Mil Light On.

[Roadwrangler]

I was on the M6 recently heading to a mates in Stoke doing 70'ish cruise on, knocked the cruise out as I approached some congestion, the instant I knocked the cruise out, the MIL light came on, the car went into Limp Home mode, dropped to about 40mph and all kinds of error messages started flashing past, 4x4 System Error, ABS Error etc I'm thinking WTF happened now. I pulled off the motor way and made my way back home on the A roads about 10 miles.

Once home plugged the Launch code reader in, and pulled out 2 codes both relating to EGR, I can only assume if you have an EGR fault the ecu thinks it can't maintain emmissions so shuts a load of systems down to reduce any emmissions till its fixed. I cleared the codes and started the engine, straight away MIL back on, same codes coming up, repeated this once more and same again. I know my car doesn't have EGR flow monitoring like some later cars do, but it does monitor the relative position of the EGR Valve (or at least the solenoid) All I can think is that when I knocked the cruise out I was going up hill slightly so the engine was under load, knocking the cruise out would have caused a manifold pressure drop as the car instantly changed to deseleration, I'm guessing the EGR valve had a little spasm and a bit of carbon got stuck preventing the valve from closing properly. A few very gentle taps with a nylon faced mallet on the EGR valve body and solenoid, engine started ok, no MIL light and off I went back on my way to Stoke.

About a week later I decided to take the EGR off and clean it, following a conversation with Anchorman last year, this time I decided to fully strip the valve, I knocked the end cap out and removed the internals (2 valve disks, 1 valve seat and the connecting rod) rather than scrape it clean, I used a little ultrasonic cleaning tank, Aldi had them on special offer a few months back, really meant for cleaning jewlery, but they work a treat with degreaser and nuts and bolts, I put all the EGR bits in and poured a bottle of Chevron Injector cleaner into the tank and blasted it with ultrasound for an hour, the carbon came off as easy as wiping grease off a spanner, it was internally like a new one when I'd finished. With all the parts re-fitted its run fine since, no more codes.. If anyone tries this cleaning method, when re-assembing all the bits into the valve body, the 2 valve disks have to be set in position relative to each other before re-fitting the end cap.!

Regards Ausitn..