Jan 132017

Toyota CamryI have a 2000 Toyota Camry. Last night the temperature was -10 degrees. I started my car and drove about a block, then got out of the car to let it warm up with the heater on high. About 10 minutes later, I came back to find the engine had died but the heater still blowing. There was power and it sounded as though it should start but something was missing, like spark to gas or alternator weak? Please help..


You will need to make sure you have a fully charged battery. You may also need to get it inside a warm garage to thaw. Make sure it just didn’t run out of gas. You will need to determine what the engine is not getting when it will not start. You can try spraying starting fluid in the air filter while someone holds the gas pedal at least half way down and cranks the engine over. If it tries to start you know it is a fuel related issue.  Further diagnostics may be necessary. I have a wonderful diagnostic chart available online.

Jan 112017

2006 Toyota AvalonI have a 06 toyota avalon, lost power, was told by auto zone it was the alternator. The battery was just purchased 2 months prior. The alternator was less than 1 year old and under warranty with Monroe muffler. The alternator was replaced and I purchased another battery. The battery light still on solid. So I called 4 shops and they all say the alternator is still a bad one. I brought it to Mr. Tire who also validated the warranty and replaced the alternator yet again. The battery light still on so Mr. Tire called tech support, ran tests and said I need an electrical specialist. Have you ever heard of this issue before? any help is appreciated.



Sure, I have heard of this before. This can happen quite often with Autozone “reman” alternators. The good thing is Autozone will stand behind the part warranty but the bad news is they don’t cover the labor in most cases.

However the alternator may be just fine. It may in fact be a wiring harness issue or an electrical connection. With your vehicle being 10 years old it can have all kinds of issues. We will focus on the battery light being on. When the battery light is illuminated it is telling you the battery is not being charged. This can happen sometimes when the battery has an internal short. Luckily you have replaced it and know that is not the case here. It is still possible that the alternator could be bad but after replacing several in a row, I would think at least one of them was good. So that leaves us with the connections between the alternator and the battery.

What to Check

There are 4 small fuses to check and 1 Large fuses to check(depending if you have the smart key option or not). Also 1 main fusible link. My guess would be the Main Fusible link is bad. These fuses are what I would check first. This is of course assuming there isn’t a bunch of corrosion on the battery connections or cables. Only after these fuses check out would I start checking the wiring harness and connections tot he alternator.

I will provide you with a wiring diagram so it may be easier to understand.

Charging System Wiring Diagram 2006 Toyota Avalon

Jan 062017

2002 Toyota CamryOK so it all started off with my check engine light coming on and that was for the two oxygen sensors (top and bottom) which I haven’t changed. It was running okay for a good 5 months until it suddenly didn’t turn on one day due to the starter. I changed the starter and then about 2 months later the car started jerking back and forth and not accelerating uphill. I thought it was the transmission at first, especially after it finally wouldn’t go more than 30 mph. And that was on a good run.

My car is at 230 thousand miles. So my friend didn’t think that was it since his computer read it was one of the coils. We changed one of the coils, nothing. Then changed the spark plugs, nothing. Then finally the mass air flow sensor and bam. It started working again perfectly. Ran a good two weeks and all of a sudden my car started to jerk again really hard. Have I mentioned that my top motor mount is cracked too, eek.  It suddenly turned off and so I cleaned out the mass air flow sensor and it started up again. It ran okay for a few minutes before I had to park.

Now… what happens is that the car turns on OK and doesn’t stall or anything… UNTIL I shift it onto Drive. Reverse and Neutral and Park are OK it seems to be just when I shift it onto Drive and what happens is that it turns off. The whole car completely off. I cant move or accelerate or anything. Won’t budge. I even went back to get a brand new mass air flow sensor(remanufactured though) thinking maybe it was a faulty part I was sold but nothing. Any ideas? Help! lol


I would start by replacing the upstream oxygen sensor(A/F Sensor) since you have a code for it. The upstream oxygen sensor is what tells the computer it needs more or less fuel based upon the burn.  The downstream just lets you know if the catalytic converter is doing it job and has no effect on drivability whatsoever. Also if you have any other codes it would be a good idea to look into each one of those codes. Post the codes below and I will be able to give you more information on each.

Dec 222016

Toyota PickupI have charging problem. Bought new battery, new alternator and new voltage regulator. The plug that comes off the back of alternator is missing. Someone has removed it. I have three wires green, yellow and a black/white on back of alternator the letters E,F,n what wire goes where?


I will provide you with a wiring diagram for the charging system to see if this helps to figure out what wires go where.

1983 Toyota Pick up Charging system wiring diagram


Dec 122016

1994 Toyota Corolla idlingI have a problem with my car’s idling. Every morning the idling goes down instead of going up. What could be the cause of it?


Under normal circumstances the engine idle would go up when first started with a cold engine. This happens because the engine has an ECT (Engine Coolant Temperature) Sensor that lets the engines computer know the engine is cold. When the ECT reads cold it will increase the amount of fuel. As the engines temperature increases the it may reduce the amount of fuel. So what does this mean? If the ECT is stuck or giving a false reading the engines computer may think it is already warm.


Dec 122016

2012 Toyota PriusI have a 2012 Toyota Prius V. As I am traveling along my engine accelerates or engine revs. The only way for me to stop this is to step on the gas pedal.


I consider this as a severe safety issue. Sounds like your accelerator is sticking. This may be from a faulty accelerator pedal sensor. Testing will require a capable scan tool. You may need to take this to a Toyota dealer because not every local shop will have one for a Prius.

