My 1995 Maxima with 222,000 miles usually runs like a champ. I am just the second owner and have had the car since it had 130,000 miles. Out of the blue I detected a cylinder wasn’t firing. The check engine light came on so I used the screw on the ECU to pull the codes. I got codes 0603 and 0306 – misfire on #6 cylinder 6 and EGRC/BPT valve. I pulled the #6 coil and plug – the plugs are NGK iridium and were changed at around 180,000 miles. The plug looked fine so I put it back in – I reconnected the coil and using a circuit tester checked it – it was firing fine. I cleared out the codes and went out for a short drive. The car was still missing.

I came back and with the engine running unplugged the coils one by one. I detected some change of RPMs on all cylinders except for #3. I even tried unplugging the front injectors and each one gave a noticeable RPM change. I checked the #3 plug and it looked about like the #6 plug - the coil fired just like the #6. There was no CEL on the dash but I checked again for codes. Now I have 0201 code. I have cleared it but each time it returns even though there’s no CEL on the dash

Finding no RPM change at the #3 cylinder and with a coil that fires fine I was convinced that I had a bad injector. I used an Ohm meter to check the rear injectors using the 8 pin connector and got no Ohm reading from the 1 and 6 pins. 1,2 and 1,5 all showed around 14 or 15 Ohm readings.

I was about to go ahead and pull the UIM and change the #3 injector. However, with the 0201 code showing up I now wonder about this Ignition Signal Circuit. This is confusing – do I have a fuel problem or an ignition problem? The 0201 code is the same as a P1320. The trouble shooting guide says to check among other things the Crankshaft Position Sensor (REF) Circuit.

I am open for any suggestions. It may well be that I have to change both the CPS and the #3 injector. The CPS front and rear have never been changed as far as I know. Thanks in advance for any advice… Be Safe, Mark V.

 

At that kind of mileage that the CPSs are still working at all is some kind of miracle... first, have the injectors cleaned (ultrasonic) and then see how it is.

 

If u getting resistance from the injector then its fine.

Go to the junk yard and pull a coil. The test for a coil in the haynes is a better test than the FSM IMO. Ignition signal is still the coil.

I say u have a bad coil. But the CEL should tell u which coil if its a component failure.
could also be a bad CKPS.

I have hrd of coils having a crack in them that only cause a problem when the engine is warm.

 

Thanks guys for the comments and suggestions. It ended up as expected - failed #3 fuel injector. It wasn't even giving an Ohm reading from the 8 pin connector - so the windings had broken down. I bought one and installed it over the weekend. I am regretting that I did not buy all six injectors. The 0201 code was from my plugging in a coil pack and bending over one of the pin connectors. Stupid mistake - easy fix!

Oh what fun pulling and reinstalling the UIM!!! I have the skinned knuckles to prove it. The two 12mm bolts on the back of the UIM, the C shaped coolant hose, and the bolts on top of the EGR tube - what a PIA... End result though is the Max runs great. I put in some 93 octane and drove about 40 miles - I was having such fun. 70MPH at around 2800 RPM. The VQ30 is back running like a Husqvarna sewing machine. 221,111 showed on the odometer during my test run. Now I have to set aside time for the mother-in-laws 2003 valve cover gasket R&R... Going to do the covers and gaskets using 2004 parts.

Be Safe, Mark V.

 

kewl.