I have just had same problem...3 days ago the engine, traction control, warning triangle lights all came on along with check vsc and car went into limp mode. Phoned Lexus dealer who could only get me in 5 days later so made appt but in mean time booked into local independent just to run diagnostics. Code came up as DPF blocked. They cleared the coed, ran at high revs for 10 mins hoping this might cure but warned me that fault/limp mode may return. Sure enough a mile or so later and back to square one except I knew what the prob was. A bit of research on interweb and the possible financial implications of filter replacement hit home. Cut a long one short, headed off down to local Wilco and bought a bottle of DPF cleaner, removed and cleaned EGR valve. Drove to nearest dual carriageway (Having to stop/start engine on way to take out of limp mode) and then proceeded to drive up and down the one mile stretch in high revs. (Found 3rd gear 4000rpm the most effective). It took a while as each time the car returned to limp mode had to pull over to stop/start again, but each time I done this the distance between limp modes grew until, after running for 20 miles with no limp mode I returned home, disconnected/reconnected the - lead of the battery (to clear the fault lights etc.) and so far (50 miles +) have no further probe, In fact car is sounding/performing better. Its all to do with urban driving and no fuel additives which means the exhaust doesn't reach adequate temp to burn off the carbon and so it sits in the filter until it blocks.
