Scope and identification
Audi’s 2009 2.0 TDI clean-diesel programme and its 2014 third-generation 2.0 TDI programme document two different Bosch EDC17 common-rail systems. Their injector, pressure-control, EGR and exhaust systems are vehicle-specific. The training documents name the family EDC17 but do not identify a more precise EDC17 suffix for these examples. Verify the installed ECU, engine code, software and emissions equipment before applying a diagnostic value or calibration definition.
Injection and fuel pressure
The 2009 clean-diesel example has piezo injectors and a maximum stated injection pressure of 1,800 bar. Its rail-pressure sender G247 measures pressure; metering valve N290 controls pump supply and regulator N276 controls the rail return. Audi describes control by either valve or both according to operating conditions: N276 is used during starting and fuel heating, while N290 regulates fuel delivery at larger injection quantities; both are used at idle and small quantities. The publication describes both N276 and N290 as open when not energised in this installation. The described piezo injector return uses a retention valve at about 10 bar. Audi SSP 920193, printed pages 27–29 and 37–41.
The 2014 US CRUA example is rated at 110 kW and 320 Nm in Audi’s training document. It uses solenoid-operated injectors, with a stated maximum injection pressure of 2,000 bar. Its diagram gives injector-return pressure of 0.4–1.0 bar. These figures describe different illustrated systems, not recommended test values or targets for EDC17 generally. Audi eSSP 920143, printed pages 9 and 39–42.
In the 2014 example, cold-fuel heating can also involve delivering more fuel to the high-pressure pump and routing warmed fuel through N276 towards the filter supply. This is a described operating mode, so pump delivery and injected quantity need not be identical. eSSP 920143, printed page 43.
Air and combustion feedback
The 2009 example has high- and low-pressure EGR paths and variable turbocharger geometry. Cylinder-pressure sensors G620–G623 are integrated into the glow plugs; Audi describes using their combustion feedback for injection correction and balancing. If one sensor fails, the described system substitutes a value from the others. This is equipment in that documented installation, not a feature of every EDC17. SSP 920193, printed pages 48–49.
In the 2014 example, low-pressure EGR is taken downstream of the particulate filter and routed through the turbocharger. The system overview identifies airflow sensor G70, charge-pressure sensor G31 and charge-actuator position sensor G581: these represent different parts of the air system, not interchangeable readings. eSSP 920143, printed pages 45 and 49–52.
The 2014 programme describes a charge-air cooler integrated into the intake manifold. The ECU uses post-cooler temperature G811 to control cooling pump V188 and compares temperatures with G42. Audi describes fixed substitute values for these temperature-sensor failures; V188 failure is recorded and excessive intake temperature can lead to reduced output. It also describes variable camshaft timing on versions meeting the specified EU6 or BIN5 Tier 2 standards, rather than as equipment on every EDC17 engine. eSSP 920143, printed pages 19–21 and 53–54.
Aftertreatment and diagnosis
For the 2009 system Audi describes two particulate soot-load models, one using the driving and temperature context and another using filter-flow resistance. Its separate NOx reduction catalyst has distinct NOx and sulphur regeneration modes; the ECU coordinates the operating conditions. Audi’s 2009 training example illustrates escalating restrictions at soot loads of 40 g and 45 g, including service-only regeneration and a point beyond which it says service regeneration is not possible. These are historical, system-specific examples, not universal service thresholds; use current vehicle-specific guidance. A failed signal or an unsuitable operating state can affect regeneration without establishing that the filter itself has failed. SSP 920193, printed pages 64–65 and 70–75.
For that same 2009 example, Audi says loss of G31 stops boost-pressure regulation and active particulate-filter regeneration, while loss of G581 leads the ECU to use charge pressure and engine speed as substitutes for vane-position calculation. Follow the applicable current repair information and fault-tracing procedure; these fallback behaviours should not be assumed for other software. SSP 920193, printed pages 52–53.
Audi’s 2014 US example uses a reducing-agent injector and an SCR-coated particulate filter. It also describes an ammonia-blocking catalyst and a return-flow pump that draws reducing agent back after shutdown. In the A3 system described, Audi gives an approximate 6.5 bar (± 2 bar) delivery equilibrium and describes estimating pressure from pump electrical behaviour rather than using a separate pressure sensor; this figure is not a general SCR test limit. Its SCR arrangement should be identified on the actual vehicle before comparing it with another aftertreatment system. eSSP 920143, printed pages 60–66.
For the general request-to-fuel relationship, see EDC17 torque fuel and tuning basics.
Sources
- Audi Self-Study Program 920193: 2.0 Liter TDI Common Rail Engine with Clean Diesel System, Audi of America Service Training, August 2009, printed pages 4, 27–29, 37–41, 48–53, 64–67 and 70–75; independent mirror. Historical design information, not a repair manual.
- Audi eSelf Study Program 920143: The Audi 2.0L Third Generation TDI Engine, Audi of America Service Training, revision 1, May 2014, printed pages 9, 19–21, 39–43, 45, 49–54 and 60–66; hosted by NHTSA. Historical design information, not a repair manual.