4L E7J (Mono-Injection) | 1992-1996 | S101262101 D | Often Siemens/Bendix. Early models may be simpler to program. |
| 1.8L F3P (Multi-Point) | 1993-1999 | HOM7700742850 | Typically higher-spec engines. Programming almost always needed. |
| 1.9L Diesel (Early) | 1992-1995 | 7700744413 | May be a control unit for the electronic injection pump (non-ECU for ignition on diesel). |
TLDR (Too Long; Didn't Read)
Your Renault 19 Mk2 ECU (S101262101 D, HOM7700742850, 7700744413) failure requires a careful repair vs. replacement cost check. If the repair is less than 50% of replacement cost, repair is viable. A replacement ECU will almost certainly need programming (cloning or immobilizer coding) to function in your car. Match the full part number exactly for compatibility.
Your Trusted European ECU Source
At Automan Spare Parts, we understand the challenge of sourcing reliable ECUs for classic European models. We are proud to be a No. 1 European supplier with a huge range of Genuine OEM ECUs, including those for the Renault 19 Mk2. We offer the cheapest rates and provide fast shipping globally. Whether you need a direct replacement or a cloned plug-and-play unit, trust us for quality and speed.
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