I once had a p0037 code for B1S2 . When I tested the heater , I got an open circuit. As a reference I tested the heater of a good sensor and got 14.3 ohms. I replaced the faulty sensor. I am sorry I cannot be of much help here except to say that it seems that its got to be something common to all sensors . What specifically, I don't know. When you do find out kindly post the solution. This makes the forum work and by the way Welcome to Sienna Chat.

 

Subscribed, I'd like to know the answer here as well.
Also - are all the O2 sensors the same or is the B1S2 its own unique part number?

 

I am having a similar problem but not nearly as bad. Hopefully easier to fix.

I am only getting P0037, which is low voltage on the heater circuit for bank 1 sensor 2. When I unplug the sensor and check for juice on the heater positive lead, I get it. A nice 12V with the key on. However, when I then check for continuity between the other heater wire(which on the harness is red with a yellow stripe) and ground, I get nothing. This wire should be the ground wire, so should be connected to ground.

I traced that red/yellow wire back to the ECU, and according to the wiring diagram linked below, it is pin 25, which would make sense from where it is located on its particular plug:

http://repairguide.autozone.com/zne...pair_guide_content/en_us/images/0996b43f/80/25/62/2b/large/0996b43f8025622b.gif

So my question is, what does that do once inside the ECU? Under normal circumstances, does pin 25 just connect to ground, and for some reason that connection has gone bad here? Is it a connection that is switched on and off inside the ECU on power up, and the switch is not working? I suspect it is not switched since the 12V+ on the other wire is switched, and it would be unnecessary to have a switch on both. I verified this by checking the 12V+ wire with the key on and off and it does turn off with the key.

So if the wire inside the ECU does simply connect to a big ground, would I hurt anything by simply running a jumper wire from the red/yellow wire to ground? It does raise the question that if that were possible, then why doesn't the manufacturer just skip the ground wire and just use the exhaust as a ground. So maybe not a good idea.

Any wisdom would be appreciated.

Have a good one,
Bill

 

Heated air/fuel and oxygen sensors use resistance heating to get to operating temperature quickly. But once the exhaust is hot enough the ECU turns the heater off.

 

I have a 2004 Toyota Sienna LE and this VAN consumes fuel terribly. I did a scan and the result showed the following codes: P0037(HO2S Heater Control Circuit Low B1S2), P0057((HO2S Heater Control Circuit Low B2S2), P2241(O2 Sensor Pumping Current Circuit Low B2S1) and P2238(O2 Sensor Pumping Current Circuit Low B1S1). At first I thought of replacing all the sensors but after doing some research online I decided to test the sensors and their wiring harnesses. My test result showed that all the sensors are doing just fine and that the problem lies with their wiring harnesses.

1. The A/F Sensor B2S1 has a resistance of around 3.2 Ohm and a voltage of around 3.3V but it's wiring harness does not supply heater GROUND to the sensor as the heater power does.

2. The A/F Sensor B1S1 has a resistance of around 2.6 Ohm and a voltage of around 3.8V but it's wiring harness does not supply heater GROUND to the sensor as the heater power does.

3. The O2 Sensor B1S2 has a resistance of around 13.2 Ohm and a voltage of around 0.035V but it's wiring harness does not supply heater POWER to the sensor as the heater GROUND does-I guess that's why its voltage is this low, far below the specified voltage range of 0.1 to 0.9

4. The O2 Sensor B2S2 has a resistance of around 13.6 Ohm and a voltage of around 0.035V but it's wiring harness does not supply heater POWER to the sensor as the heater GROUND does-I guess that's why its voltage is this low, far below the specified voltage range of 0.1 to 0.9

Este voltaje irrazonablemente bajo en el sensor de O2 amplía el pulso del inyector sin razón, me hicieron entender y, por lo tanto, la razón detrás del consumo excesivo de combustible por parte del automóvil.

Por favor, ¿puede alguien de aquí proporcionar una solución a estas TIERRA DE CALENTADOR DE FALTA para los sensores A / F y POTENCIA DE CALENTADOR DE FALTA para los sensores de O2. Gracias por una respuesta esperada.
[/CITAR]
Entonces el problema?

 

Maybe the EFI Relay in the relay box under the hood. You could switch that relay with the horn relay to see if it is bad. You will note several of those relays are identical.

 

1. The original post is 4 years old. I think he's either moved on or solved the problem.
2. Relays are not going to solve a ground problem. He has a ground problem.

 

I have a 2004 Toyota Sienna LE and this VAN consumes fuel terribly. I did a scan and the result showed the following codes: P0037(HO2S Heater Control Circuit Low B1S2), P0057((HO2S Heater Control Circuit Low B2S2), P2241(O2 Sensor Pumping Current Circuit Low B2S1) and P2238(O2 Sensor Pumping Current Circuit Low B1S1). At first I thought of replacing all the sensors but after doing some research online I decided to test the sensors and their wiring harnesses. My test result showed that all the sensors are doing just fine and that the problem lies with their wiring harnesses.

1. The A/F Sensor B2S1 has a resistance of around 3.2 Ohm and a voltage of around 3.3V but it's wiring harness does not supply heater GROUND to the sensor as the heater power does.

2. The A/F Sensor B1S1 has a resistance of around 2.6 Ohm and a voltage of around 3.8V but it's wiring harness does not supply heater GROUND to the sensor as the heater power does.

3. The O2 Sensor B1S2 has a resistance of around 13.2 Ohm and a voltage of around 0.035V but it's wiring harness does not supply heater POWER to the sensor as the heater GROUND does-I guess that's why its voltage is this low, far below the specified voltage range of 0.1 to 0.9

4. The O2 Sensor B2S2 has a resistance of around 13.6 Ohm and a voltage of around 0.035V but it's wiring harness does not supply heater POWER to the sensor as the heater GROUND does-I guess that's why its voltage is this low, far below the specified voltage range of 0.1 to 0.9

This unreasonably low voltage in the O2 sensor widens the Injector Pulse unreasonably, I was made to understand, and hence, the reason behind the excessive fuel consumption by the car.

Please, can anyone out here provide a solution to these MISSING HEATER GROUND to the A/F Sensors and MISSING HEATER POWER to the O2 Sensors. Thanks for an expected response.

 

The O2 sensor is like a battery and and generates voltage when hot to ground for the PCM. The air fuel sensor is like a resistor when hot and controls current to the PCM. The Toyota sienna has 2 A/F sensors- one on B1S1 and one on B2S1. It has one O2 sensor post cat converter.- B1S2. I believe that the O2 sensor switches on and off rapidly and the A/F sensor is steady output. Good luck.