EGR VALVE ACTUATOR FAILURE
When this problem occurs, it is likely that the engine management warning lamp will be illuminated. Also, depending on the position in which the actuator has failed, a lack of power will almost certainly also be evident.
Carrying out a diagnostic check may reveal a wide variety of possible fault codes (too many to list here in totality). Here are some examples of the codes that may appear:
P0403 ‘Exhaust gas recirculation (EGR) circuit malfunction’, with possible causes of the trouble including the wiring, the EGR (Exhaust Gas Recirculation) solenoid and the ECM (Engine Control Module).
P042E ‘EGR valve actuator – stuck open’, possible culprits being the wiring, EGR valve actuator, the ECM or a mechanical problem.
P042F ‘EGR valve actuator – stuck closed’, possible culprits being the wiring, EGR valve actuator, the ECM or a mechanical problem.
P04FA ‘EGR – a component or system over-temperature condition’, possible reasons being traceable to the EGR cooler or EGR valve.
Inevitably the fault will lie with the EGR valve actuator. If available on your diagnostic equipment, in ‘special functions’, select ‘EGR’, then activate… This takes over the ECU and operates the valves. You should hear and see movement; a simple resistance check on Pins 1 and 5 with the connector disconnected should show 4 ohms – anything higher than this will indicate a failure.
Edward advises that renewal of the actuator is fairly easy, but you have to carry out a ‘teaching’ process once the new unit has been fitted.
DIESEL PARTICULATE FILTER (DPF)
In this problematic situation, the car’s driver will almost certainly notice a lack of power and engine management difficulties, with the DPF warning light illuminated, and with fault codes C1B14 and C1B15 stored.
The sensor can do funny things when it fails; you have to remember its purpose is to tell the ECU how full the DPF is, via a pressure to voltage signal. So, it’s possible it might be regenerating more often than it should, or to the untrained eye a new DPF filter will need to be fitted.
Firstly, if available look at live data… in Edward’s experience the signals jump around. It’s also possible that by using a multimeter you can check the signalling. Remember that the higher the voltage the more blocked the filter is, ie. 0 volts means ‘empty’; 5 volts indicates ‘blocked’. Always fit good quality new sensors – there are many poorly manufactured copies available, and they can cause more trouble than good.
Fault 3: FAILED GLOW PLUGS
This is a problem that almost certainly won’t produce any lack of power but if the fault is left to its own devices it will create a problem in terms of the DPF filling and blocking…
The fault lies with the glow plugs. You have to remember that modern systems won’t carry out a regeneration while faults are stored in the engine control system. Widely, people are of the mindset that because the car is starting OK the glow plugs don’t need to be renewed.
However… Yes, glow plugs, in certain temperature ranges, help cold starting and they aid emission reductions, but this is not the whole story…
Carrying out a fault code check will show a fault code for the failed cylinder; be wary if you have codes set for all the cylinders as this can be a red herring and a fault with the controller. Note that a single cylinder code relates to the glow plug itself.
When testing, the required resistance for a good condition component, working as it should, is 0.4 ohms.
Edward always recommends installing a complete set of glow plugs because it’s likely that if one fails the others might not be far behind.
A good soaking in penetrating fluid before you attempt removal helps ensure a positive result!
HEADLAMP UNIT CONDENSATION
Many examples of the Volvo V40/ford Focus from the era under review suffer from really bad condensation in both the front headlamps – the problem being poor ventilation within the lamp units.
A really simply fix is to remove the rear lamp cover (the one that provides access to the bulbs) and add two small holes for further ventilation –
“This works a treat”, says Edward.