Toyota engine repair questions and answers
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AutoMD Member - 1998 Toyota Avalon - Engine - 2/20/2014I drive a 1998 Toyota Avalon with approximately 201,000 miles. My check engine light came on last week, so I made an appointment to get it diagnosed and fixed by a mechanic. I asked him what the codes were, he said there were the following codes: 171, 303, 305, 300. ...
2/20/2014 JimmYou can ask to speak with and settle the cost of the previous misdiagnosis with the repair shop manager. Maybe they will agree to refund some or all of the cost - or agree to provide the required repairs for free or greatly reduced cost to you. If not, then you have only one remaining option.....
You can elect to take your business elsewhere - to another shop that will properly diagnose the issue(s) you are having. For example, the Mass Airflow Sensor replacement will not correct any of the misfiring codes; P0300, P0303, P0305, etc.
Here are the fault codes and causes in each case;
P0300 (0303 / 0305) = Cylinder misfiring
For the misfires
It may mean that one or more of the following has happened:
Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
P0171 = System Too Lean (Bank 1)
Basically this means that an oxygen sensor in bank 1 has detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1. The P0171 is one of the more common trouble codes.
This code is triggered by the first downstream (front) O2 sensor. The sensor provides a reading of the air:fuel ratio leaving the engine's cylinders, and the vehicles powertrain/engine control module (PCM/ECM) uses that reading and adjusts to keep the engine running at that optimum ratio of 14.7:1. If something is not right and the PCM cannot maintain the 14.7:1 ratio, but rather there is too much air, it triggers this code.
A code P0171 may mean that one or more of the following has happened:
•The MAF (Mass Air Flow) Sensor is dirty or faulty
Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
•There could be a vacuum leak downstream of the MAF sensor
•Possible cracked vacuum or PCV line/connection
•Faulty or stuck open PCV valve
•Failed or faulty oxygen sensor (bank 1, sensor 1)
•Sticking/plugged or failed fuel injector
•Low fuel pressure (possible plugged/dirty fuel filter!)
•Exhaust leak between engine and first oxygen sensor
A lot of times, cleaning the MAF sensor and finding/fixing vacuum leaks fix the problem. If you're on a tight budget, start there, but that may not be the fix for certain. So, possible solutions include:
•Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with MAF-specific cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
•Inspect all vacuum and PCV hoses, replace/repair as required
•Inspect all hoses and connections in the air intake system
•Inspect and/or test the intake manifold gaskets for leakage
•Check for a dirty fuel filter and proper fuel pressure
•Ideally you'll want to monitor short and long term fuel trims using an advanced scan tool
•If you have access, you may want to run a smoke test
2/20/2014 HouseCallAutoThe real cause is most likely a bad Air Fuel Ratio Sensor bank 1 sensor 1 and replacing the mass air flow sensor with 2 misfire codes present on one bank clearly would not solve the misfires.
AutoMD Member - 2004 Toyota Corolla - Engine - 2/19/2014Please help. My car's radiator/engine temp gauge was hot so my mechanic put 1/2 gal of water in the Radiator . Before that, he said my overheating was due to lack of coolant. My temperature gauge maintained midway temp and he advised me to add coolant in the ...
2/19/2014 HouseCallAutoDo not add it to the reservoir, add directly to the radiator, slowly until the radiator is full. Then start the car and let it idle and when the coolant level begins to get lower in the radiator add more and keep doing that until it does not drop anymore and the coolant should be warm or hot to the touch with dipping your finger into the radiator neck. It can take 5 or 10 minutes of watching for the thermostat to open and the level to drop and all the air to get purged out but it will happen. At some point turn the heater on and confirm that the car is blowing out heated air. It is perfectly ok to run the engine with the radiator cap off for as long as it takes for the cooling system to stabilize and then put cap back on. Also, do you have an idea why the coola nt level was low or why it overheated? It usually means there is a leak someplace. If you just add coolant it will be ok until it leaks down low again and then will overheat again. And yes, the 50/50 will be ok.
AutoMD Member - 2011 Toyota RAV4 - Engine - 2/19/2014Wiring disappears into the frame.
