Toyota 4Runner Issue

PhilFausz · **Posted:** Sun Mar 30, 2008 8:39 pm

Anyone ever run into this? Jessica's 2001 4Runner's check engine light just came on today and after scanning, it returned the following:

Code: P1135 - A/F Sensor Heater Circuit Malfunction (Bank 1 Sensor 1).

Truck has 130,000 miles. I've got the FSM and will be checking that in a few minutes. I just wanted to know if anyone else might have run into the same thing, and also, if there are any good toyota forums to poke around if need be.

Thanks!

Dustin Fredrickson · **Posted:** Sun Mar 30, 2008 8:47 pm

PhilFausz wrote:

Anyone ever run into this? Jessica's 2001 4Runner's check engine light just came on today and after scanning, it returned the following:

Code: P1135 - A/F Sensor Heater Circuit Malfunction (Bank 1 Sensor 1).

Truck has 130,000 miles. I've got the FSM and will be checking that in a few minutes. I just wanted to know if anyone else might have run into the same thing, and also, if there are any good toyota forums to poke around if need be.

Thanks!

Sounds like the (upstream likely) O2 sensor went out - should be a simple replacement to fix. Only think I'd check is that 'Bank 1' is indeed the upstream one, not downstream.

George Bright · **Posted:** Sun Mar 30, 2008 8:57 pm

Bank refers to cylinder bank 1. The FSM should tell you which one is bank 1. Sensor 1 should be the upstram sensor. IF not then you can unplug one of the upstream O2 sensors. If you unplugged the defective one then you will not get another heater code.

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

You need to love the internet.

http://www.google.com/search?q=P1135+4r ... tnG=Search

First hit:

http://www.obdii.com/ubb/Forum1/HTML/002422.html

Quote:

Manufacturer DTC P1135 (for Toyota) means A/F Sensor Heater Circuit Malfunction Bank 1 Sensor 1 (Set when the heater operates, heater current exceeds 8A or heater current of 0.25A or less).

The A/F sensor contains a ECU-controlled heater. At start-up, the heater helps warm the A/F sensors to quickly operating temperature. With minimal exhaust gas flow, the heater keeps the A/F sensor from cooling down.

Take a look http://www.babcox.com/editorial/us/us10226.htm

Checking Resistance.
a. Disconnect the A/F sensor connector.
b. Using an ohmmeter measure the resistance between terminals +B and HT. Resistance: 0.8 - 1.4 ohms at 20�C (68�F). If the resistance is not as specified, replace the sensor.
Torque: 44 Nm (440 kgf.cm, 31 ft.lbf)
c. Reconnect the A/F sensor connector.
(http://www.alflash.narod.ru/O2/79062351.gif )
Quotes.
P0125 set if after the engine is warmed up, A/F Sensor Output* does not change when conditions (a), (b), (c), and (d) continue for at least 1.5 min.:
a. Engine speed: 1,500 rpm or more
b. Vehicle speed: 25 � 62 mph (40 �100 km/h)
c. Throttle valve is not fully closed
d. 140 sec. or more after starting engine
*Output values changes inside ECM only
This DTC can be set due to other related parts failure.

Michael Westerfield · **Posted:** Mon Mar 31, 2008 8:26 am

Phil, just went through this on my pathfinder. I had bank 2, sensor 1 though. In my findings bank 1 is supposed to be the bank that cylinder 1 is on. I also traced the wire back to the ECU to make sure their was continuity before ordering the sensor. I replaced the crappy bosche oem one with a NGK (or NTK) unit that seemed to be well made. Cost me about 60$. No more light...

PhilFausz · **Posted:** Mon Mar 31, 2008 10:48 am

What's funny is that the FSM is describing a completely different issue than the O2 sensor, but most folks on http://www.tundrasolutions.com/ are suggesting the front O2 sensor.

I'm going to drive the truck this week with the diagnostics running and it will tell me what shape the O2 sesnors are in. I'll report back later this week on the solution.

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Toyota 4Runner Issue

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