The S1279 Interface is a professional diagnostic adapter module designed for specific PSA Group vehicles (Peugeot and Citroen), especially some newer commercial vehicles based on shared platforms with other manufacturers.

Unlike traditional PSA passenger cars, certain models such as Peugeot Bipper, Peugeot Boxer III, Citroen Nemo, and Citroen Jumper III use different communication protocols due to their cooperation platforms with manufacturers like Fiat and Toyota.

The S1279 module works as a communication bridge between the Lexia 3 / PP2000 diagnostic interface and the vehicle's OBD2 connector, allowing older PSA diagnostic equipment to communicate correctly with these newer vehicles.

By using the S1279 Interface together with Lexia 3, PP2000, or Diagbox software, technicians can perform various diagnostic functions, including fault code reading, live data analysis, actuator tests, and some ECU programming operations.

What Is S1279 Interface?

S1279 Diagnostic Module Overview

The S1279 is an OBD diagnostic adapter specifically developed for Peugeot and Citroen commercial vehicles.

It is installed between the diagnostic interface and the vehicle OBD port to provide protocol conversion and communication compatibility.

Main Purpose of S1279 Module

The primary function of the S1279 Interface is to solve communication problems between traditional PSA diagnostic tools and newer vehicle platforms.

The connection structure is:

				
				
				

					
					

						
						

							
							

								
								

									
									

										
										

											
											

												
												

													
												

												

													
													

														
														

															
															

																
																

																	
Lexia 3 Interface
        ↓
S1279 Module
        ↓
Vehicle OBD2 Socket
																
															
														
													
												
											
										
									
								
								

									

									
								
							
						
					
				

The module acts as an intermediate communication adapter, allowing Lexia 3 and PP2000 systems to access vehicle ECUs that cannot communicate directly.

Why Do You Need S1279 Interface?

Compatibility Problem with New PSA Commercial Vehicles

Early PSA diagnostic systems were mainly designed for Peugeot and Citroen vehicles using standard PSA communication protocols.

However, some newer commercial models were developed through cooperation projects with other manufacturers. These vehicles may use different ECU communication methods, making direct connection with traditional PSA diagnostic interfaces impossible.

The S1279 module provides the required protocol adaptation, enabling successful communication between:

• Lexia 3 diagnostic interface
• PP2000 software
• Diagbox diagnostic platform
• New-generation PSA commercial vehicle ECUs

Supported Vehicles of S1279 Interface

The S1279 diagnostic module is mainly used for PSA commercial vehicles, including:

Peugeot Vehicle Support

Peugeot Bipper

The Peugeot Bipper is a compact commercial van that shares its platform with other European manufacturers.

With the S1279 Interface, technicians can connect Lexia 3 or Diagbox software for vehicle diagnosis and maintenance.

Peugeot Boxer III

The Peugeot Boxer III is a large commercial van requiring special communication support.

The S1279 module helps enable diagnostic communication with Boxer III models, including passenger transport versions.

Peugeot Boxer III Minibus

For Boxer III Minibus models, the S1279 adapter provides better compatibility with PSA diagnostic systems.

Citroen Vehicle Support

Citroen Nemo

The Citroen Nemo is a small commercial vehicle developed through a multi-brand cooperation platform.

Because of its different ECU communication architecture, the S1279 adapter is required for proper diagnosis with Lexia 3.

Citroen Jumper III

The Citroen Jumper III is a large commercial vehicle designed for professional transportation applications.

The S1279 Interface allows technicians to perform diagnostics through PSA factory software.

Citroen Jumper III Minibus

The S1279 module also supports Citroen Jumper III Minibus versions, improving diagnostic compatibility.

S1279 Interface Functions

Diagnostic Functions with Diagbox and Lexia 3

When connected with PSA diagnostic software, the S1279 Interface can provide multiple service functions.

Read and Clear Fault Codes

Technicians can use the S1279 module to:

• Scan vehicle ECU systems
• Read stored diagnostic trouble codes (DTC)
• Clear fault codes after repairs
• Check vehicle system status

Live Data Monitoring

The S1279 adapter supports real-time parameter viewing through compatible diagnostic software.

