Dustinfox

Anyone know where I can get a list of GM specific trouble codes? 2004 Silverado 4.8 VIN-V showing random misfires P300. But also showing a code "C1601" display says "manufacturer specific." Can't find anything on the web but I Need to know what C1601 code is.

Thanks!

tech2

nothing comes up for me on the prodemand system for c1601

what scan tool are you using?

c codes or chassis codes are for the abs not engine operation. fix the p0300 random misfire...this is a critical dtc...misfires can damage the convertor. if you scan tool has misfire monitors data....use it to isolate the misfire to a specific cylinder or bank of cylinders.

Dustinfox

Hi thanks... I am using a hand held scanner https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1 Trying to track down the cause of the misfires. Not always the same cylinder. Misfires only seem to occur at highway speeds when accelerating. Engine off fuel pressure seems ok at 55 psi but I need to find out if that holds under full throttle. The C1601 has me stumped though.

tech2

try a different scan tool...c1601 is setting from compatibility issues with your cheap scan tool.

monitor fuel trim under load...top gear wot acceleration...if the fuel trim is normal cruising but is adding more than 10% during the top gear roll on...you have a fuel supply problem. if the fuel trim number are all over the place when its misfiring during the roll on....you may have a clogged cat...remove the 2 precat sensors from the exhaust and repeat the test....or put a exhaust backpressure gauge in the 02 hole and measure exhaust backpressure.