Citroën ECU – HDi, SID, Bosch & PSA Engine Control Units

Citroën engine control units – ECU identification by PSA and manufacturer part number

A Citroën engine control unit (ECU), also known as an ECM or engine computer, manages engine operation and communicates with other electronic systems in the vehicle. Depending on the engine and ECU generation, it may control fuel injection, ignition in petrol engines, fuel pressure, turbocharger operation, electronic throttle control and selected emissions-related systems.

When replacing a Citroën ECU, however, the most important step is identifying the exact electronic module fitted to the vehicle. Citroën has used numerous engine-management systems from Bosch, Siemens, Magneti Marelli, Delphi and other suppliers. Similar-looking control units can contain different hardware, software, calibration and vehicle-specific security data.

Citroën and PSA ECU numbers beginning with 96 and 98

Many Citroën engine control units carry characteristic PSA OEM references beginning with 96... or 98.... Examples in the Auto24Parts catalogue include:

• 9664339980,
• 9664934380,
• 9630901380,
• 9801572080,
• 9813283980,
• 9653492680,
• 9666325380,
• 9666934280,
• 9802218680.

The complete number should always be compared. A shared 96 or 98 prefix does not indicate that two ECUs are interchangeable.

Why does a Citroën ECU have several numbers?

A Citroën ECU label can contain several identifiers from both PSA and the electronics manufacturer. Depending on the module, these can include:

• Citroën / PSA OEM part number,
• Bosch, Siemens, Magneti Marelli or other manufacturer number,
• ECU family such as SID 802, SID 804 or IAW6LP205,
• software reference marked SW,
• hardware reference marked HW,
• additional calibration or production codes.

For precise identification, several references should be checked together rather than relying on the vehicle model or one shortened number.

Citroën IAW6LP205 – 9664339980 / 9664934380

One current petrol engine control unit is the Citroën ECU IAW6LP205 / 9664339980 / 9664934380.

This module combines the IAW6LP205 engine-management designation with two PSA references: 9664339980 and 9664934380.

The complete IAW designation and PSA numbers should be compared with the original ECU. A module that has a similar Magneti Marelli housing but carries a different IAW or PSA reference should not automatically be considered compatible.

Citroën C2 1.4 HDi – SID 804 / 5WS40111CT

A characteristic diesel example is the Citroën C2 1.4 HDi Siemens SID 804 ECU 5WS40111CT.

The complete identification includes:

• SID 804,
• 5WS40111C-T / 5WS40111CT,
• SW9653447380,
• HW9648624280.

This demonstrates why the ECU family alone is not sufficient. There are many SID control units, so the complete Siemens, software and hardware references should also be checked.

Citroën C3 1.4 HDi – SID 802 / 5WS40021FT

Another Siemens diesel module is the Citroën C3 1.4 HDi SID 802 ECU 5WS40021FT.

This unit carries:

• SID 802,
• 5WS40021F-T / 5WS40021FT,
• SW9647202380,
• HW9643455080.

Although both SID 802 and SID 804 are Siemens diesel engine-management systems used in PSA applications, they should not be treated as the same ECU family or as interchangeable modules.

Citroën Bosch 0261S07689 / 9801572080

The current range also includes the Citroën Bosch ECU 0261S07689 / 9801572080.

This module combines Bosch reference 0261S07689 with PSA OEM number 9801572080. Both references should be checked against the original control unit before ordering.

The current product page offers different preparation possibilities, so the required version should be selected according to the ECU and vehicle application.

Citroën / Peugeot Bosch 0261S04616 / 9666325380

Some PSA engine control units are listed for both Citroën and Peugeot applications. One example is the Citroën / Peugeot Bosch ECU 0261S04616 / 9666325380.

A shared Citroën / Peugeot application does not mean that every ECU can be moved freely between the two brands. The exact PSA number, Bosch reference, software, hardware and vehicle configuration should still be verified.

