what does the code p0305 and p0740 mean on a pontiac grand prixx gt

Asked by Apr 07, 2017 at 11:58 PM about the 2005 Pontiac Grand Prix

Question type: Maintenance & Repair

2 Answers


P0305 is misfire on cylinder number 5 and P0740 is torque converter clutch circuit malfunction. The torque converter clutch is in the transmission. HTH. -Jim


Before pulling that torque converter clutch go threw the wiring to the trans, sometimes its just a exposed wire touching & rubbing on metal. The misfire; check the spark plug for resistance and see if its running rich/lean/hot/oily/moisture on it ect, test coil for low/no voltage out to that cylinder, look for oily coil & cracks or swelling plastic casing(if coil usually will be 2 cylinders are misfiring), check/replace the wire set to spark plugs if one is bad, fuel injector weak or leaky may need cleaned or replaced or its wire harness is shorted/open/connector loose/dirty. Vacuum leak on intake manifold near that cylinder, Worn Rings/Valve Seals,

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