2000 Sienna reads code 306 - Toyota Nation Forum : Toyota Car and Truck Forums

vadad23 · 04-03-2006, 07:14 AM

I have a 2000 Toyota Sienna Minivan. I have a check engine light on. I used my OBDII tester to pull the code and it is reading code 306 (misfire cylinder 6).

When I first start the vehicle it runs rough. After it warms up (mid range on the temp gauge), it idles fine, but when floored it doesn’t accelerate smooth (pulses).

The vehicle needed new plugs anyway (90, 000 miles) so I started there and replaced them all. All the old plugs appear to have been burning clean (no fouling). After plug replacement it runs a little better but still trips a code 306 after the computer is reset.

Is the next step plug wires (specifically the one to #6) or could it be a bad injector on #6?. Any help would be appretiated!

ShawnM · 04-03-2006, 06:05 PM

More than likely a Wire issue. I would start there since its the most likely cause and the least expensive. Injector problems are not very common.

Frank@toronto · 04-04-2006, 04:23 PM

Could also be a dirty or faulty fuel injector.

vadad23 · 04-05-2006, 03:27 PM

Well, it had read only code 306. I went ahead and changed out the plug wires, cleared the codes and it ran great once the engine was hot. However, the temp here dropped overnight and now the check engine light is back on. This time I pulled a code 306 again and a code 300 (multiple cylinder missfire). I was looking in a haynes manual and decided to start checking sensors. I started with the MAF sensor and between terminals 4 and 5 I am reading infinity (open circuit). Checked it several times (terminals are clean). Before I change it out (its expensive) any chance it is the coil?

ShawnM · 04-05-2006, 05:59 PM

I would try replacing the coil before the MAF. An open in the MAF sensor will set a MAF code. If the sensor is not reading right you would most likely have system lean codes for bank one and two.

msmall1441 · 04-06-2006, 02:35 PM

I agree, likely to be the wires.

If not, then the only other likely cause for a misfire code without sensor fault is a bad coil. I had one bad coil on my Sienna, so I replaced all three. Only $68 each from Pep Boys Auto.

vadad23 · 04-07-2006, 01:46 PM

Thanks guys for your input. I think I will clear the codes and then swap the coils around. If the cylinder 6 missfire moves to 2 or 4, it should be the coil. I'll post back after I give that a try.

vadad23 · 04-10-2006, 06:29 AM

Thanks for all the help. I swapped coils around and the fault code moved to missfire on cylinder 4. Installed a new coil and everything is right with the world.