Scope and identification
Diagnostic readings describe a particular ECU, operating condition and tool. Start by recording the vehicle, engine, ECU hardware and software, injection system, equipment and fault codes. A request, limit, calculated value and physical sensor reading are different things; confirm the units, sign and reference of every channel before comparing them.
Fuel, air, torque and timing data
The Snap-on Volkswagen/Audi manual, printed pages 136–139 describes example diesel parameters for indicated and desired injection quantity and for driver, torque, smoke, cruise, traction-control and automatic-transmission influences. It also describes desired and actual air mass, boost and timing, and cylinder correction values. These are generic tool descriptions, not proof that every listed channel exists on an EDC16 or that a reported quantity is directly measured.
When available, compare request, active limit and actual feedback under the same conditions. Confirm whether pressure is absolute or gauge, and distinguish air mass from boost pressure. Cylinder-balance corrections show a control response and do not on their own identify a faulty injector. Record fault status and freeze-frame information before clearing codes, and check whether a plausible reading could be a substitute value.
AutoTuner’s Renault-group logging announcement includes EDC16CP42 among supported controllers. Its group-wide list includes examples such as air-mass and boost setpoints, fuel pressure and setpoint, injection quantity and timing, torque limits and temperatures. That list also covers other diesel and petrol ECUs; it does not establish that each channel is available on an individual CP42 vehicle.
Citroën 1.4/1.6 HDi: Lexia and Proxia bulletin
Citroën INFO’DIAG 409, dated 17 January 2008, concerns specified Citroën 1.4 and 1.6 HDi applications with EDC16C3 or EDC16C34. It discusses unusual displayed air-flow-meter temperature on a cold 1.6 HDi, a possible “regeneration impossible” message and replacement-ECU configuration. This is a vehicle- and software-specific bulletin, not an EDC16-wide test or a general instruction to regenerate a filter. Citroën INFO’DIAG 409, pages 1–3.
For the cold temperature display discussed in the bulletin, Citroën directs the technician to follow the fault tree and check the wiring, connections and sensor if a flow-meter fault is reported; in the absence of that fault it says not to replace the sensor on that reading alone. It also says the availability of the tool’s forced-regeneration function can depend on ECU software. Check the latest vehicle-specific diagnostic guidance and conditions instead of assuming that a scan-tool message establishes the cause.
Replacement ECU configuration in the same bulletin
For the replacement units covered by this 2008 bulletin, Citroën describes new ECUs delivered without vehicle configuration. Its tables vary with vehicle, engine, software and equipment, including cooling, transmission, cruise control, speed limiter, ABS/ESP and injection-system details. Citroën treats ABS and ESP as separate configuration items. Its procedure calls for a power-latch interval of at least one minute after each configuration; verify the current instructions for the exact vehicle and tool before performing any coding. INFO’DIAG 409, pages 4–18.
The bulletin distinguishes CP1.H and CP3.2 high-pressure pumps in its covered applications and warns that an incorrect pump configuration can cause non-starting or difficult starting and stalling. It describes different normal states for the two fuel-flow regulators. Do not select a pump setting from engine size or ECU name alone; identify the fitted hardware and use the correct current manufacturer procedure. INFO’DIAG 409, pages 18–19.
Scan-tool access and testing
Snap-on notes that its VW/Audi combined codes-and-data screen can contain only a selection of measuring groups and may refresh more slowly. Its measuring-value and basic-settings functions are different operations, and availability varies with vehicle and tool. Missing data or a communication failure does not by itself prove an ECU defect; check identification, power, connections and the correct diagnostic path. Snap-on, printed pages 42–43 and 154–156.
For documented unit-injector, common-rail and multi-ECU examples, see EDC16 injection systems and vehicle examples. Verify programming read scope and coding preservation for the exact tool and ECU before relying on a file as a complete backup.
Sources
- Citroën INFO’DIAG 409: Diagnosis of Bosch EDC16C3 / EDC16C34, 17 January 2008, pages 1–19; independent reproduction; historical vehicle-specific service information.
- Snap-on Volkswagen/Audi Vehicle Communication Software Manual, EAZ0031B01E Rev. A, August 2013, printed pages 42–43, 136–139 and 154–156; independent PDF mirror.
- AutoTuner: Renault-group specific datalogging; group-level, tool-specific coverage; accessed 10 November 2026.