Cleaned the EGR valve in my girlfriend's Sorento today.
Car has been having some issues lately. For a few months, it's been a little lumpy at idle, but only on a cold start, and only if let to idle - as soon as you apply a bit of throttle, it smooths out.
She then rang me in a panic a few weeks ago because the engine management light came on while she was towing and started blinking. No other signs of a problem - apparently sounded fine, no misfires, no smoke, no loss of power. She didn't really want to stop on the M20 with a horse on board, so I told her to just get back to the stables and I'd meet her there. I have a Bluetooth OBD2 dongle, and used the Torque app to read the codes. Turned out to be a DPF problem - P2002, "Particulate Trap efficiency below threshold". Fair enough, it's been doing too many short journeys lately, and it's on nearly 120K miles, so not entirely unexpected. Cleared the code, and it didn't come back. Took it for a long run the next evening after chucking some DPF cleaner in the tank, and have taken it for a few long motorway runs since - light didn't reappear.
She then had to tow again last week. Again, the light came on while towing. However, the next day, before I could clear it manually, it went off after giving the car a bootful on a motorway slip road. Great. Took the car for another long drive at the weekend to see my parents, a nice 100 mile drive at decent speeds. No issues.
A couple of days ago, the light came on again, but this time wasn't blinking. But she also said she lost power a few times. Bugger. She got home, and I pulled the codes - this time, as well as the DPF error, there was one for the EGR (can't remember the exact P code). I cleared the codes and took the car out - no problems.
I knew EGR valves could cause issues sometimes, and this would tally up with the rough cold idle, so today, I took the EGR valve off to give it a clean. Annoyingly, it didn't look too bad - caked in soot, obviously, but no big buildups to speak off. Still, I let it sit in petrol for a while, then scrubbed it with a brush and liberal amounts of brake cleaner. Also sprayed out the part of the exhaust manifold where it sits to get that somewhat clean. I'm hoping that the EGR valve is the main culprit - I know they can cause issues with rough running and loss of power if they are sticking, but apparently, they can also have a knock on effect on the DPF, if they are letting too much exhaust gas recirculate when they shouldn't.
I put the valve back on and after a very rough start (got some of the brake cleaner in the intake tract), it started fine. A quick run up the road and to my mind, it feels a bit smoother, but that could be a total placebo. Time will tell, I guess.
Pictures below.
Bloody diesels :/
