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P0300 Engine code

13K views 6 replies 4 participants last post by  JuneBug 
#1 · (Edited)
P0300 and MORE codes

Hi All,

So I plugged in my scanner to see what's up with the Rav4, hoping to catch something. My vehicle has been running a bit sluggish for a bit and I really didn't know why. I've got just over 160,000KM on there. Still on the original plugs so will be swapping those out soon. I know they can last a bit longer but why wait? Also my fuel mileage has dropped off noticeably as well. Losing about 40km per tank.

Anyways, while doing an inspection under the hood, I noticed one of the wires were chewed (partially), but enough to severe parts of the wire. The wire leads to the connector on the fuel injector.

I've attached a picture for reference. It's the one on the passenger side if you are looking at the vehicle from the front.

Can I just do a wire repair by splicing it? I know these wires are sensitive to voltage drops. I can either do a solder or I have connectors that will work nicely. Any thoughts?

Vehicle info:

2007 Toyota RAV4 Sport V6

Thanks in advance!
 

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#2 ·
If some strands are broken you can just solder it. No voltage worries.
 
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#3 ·
ok so...ran a diagnostic on the Rav after and came up with a bunch of other codes as well. The P0300 code still remains. That Tundra is starting to look very nice on my driveway...LOL!!!

Forgot to reconnect the connector after I was done with the soldering. Ooops! Came up with a misfire on cylinder 2 but that's all good now. Cleared the code and it's been fine, no more CEL.

I got a bunch of other codes when I went into advanced DTC. I have an INNOVA 3100 code reader. I should note that the check engine light did not come on for those issues. I have noticed that my car does not run with as much power. There is some hesitation at times and my fuel mileage has taken a bit of a hit.

I read through some of the code descriptions and am a bit overwhelmed by it. So first order of business is to clean the MAF sensor to see if that helps with any of the codes. If it does not, would you guys recommend replacing the sensor? Keep in mind, I also have not changed the spark plugs yet. I am at 162,000 km. If I replaced the plugs, would it help with some of these codes?

Today, I had the car at the dealer for a few recall items. They checked the waterpump, stated it is not leaking. On startup, there is a rattle sound (like the paint can rattle) at times. It's not consistent and happens very randomly. A couple of the codes below mentioned the thermostat. The vehicle is 9 years old and is still on the original thermostat.

I'd like to try a few simple things first before diving into the more complex and expensive ventures (02 sensors and CAT). I am hoping to do most of the work myself if I can. I know this is a very long list...

P0430 - catalyst System Efficiency Below Threshold Bank 2

P0171 - Air/Fuel Mixture System Lean Bank 1

P0172 - System Too Rich Bank 1

P0174 - Air/Fuel Mixture System Too Lean Bank 2

P0175 - System Too Rich Bank 2

P0057 - Oxygen Sensor Heater Control Circuit Low Bank 2 Sensor 2

P0058 - Oxygen Sensor Heater Control Circuit High Bank 2 Sensor 2

P0100 - Mass or Volume Air Flow Circuit

P0101 - Mass Air Flow Circuit Range/Performance

P0102 - Mass or Volume Air Flow Circuit Low Input

P0103 - Mass or Volume Air Flow Circuit High Input

P0125 - Insufficient Coolant Temperature for Closed Loop Fuel Control

P0128 - Coolant Thermostat

P0141 - O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 2

P0161 - Oxygen Sensor Heater Circuit Malfunction Bank 2 Sensor 2

P0335 - Crankshaft Position Sensor 'A' Circuit

P0420 - Catalyst System Efficiency Below Threshold Bank 1
 
#4 ·
I would not try to "fix" all those other codes because there is no problem...the rav's computer will find abnormalities and store them in the computer...you only need to worry when the check engine light is on...that means a problem has been detected and it's not going away...I would do normal maintenance and leave it at that...the slight drop in mileage could be from several things such as gas quality or tire pressure...
 
#5 ·
As mentioned it's likely many of the codes may have been set by some one-time anomaly. Dealers must love that. "Just leave us your car and several credit cards sir."
My approach is to reset the codes and see which ones come back. Many may not. Then change the spark plugs and repeat.
 
#6 ·
well the dealer was pretty good about the not replacing parts! They checked the waterpump and the cv joint...advised not to replace. Even though both make noise. And I wouldn't be rushing to do it anyway as it's not that bad yet.

I'll try the spark plugs first and see. As for the fuel mileage, it's significant enough to raise some eyebrows as I've been going to the same gas station and have not changed anything. The tires are all properly inflated. I think what I may do is replace the three coils in the rear as a preventative measure. I don't want to go through a second round of removing the intake manifold again. At the same time, I'll replace the seals on the intake manifold and clean out the throttle body as well. I'll at least have three extra coils I can use if and when the front three decide to pack it in.

As for the thermostat...keep it in or replace it? I think it maybe easy to get to...then again I'll be almost halfway to the waterpump!

I did reset the codes but they are all in pending state...all of them came back after a couple of on off runs.

Thanks for the replies, appreciate the help with all this!
 
#7 ·
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