Notes on actuations - AH07.00-P-3000-03WA
ME-SFI fuel injection and ignition system with hand-held tester or with STAR DIAGNOSIS
ACTUATIONS DESCRIPTION
| Actuations in HHT (HHT-WIN) | Function | |
|---|---|---|
| Camshaft | ON | Engine does not idle smoothly. |
| Air pump | ON | O2 sensor voltage moves to < 40 mV in max. 60 s. |
| Injectors | OFF ON |
When individual injectors switched off, engine speed drops for a short time. Engine running deteriorates. When injectors switched on, engine speed is again okay. |
| Throttle valve | OPEN CLOSE |
Throttle valve angle becomes greater and engine speed rises. Throttle valve angle becomes less and engine speed drops. |
| Fuel pump | OFF | OFF: fuel system becomes pressureless and engine is switched off. |
| Purge system | ON | Purge control valve ON: purge control valve is heard or felt to operate. |
| Activated charcoal canister shutoff valve (only USA) | ON | Only when engine switched off for testing purge control system for leaks. |
| Exhaust gas recirculation | ON | Engine does not run smoothly or stops. |
| Mixture adaptation | RICH/LEAN | LEAN: idle speed deteriorates. |
| Smooth engine running shutoff threshold | POSITIVE/NEGATIVE | Reduce shutoff threshold; this makes it possible to more rapidly detect a possible fault. |
| Engine/AC electric suction fan | POSITIVE/NEGATIVE | Suction fan can be regulated between 20 and 90 %. |
| Ignition circuit shutoff | ON | Engine runs slightly more poorly, recognizable from smooth running. If a fault is present, this exists in the active ignition circuit. |
| Intake manifold switchover | ON | ON: vacuum element (below front engine trim panel) is seen to move. |
| Compression test | For assessing a faulty cylinder. | |
| Compressor clutch Air flap switchover (only when engine off) |
ON ON |
Operates audibly or visibly. Air flap switchover operates audibly. |
| Exhaust flap (cylinder shutoff or T0) | ON | Operates audibly or visibly. |
| Cylinder shutoff | ON | Engine speed drops for a short time and engine runs irregularly. |
ACTUATIONS DESCRIPTION
| Actuations in HHT | Possible symptoms, applications or if no fault is stored regarding | Examples for possible faults in subsystem (refer to Diagnosis Manual Engine Volume 2 - 5 for further remedies) |
|---|---|---|
| Camshaft | Engine vibrates at idle speed, poor output | Camshaft adjustment |
| Air pump | Emissions exceeded | Air line, actuation, lambda control, air pump |
| Injectors | Engine vibrates, poor output | Injector, control module |
| Throttle valve | Engine speed to high, engine vibrates, engine surges | Throttle control stiff, accelerator pedal position sensor |
| Fuel pump | When working on fuel system (drain fuel lines) | For repairs |
| Purge system | Smell of fuel | Purge control valve, line faulty |
| Activated charcoal canister shutoff valve (only USA) | For inspection work on purge system (fuel tank leaks) | |
| Exhaust gas recirculation | Engine vibrates when idling, high fuel consumption | Exhaust gas recirculation valve (jamming) |
| Mixture adaptation | Transition fault, warming-up fault | Ignition system, unmetered air, injector |
| Smooth running shutoff threshold | Engine vibrates | Ignition system, injection system, engine mechanical systems |
| Engine/AC electric suction fan | Engine becomes too warm | Fan faulty, control module faulty, wiring |
| Ignition circuit shutoff | Engine vibrates, poor output | Ignition coil, spark plugs, wiring |
| Intake manifold switchover | Poor output | Switchover valve, vacuum line, vacuum unit |
| Compression test | Engine vibrates, engine difficult to start, poor output | Mechanical fault |
| Compressor | Poor output | Compressor, recirculated air flap actuator, control module |
| Compressor clutch | Poor output | Compressor, line, control module |
| Air flap switchover | Poor output | Actuator, control module |
| Exhaust flap (only T0) | Excessively high emission levels | Vacuum system, exhaust flap stiff |