2/19/2014 JimmIs this a question regarding the bank 1 snsor 2 oxygen sensor (O2 sensor) located on the exhaust system? If yes, why would you be concerned with the interior console for the oxygen sensor replacement?
Simply disconnect the old O2 sensor wiring connection at the sensor. Then, using an oxygen sensor deep socket - unscrew / remove the old sensor. Sometimes the old sensors can be corroded - so a spray of thread lubricant to the base of the old sensor (remove the old sensor when the vehicle / engine is cold) and given time to left soak in - will help the removal process.
Be sure to place a light coating of anti-sieze / thread lubricant on the new sensor threads before the installation.
You might reference the 'How-To-Guides' feature on the AutoMD website for the specific steps to changing the O2 sensor.
The parts are readily available from these many on-line sources, www.partsgeek.com, www.rockauto.com, www.discountautoparts.com, www.autopartswarehouse.com, www.jcwhitney.com - to list only a few possibilities.
In fact, they (RockAuto) list the oxygen sensors from around $44.00 for your vehicle.
2/19/2014 HouseCallAutoThe connector I believe is anchored under the console / carpet and unless you remove the console you can't do it. Some vehicles I have run into I was able to pull on the wire and the connector simply went through the access hole after the rubber seal was pulled downward. Not sure if you already tried that but I would try this first. If you do have to remove the console, don't panic or let this stop you BUT do get a detailed manual with the step by step with the pics so that you do not break anything.
AutoMD Member - 2007 Toyota Camry - Engine - 2/18/2014I took my Toyota Camry (69000 milage on vehicle) for engine oil change. They did put any oil in it since there was no sign of oil on the dip stick. I have driven it for 15 mins total of 2 miles local + 8 miles freeway. I saw low engine pressure light flicker on and ...
2/18/2014 HouseCallAutoSomeone else besides the place the did the oil change has to examine this. There could be damage that will not show up now or there could be damage now. Driving 15 minutes with no oil pressure? That can kill an angine quicker than 15 minutes. What matters most here is how many minutes the engine was actually running with you seeing the low oil pressure message. You can be low on oil but not empty and there is a huge difference between the two. No reading on dipstick does not mean totally empty but of course could be. The only thing that may be in your favor here is if it was underfilled (not empty) in which case no damage is likely.
soonersbigb82 - 2003 Toyota Tundra - Engine - 2/16/2014Well where the radiator screws on the housing that the cap screwed on basically fell apart. So I replaced radiatior. Before I replaced it the a/c and heater worked great. But ever since neither the a/c or the heater works. At first I thought it was just the a/c ...
2/16/2014 CVO1.Air pockets trapped in the cooling system can cause the engine to loss their supply of coolant efficiency to the heater core. Some cooling systems have air bleed valves built into the system to aid in the removal of air pockets. Advice: For many cooling systems, the method of removing air pockets is to start the engine and allow it to run with the radiator cap off or loose until all the air escapes from the neck of the radiator. For some systems this method is not sufficient, and the manufacturer has installed air bleed valves usually near or on the thermostat housing.
2. Check the heater hoses run from the engine to the heater core. The return heater hose back to the engine must be hot in order to make the heater core works. In the event, if that hose doesn't get hot then the heater is clogged. Replace the heater core.
AutoMD Member - 1999 Toyota 4Runner - Engine - 2/15/2014Recently my 4runner started vibrating really bad. Mostly when I'm braking and come to a stop or when I'm going a faster speed on the freeway. Check engine light came on I had it checked and it came up with a misfire in cylinder one so I replaced all spark plugs and ...
2/15/2014 HouseCallAutoReplace cylinder #1 fuel injector. This is not a sure thing but if you want to go through the trouble to confirm this without actually having to buy a new $100 injector just yet, try swapping the #1 injector with another cylinder and see if the misfire code moves with the injector to confirm. If it does change to the other cylinder then you can buy a new injector and take the time to buy it online cheaper than the auto parts stores.
