Sunday, April 29, 2012

2001 Toyota 4Runner: Vehicle started skipping Badly?

The Vehicle started Skipping and Check engine light comes ON.
In getting the computer  scanned,most of time Vehicle misfire cores are retrieved.
The Error code P0303 and P1135 are retrieved in some cases.

First try basics to clear the code.
That is remove the negative battery terminal and clear the codes do they come back right away.

In many other cases the Drivers have mentioned that vehicle misfire when engine is idling it sputters and has no take off power.

On all that basis i suggest you few helpful troubleshooting tips and procedure to be tried.

The first thing you can try is to swap one of the coil packs with another cylinder to see if the misfire follows. Usually when a coil pack fails you will get two misfire codes because one coil pack controls two cylinders. If you still get the P0303 then the misfire is isolated to cylinder number three which is the middle bank on the passenger side. At this point you would need to do a compression test to confirm that you have at least 150 psi in each cylinder.
The next thing to test and check is the injector. You could possibly swap the injectors from cylinder three to cylinder one to see if the misfire follows, if you do not have the test equipment to do a balance test on the injectors or flow test.

NOW,Regarding the code 1135 this refers to the air fuel ratio sensor heater which is only used in the California specification vehicle in 2001. There is a heater element built into the air fuel ratio sensor. The air fuel ratio sensor is not the same as an oxygen sensor they are a lot more expensive and will not interchange.

The P1135 is a low current malfunction on the AFR heater circuit of bank 1 sensor 1. Ideally you need to test the voltage at the computer Pin HTAF it should read 12 volts. With in a minute or two the voltage should drop to 0 to 2 volts when the computer turns the ground circuit on to energize the circuit and heat up the sensor. Then it will toggle between 5 to 10 volts depending on the heater circuit demand. If the voltage is not 12 volts then you need to check the voltage at the sensor. If the computer never drops the voltage then the driver is bad in the computer. In most of cases the AFR sensor is bad but in some rare cases I have seen them take out the computer also. If you decide to change the air fuel ratio sensor yourself if the sensor cracks loose then gets very tight as if it is frozen into the pipe do not force it. Use some brake fluid and squirt brake fluid on the threads at the base of the sensor and on the pipe. Let it soak for little bit then work the sensor back and forth and it will come right out. This is a little secret trick I use, yes I did say brake fluid.

The error code P1135 has nothing to do with the skipping problem.

If you have a scan tool or the ability to monitor the air fuel ratio sensor voltage it will actually be working. Without the air fuel ratio sensor heater working as the code indicates it just takes longer for the air fuel ratio sensor to come online to send the computer into closed loop operations. If the air fuel ratio sensor was not working at all you also would have an additional code showing a range or performance problem. This normally will be followed by a lean condition code or a rich condition code depending on how the sensor was biased.

The AFR sensor itself is not too difficult to replace. Normally you can buy a good DENSO air fuel ratio sensor for about $170 in the aftermarket. Make sure you use a DENSO and not a Bosch sensor. If you want a factory sensor go to  for wholesale prices. The aftermarket DENSO is the exact same sensor that Toyota uses.

This all details will help you to trace/ inspect and confirm the problem.

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