Citroën / Peugeot Bosch 0261S05626 / 9666934280

Another current shared PSA module is the Citroën / Peugeot ECU Bosch 0261S05626 / 9666934280.

The Bosch number 0261S05626 and PSA reference 9666934280 provide two useful search routes to the same electronic module.

The current product is available in locked and ready-for-programming preparation variants. The exact procedure required after installation depends on the vehicle and how the ECU has been prepared.

Citroën / Peugeot Bosch 0281012466 / 9661135380

The diesel range also includes the Citroën / Peugeot Bosch ECU 0281012466 / 9661135380.

The Bosch reference may also be written as 0 281 012 466. Searching both the compact and formatted versions can be useful when comparing workshop records or the label on the original ECU.

Citroën / Peugeot 0281018463 / 9802218680

Another Bosch control unit is the Citroën / Peugeot ECU 0281018463 / 9802218680.

This example belongs to a newer PSA 98... OEM numbering range. As with other modules, both the Bosch and PSA numbers should be compared before ordering.

Citroën SID 802, SID 804 and other SID engine control units

Siemens SID modules are particularly relevant to Citroën HDi applications. Different generations can carry designations such as SID 802, SID 804 and other SID-family references.

The family name is useful for narrowing the search, but it is not enough on its own. For example, the current catalogue contains:

• SID 804 / 5WS40111CT / SW9653447380 / HW9648624280,
• SID 802 / 5WS40021FT / SW9647202380 / HW9643455080.

The complete 5WS number and the SW / HW references are important because visually similar SID modules can use different hardware and software.

SW and HW numbers on Citroën ECUs

Citroën and PSA ECU labels frequently contain additional SW (software) and HW (hardware) references. These numbers can provide important information when distinguishing different electronic versions.

For example:

• SW9653447380 / HW9648624280 on one SID 804 module,
• SW9647202380 / HW9643455080 on one SID 802 module.

When two ECUs have the same general family but different software or hardware identification, compatibility should be verified before replacement.

Magneti Marelli Citroën engine control units

Citroën petrol applications also use Magneti Marelli engine-management systems. The current category includes modules from the IAW family, including IAW6LP205, as well as other Magneti Marelli systems.

You can also browse the Magneti Marelli automotive electronics section.

The IAW family designation and PSA part number should be considered together when identifying the replacement ECU.

Bosch engine control units for Citroën

Bosch modules form another large group within Citroën and Peugeot engine electronics. Current examples use both 0261S... petrol ECU references and 0281... diesel ECU numbering.

You can browse other Bosch automotive control units available at Auto24Parts.

The Bosch number should always be checked together with the corresponding PSA OEM reference because the same Bosch ECU family can contain many different hardware and software versions.

Citroën and Peugeot – shared PSA engine control units

Citroën and Peugeot share numerous engines, platforms and electronic systems. As a result, some engine control units in the Auto24Parts catalogue are listed for both brands.

Current examples include:

• 0261S04616 / 9666325380,
• 0261S05626 / 9666934280,
• 0281012466 / 9661135380,
• 0281018463 / 9802218680.

This does not mean that every Citroën and Peugeot ECU is universally interchangeable. The exact OEM number, manufacturer reference, engine version, hardware, software and vehicle configuration still need to be checked.

Related modules can be found in the Peugeot engine control unit category.

Citroën ECU, BSI and immobiliser synchronisation

In many Citroën vehicles, engine-start authorisation involves communication between the engine ECU and other vehicle electronics, including the BSI and immobiliser system.

A standard used ECU can retain security information from its previous vehicle. Installing another module therefore does not necessarily mean that the engine will start immediately.

Depending on the vehicle, ECU family and preparation method, programming, security synchronisation, cloning or another adaptation procedure may be required.

Used / locked Citroën ECU

A standard used / locked Citroën engine control unit normally retains the data of its previous vehicle. Such a module is mainly intended for workshops and automotive electronics specialists equipped to prepare and programme replacement ECUs.

