[hrvoje-vk]

Greetings everyone,

I'm new on forum and registered here because I was having problems with clogged DPF (BMW 318d, 2006). I successfully managed to resolve problem and wish to share with you guys/girls, maybe this info will be helpful for someone. So, let's start:

Has I said, my car is 318d 2006, never had problems with DPF regeneration, has a matter of fact I never know nothing about regeneration until famous DPF sign popped up on dashboard. I drove the car to local mechanics workshop and they pretty scared my... They said that clogged DPF can make some serious damage to the turbo and engine (its truth) and they recommend cutting off DPF and reprogram the ECU. I don’t like someone to make modifications on BMW’s genuine ECU but if had no other choice… Two local workshops immediately recommend cutting of DPF. The DPF warning light popped up EXACTLY after 9 minutes of driving. Turning the car off and wait for few minutes temporary clears the error (but it stays in ECU) and again after EXACTLY 9mnts  of driving DPF pops up. I did not want to give up without a fight for regen. Cutting of and reprograming was my last option. First I took the car for a long drive as my mechanic suggested to me (with DPF error cleared on ecu) on highway, driving around 4-4.5k rpms for about an hour. No success, DPF light popped up again after 9mnts of driving (even error cleared). So, I make some research on net, also here on forum and realized that regen requires some conditions to be met (e.g. more than ½ fuel in tank, engine temp, high revs, long drive…). I unlocked the dashboard hidden menu (why on earth BMW didn’t installed an engine temp gauge???) and put it on menu nr.7 – engine current temp display. When driving on local roads (cabin heat on, outside temp about 3 degrees Celsius) was 45-55 °C, on highway on 4.5k rpm temp was 60 °C. Obviously thermostat failure. I changed engine main thermostat (about 100$) and the EGR thermostat (about 50$). The car temp was now fine 88-90 °C , also mpg was a little lower. I did not have acces to diagnostic (BOSCH KTS) at the moment so I was not able to clear DPF error. I started the car knowing that I have only 9mnts before error pops up and the little triangle shows by the distance meter. I push the pedal to the carpet (monitoring engine temp) and when it came to 90 °C turned off the car, key pulled out, wait for a fed minutes (it give me extra 9mnts before DPF light shows). Started the engine and drove the car on highway as recommend (full tank, engine temp ok, no error). Soon engine temp raised 91,92,93,94,95,96 stay there some time and then slow falls on 88-90. I drove it about 30mnts and DPF warning light did not popped up. The regen was successful! Later I confirmed it on BMW DIS. So, in my case leaking thermostats did not give a car engine to heat on working temp and that blocked the DPF regen procedure.

I hope that someone can find this problem helpful. As I came from Croatia, sorry on my poor English language… 

[hrvoje-vk]

Here is a c/p from E90 workshop manual about DPF:


Regeneration of diesel particulate filter (only on M57TU in E60/E61) The level of charge of the diesel particulate filter is calculated by the DDE using the operating statuses of the
engine. The diesel particulate filter can be regenerated continuously or cyclically.

• Continuous regeneration: In operating ranges in which the exhaust temperature is higher than the ignition temperature of the soot (>
350 ° C), the soot particulates are immediately converted. This involves the slow oxidation of the soot particulates to carbon monoxide (CO) and carbon dioxide (CO 2 ). The nitrogen dioxide present in the exhaust (NO 2 ) acts as the oxidizing agent. The nitrogen dioxide is formed from nitrogen monoxide (NO) in the oxidation catalytic converter. If the exhaust temperature is insufficient for this process, the soot particulates are initially collected and
stored in the diesel particulate filter and then burned off the next time the exhaust temperature is increased.

• Cyclic regeneration: If the driving pattern does not permit continuous regeneration of the diesel particulate filter (e.g. long
periods of low engine load in urban traffic conditions with low exhaust temperatures), selective regeneration
is initiated. This process is controlled by the signals from the exhaust backpressure sensor and the two exhaust
temperature sensors. Like continuous regeneration, cyclic regeneration takes place without any noticeable
effects on vehicle behavior. Dependent on the engine load, the regeneration is performed by selective restriction of the intake air flow in
combination with 1 or 2 post-injection phases. This increases the exhaust temperature to approx. 600 ° C. The remaining oxygen (O 2 ) enables combustion of the soot. The length of the regeneration cycle for the diesel particulate filter may be several minutes. The intervals between regeneration cycles depend on the
conditions under which the vehicle has been operated over the last 500 kilometers. At high exhaust
temperatures, continuous burn-off of soot particulates means that less soot is stored. In addition, the diesel particulate filter is regenerated every 700 to 2,500 kilometers (depending on driving
pattern). If the exhaust backpressure sensor or one of the exhaust temperature sensors fails, the diesel
particulate filter is regenerated every 500 kilometers.

3 Series E90 318d workshop manual can be founded here .