Users can check:

• Engine sensor values
• Vehicle operating parameters
• ECU communication data
• Graph display information

Actuator Testing

With Diagbox or Lexia software, users can perform actuator tests to verify component operation.

Examples include:

• Checking electronic components
• Testing vehicle systems
• Confirming repair results

ECU Coding and Programming

Depending on the software version, vehicle model, and authorization level, the S1279 Interface may support:

• ECU configuration
• Module matching
• Some programming functions

The available functions depend on the vehicle ECU type and diagnostic software capabilities.

Hardware Structure of S1279 Module

Simple OBD2 Adapter Design

The S1279 Interface features a simple and practical hardware design.

It consists of:

• OBD2 male connector
• OBD2 female connector
• Internal communication adaptation circuit

Plug and Play Installation

The S1279 module does not require:

• Additional drivers
• External power supply
• Special software installation

Users only need to connect it between the PSA diagnostic interface and the vehicle OBD port.

Connection Method

The correct installation sequence is:

				
				
				

					
					

						
						

							
							

								
								

									
									

										
										

											
											

												
												

													
												

												

													
													

														
														

															
															

																
																

																	
Lexia 3 / PP2000 Interface
            ↓
S1279 Female Connector
            ↓
S1279 Male Connector
            ↓
Vehicle OBD2 Port
																
															
														
													
												
											
										
									
								
								

									

									
								
							
						
					
				

How to Use S1279 Interface with PSA Diagnostic Tools

Step-by-Step Operation Guide

Step 1: Prepare Diagnostic Equipment

Prepare:

• Lexia 3 Interface
• PP2000 or Diagbox software
• S1279 Diagnostic Module
• Supported Peugeot or Citroen vehicle

Step 2: Connect S1279 Adapter

Connect the S1279 module between the Lexia 3 interface and the vehicle OBD2 socket.

Make sure all connections are secure before starting diagnosis.

Step 3: Launch PSA Diagnostic Software

Open:

• Diagbox
• Lexia 3
• PP2000

Select the correct vehicle model and start communication.

Step 4: Perform Vehicle Diagnosis

After successful communication, users can perform:

• ECU scanning
• Fault code reading
• Data monitoring
• Component testing
• Available programming functions

Advantages of S1279 Interface

Extend Lexia 3 Compatibility

The biggest advantage of S1279 is that it allows older PSA diagnostic interfaces to work with newer commercial vehicles.

Cost-Effective Diagnostic Solution

Instead of purchasing additional expensive diagnostic equipment, workshops can extend existing Lexia 3 systems by adding the S1279 adapter.

Easy Installation

The plug-and-play design makes installation simple without complicated configuration.

Designed for PSA Commercial Vehicles

The module is specifically developed for Peugeot and Citroen models that require additional communication support.

S1279 Interface Specifications

Frequently Asked Questions About S1279 Interface

What is the S1279 Interface used for?

The S1279 Interface is used to connect PSA diagnostic tools such as Lexia 3 and PP2000 with certain Peugeot and Citroen commercial vehicles that cannot communicate directly due to different ECU protocols.

Does S1279 work without Lexia 3?

No. The S1279 module is an adapter and requires compatible PSA diagnostic equipment such as Lexia 3, PP2000, or Diagbox.

Which vehicles support S1279?

The main supported vehicles include:

• Peugeot Bipper
• Peugeot Boxer III
• Peugeot Boxer III Minibus
• Citroen Nemo
• Citroen Jumper III
• Citroen Jumper III Minibus

Does S1279 require software installation?

No. The S1279 module is hardware-based and does not require additional drivers or software.

Can S1279 program ECU modules?

The S1279 Interface may support some ECU coding or programming functions when used with compatible Diagbox software. Available functions depend on vehicle model and software version.

Conclusion

The S1279 Interface is an essential diagnostic adapter for Peugeot and Citroen commercial vehicle technicians using Lexia 3, PP2000, or Diagbox systems.

It solves communication compatibility issues found on vehicles such as Peugeot Bipper, Boxer III, Citroen Nemo, and Jumper III, especially models developed through shared platforms with other manufacturers.

With its simple plug-and-play design and reliable protocol adaptation capability, the S1279 module provides an affordable way to extend PSA diagnostic system coverage and maintain compatibility with newer commercial vehicles.