The exact preparation procedure depends on the ECU family, vehicle security system and intended installation method.

Citroën ECU ready for programming

Many Citroën products in the Auto24Parts catalogue are available in locked and ready-for-programming variants. Selected products may offer other preparation methods.

The available option depends on the specific ECU and vehicle. Programming, configuration or immobiliser-related adaptation may still be required after installation.

See our ECU preparation options for more information.

VIRGIN Citroën ECU

For selected Citroën engine control units, the module can be reset or prepared in a VIRGIN state for subsequent adaptation to another vehicle.

The exact installation procedure depends on the ECU and vehicle generation. A VIRGIN ECU should therefore not automatically be considered Plug & Play. Programming or synchronisation with the vehicle electronics may still be required.

Citroën ECU cloning

For selected compatible modules, Citroën ECU cloning may be another preparation solution. If the required data can be correctly read from the original control unit, relevant information may be transferred to a compatible replacement ECU.

Depending on the control-unit design, this may include EEPROM or FLASH data, software, configuration and immobiliser-related information.

The possibility of cloning depends on the ECU family and condition of the original module. If the required information cannot be recovered, another preparation method may be necessary.

Why the complete Citroën ECU label matters

A replacement Citroën ECU should not be selected only from the housing, connector layout or vehicle model. The preferred identification sequence is:

• complete Citroën / PSA OEM number,
• Bosch, Siemens, Magneti Marelli or other manufacturer reference,
• ECU family such as SID 802, SID 804 or IAW6LP205,
• SW and HW references where available,
• vehicle model and production year,
• engine capacity and engine version,
• transmission and relevant vehicle configuration where required.

Common symptoms that may indicate a Citroën ECU problem

A defective engine control unit can cause different symptoms, but similar problems can also result from sensors, wiring, fuel-system components, actuators, power-supply faults or communication problems.

• engine does not start,
• no diagnostic communication with the ECU,
• engine stalls or is difficult to restart,
• limp mode or reduced engine power,
• injector or ignition-control faults,
• incorrect throttle response,
• fuel-pressure or turbocharger-control problems,
• communication faults between vehicle modules,
• diagnostic trouble codes that repeatedly return,
• internal ECU memory or electronic faults.

Before replacing the module, check battery voltage, ECU power supply, ground connections, fuses, relays, connectors and wiring. A diagnostic trouble code alone does not prove that the ECU itself is defective.

Citroën engine control units by exact part number

Searching by the complete PSA and electronics manufacturer references is one of the most effective ways to locate the correct Citroën ECU:

• IAW6LP205 / 9664339980 / 9664934380 – Citroën Magneti Marelli ECU
• 0261S07689 / 9801572080 – Citroën Bosch ECU
• SID 804 / 5WS40111CT / SW9653447380 / HW9648624280 – Citroën C2 1.4 HDi
• SID 802 / 5WS40021FT / SW9647202380 / HW9643455080 – Citroën C3 1.4 HDi
• 0261S04616 / 9666325380 – Citroën / Peugeot Bosch ECU
• 0261S05626 / 9666934280 – Citroën / Peugeot Bosch ECU
• 0281012466 / 9661135380 – Citroën / Peugeot Bosch ECU
• 0281018463 / 9802218680 – Citroën / Peugeot ECU

How to check Citroën ECU compatibility before ordering

Take a clear photo of the complete original control-unit label. The Citroën / PSA OEM number, Bosch, Siemens, Magneti Marelli or other manufacturer reference, ECU-family designation and SW / HW numbers should all be readable.

If you need help identifying the correct replacement module, contact Auto24Parts and send the photo together with the Citroën model, model year, engine capacity, power output and engine version.

For other vehicle makes, browse the complete engine control unit catalogue. Other Citroën electronic components can also be found in the Citroën ABS pump category.

Before ordering, you can also review our How to Buy guide, Shipping & Delivery information and Returns, Warranty & Complaints conditions.

FAQ – Citroën ECU and Engine Control Units