Accelerator Pedal Sensor On-Vehicle Inspection


(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Hybrid Control / Data List / Accel Pedal Pos #1, Accel Pedal Pos #2.

(e) Read the Data List.


Tester Display

Accelerator Pedal Condition

Specified Condition

Accel Pedal Pos #1

Not depressed

(8 to 28%) 0.4 to 1.4 V

Fully depressed

(62 to 92%) 3.1 to 4.6 V

Not depressed → Fully depressed → Not depressed (Accelerator pedal should be operated slowly)

Value changes progressively as shown in the illustration

Accel Pedal Pos #2

Not depressed

(20 to 44%) 1.0 to 2.2 V

Fully depressed

(78 to 100%) 3.9 to 5.0 V

Not depressed → Fully depressed → Not depressed (Accelerator pedal should be operated slowly)

Value changes progressively as shown in the illustration

Remove Accelerator Pedal Assembly

accelerator pedal sensor
(a) Disconnect the accelerator pedal assembly connector.
(b) Remove the 2 bolts and accelerator pedal assembly.

Nov 252016

2004 Toyota Corollaon a 2004 Toyota Corolla with 182,00 miles…when i took the car to the shop about 2 months ago and the car had code p0133, p0420 and p0171..the mechanic tells me if i install a new oxygen sensor the codes will probably clear. so i had a new o2 sensor installed..3 days later i get just the p0420.. since its expensive to install a new catalytic converter I Drive the car like that for a month , try to save money..about 5 days ago i notice now i have the p0133 and the p0420 again, I Take it back to the shop since the oxygen sensor is under warranty. The mechanic tells me its best to install a catalytic converter. that the codes might clear, but i always thought u have to clear the p0133 b4 installing the sensor..is he giving me the run-around?


The codes do not have to be cleared before installing a sensor. Generally the codes are cleared after the sensor or parts are installed and tested. You stated above that the code p0133 had gone 3 days after the O2 Sensor was replaced. So the code was gone(cleared). The Code P0420 usually means you need to replace the catalytic converter. The converter does absolutely nothing for the drivability of the vehicle. This is for Government mandated emissions only. You do not have to replace the converter but the check engine light will remain on for the code p0420 until you do.

When the P0171 is combined with the P0174 code, it’s very likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replace the air filter and clean the Mass Air Flow Sensor. If the problem persist the front oxygen (O2) sensor may need to be replaced. Also replacing the converter will not fix the code p0133. The mechanic said it MIGHT which leaves you open for IT MIGHT NOT. Therefore I would say NO to the converter until the P0133 code is taking care of unless you want to of course.

I think your mechanic is trying to help you clear the codes but I also think your mechanic may be overlooking a possible intake air leak. Or there may be something more involved. There may be a damaged wire in the O2 Sensor circuit itself. And it is possible the o2 sensor is bad, but it can be checked with a scan tool. I would assume the o2 Sensor operation was checked since you took it back in for warranty purposes.

Code Information

The P0420 code means that the vehicle’s control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0420 code is combined with other codes, try fixing the other codes first.

Toyota Code P0133 – HO2S11 Circuit Slow Response

Possible causes
– Faulty Front Heated Oxygen Sensor Bank 1
– Front Heated Oxygen Sensor Bank 1 harness is open or shorted
– Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection
– Inappropriate fuel pressure
– Faulty fuel injectors
– Intake air leaks may be faulty
– Exhaust gas leaks
Toyota Code P0133 Description

The front heated oxygen sensor (or O2 sensor 1) is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. A heated oxygen sensor 1 signal is sent to the Engine Control Module (ECM). The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.

Toyota Code P0171- Air/Fuel Mixture System Lean Bank 1

Possible causes
– Intake air leaks
– Faulty front heated oxygen sensor
– Ignition misfiring
– Faulty fuel injectors
– Exhaust gas leaks
– Incorrect fuel pressure
– Lack of fuel
– Faulty Mass Air Flow (MAF) sensor
– Incorrect Positive Crankcase Ventilation (PCV) hose connection

Toyota Code P0420 – Catalyst System Efficiency Below Threshold Bank 1

Possible causes
– Three way catalyst converter Bank 1
– Exhaust tube
– Intake air leaks
– Fuel injectors may be faulty
– Fuel injector leaks
– Spark plugs may be faulty
– Improper ignition timing
– Engine Control Module (ECM)
Nov 222016

1998 Toyota AvalonNo Starter engagement. Using wiring diagram from Toyota, I can jump over ST relay sending current from terminal 3 to 5 will crank. I suspect Neutral/Safety Sw, wiring diagram shows 2 terminals, but actually have 8 terminals on Sw. Willing to pay for quick response. HArold


The Neutral switch may have eight wires but only the two wires shown on the starting system diagram have to do with it starting. The Black/White wire and the Black/Red wire. However there are several fuses to check as well as the starter relay. The starter relay is the most common failure component. You can rule out the theft deterrent system as it shuts off the fuel system, not the starter.

You should see battery voltage at PIN#5 on the starter relay at all times. If not check the Main 40 amp fuse, the AM2 30 amp fuse, the ALT 120 amp fuse and the main fusible link.

You should see battery negative on PIN#2 of the starter relay at all times. Also should see battery voltage at PIN#1 (Black/Red wire coming from neutral switch) only when the ignition key is held in the “START” position.

You should see battery voltage leaving the relay on PIN#3 only when the relay is activated by battery voltage being applied at PIN#1. This will cause starter engagement. If this does not occur and all voltages check out. Replace the relay.

Starting System Wiring Diagram 1998 Toyota Avalon