AutoMD Member - 2008 Toyota Sienna - Engine - 2/14/2014It dropped from 19 to 17 very slowly and then it suddenly started dropping about 1MPG with each fillup over the past month
2/14/2014 HouseCallAutoUnknown until some data from a professional scanner is viewed and a check for any fault codes. At the very least, confirm the air filter is clean, tires are inflated to correct pressures and clean the mass air flow sensor with dedicated MAF sensor cleaner. How does it run?
AutoMD Member - 1994 Toyota Camry - Engine - 2/14/2014ALL THE ANTIFREEZE WILL BE TROWN OUT OF ENGINE
alanspse - 1989 Toyota Pickup - Engine - 2/13/2014I just had a new exhaust pipe and muffler installed it had plenty of power when the exhaust was broke in front of the converter but now it wont pull out of 2nd gear seems like it's suffocating I didn't have a converter installed to save money and I don't think they ...
2/12/2014 John's Auto RepairWell, then i would take it back since it ran fine before the exhaust work. Obviously, something
in the exhaust is restricted. I would think the Catalytic Converter is fine since it is connected
before the exhaust work.
AutoMD Member - 2003 Toyota Tacoma - Engine - 2/12/2014mileage = 99,000 +. No work done on this problem. Happens pretty much all the time. Happens from any standing stop then to go. I've noticed it for approx. 2 yrs. now. check engine light isn't on. No other warning lights are on.
2/12/2014 John's Auto RepairI would try a new fuel filter. Then check fuel pressure. Also the exhaust could be restricted.
A quick test for this is to remove the Oxygen sensor and test drive. If engine seems to be
running a little better, then somewhere in the exhaust system is restricting exhaust flow.
Typically it's the Catalytic Converter.
AutoMD Member - 2003 Toyota Tacoma - Engine - 2/12/2014mileage = 99000+. No work done yet. Happens all the time. Getting going from a stand still. First noticed it about 2 yrs. ago. No check engine light on. No other lights either.
2/12/2014 HouseCallAutoHave to plug in a code reader and see if any codes are stored even though light is off, codes can still be there. You can obtain a code reader from Amazon.com for around $20 with shipping incl.
2/12/2014 JimmFirst step - have the stored fault codes or check engine light scanned - for free - at any local auto parts store; Advance Auto, Auto Zone, NAPA. Then, post a reply as 'add answer' with the specific code for more assistance. There may be a fault code stored in the OBD memory which may not be displayed as a check engine light.
Possible Causes of Engine Hesitation or Stumble:
Dirty fuel injectors (cleaning the injectors often fixes this)
Dirty air filter (change filter)
Dirty / clogged fuel filter (change filter)
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)
Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:
Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
AutoMD Member - 1991 Toyota Previa - Engine - 2/10/2014fan belt needs to be replaced i want to do it myself. how do I doit? Is there a diagram to show me step by step?
2/10/2014 JimmUse the 'How-To-Guides' feature on the AutoMD website - step-by-step including photos. The parts are readily available from these many on-line sources, www.partsgeek.com, www.rockauto.com, www.discountautoparts.com, www.autopartswarehouse.com, www.jcwhitney.com - to list only a few possibilities.
In fact, they (RockAuto) list the serpentine and other accessory drive belts from around $2.50 (each) for your vehicle
AutoMD Member - 2001 Toyota Corolla - Engine - 2/10/2014tried to take to mechanics , heat gauge went up and turning on hear did not seem to help
AutoMD Member - 1996 Toyota Tercel - Engine - 2/7/2014I have a '96 Toyota Tercel, and I live in Ohio so it's been extremely bitter cold this winter and that's when this problem has started happening. The car is rattling and shaking really loudly whenever I go past 30-40mph, and overall just has issues accelerating. ...
2/7/2014 HouseCallAutoYou need to narrow down some detail for me. I need you to determine if what you are feeling / hearing is a result of the engine running poorly or a result of something relating to the suspension / tires / etc which is a separate thing from the engine. Please better describe what you are hearing feeling so that maybe I can make that determination.
AutoMD Member - 1995 Toyota Camry - Engine - 2/4/2014It started out as our oil pump gasket leak. Now it dies. It doesn't matter if it is cold or warm. I had to replace the distributer cap.