HO2 sensor -heater 2000 Mazda V-6 can't locate sensor site on vehicle? We cannot locate the correct sensor. We have installed several at different locations (6) and the code remains "heater circuit". We have also installed a new catalytic converter. No sensor location is shown.

although the picture is of a 6 cly model the location is the same HO2 sensors are mounted in the exhaust system before and after the catalyst HO2..1 is the up stream Before the cat and HO2...2 is down stream of the cat if your code is bank one sensor 1 its the upstream and bank one sensor 2 is the downstream

Looks like Lambda sensor fault,

Fault Code:- P1646 Indicates a Power-train fault


The fault is generally due to a problem in the Computer & Output Circuit area


Fault Description: ECM HO2 Sensor control malfunction -bank 1 upstream (1/1)

Action of ECM:- ECM Default:- HO1S 1/1 control circuit inhibited


After clearing the DTC, complete the Drive vehicle for 10 minutes
Check for a reoccurrence of fault DTC.

Possible Fault:- HO2 Sensor 1/1 heater failure HO2 Sensor 1/1 sensing circuit: short circuit to ground, short circuit to high voltage, open circuit ECM Failure

See http://www.bluejag.co.uk for more info

Hi there,

An O2 sensor (also known a HEGO or HO2s) is an electrical 'probe' which is screwed into your exhaust pipe/s (you will see an electrical wire connecting into your exhaust pipe).

Each exhaust pipe will have an O2 sensors (sometines 2 per side - one mounted in front of the catalytic converter and one after the converter).

An HO2 sensor is responsible for heating up the exhaust gas (when starting vehicle from cold) to aid the computer in delivering the correctly Fuel/Air mixture. Once the engine reaches normal operating temperature, the heater section on the O2 sensor then turns off, providing normal exhaust gas measurement for appropriate fuel/air mixture.

An HO2 sensor is critical in the efficient running of an engine.

Hope this helps,


Cheers,

Fault Code:- P1647 Indicates a Power-train fault


The fault is generally due to a problem in the Computer & Output Circuit area


Fault Description: ECM HO2 Sensor control malfunction -bank 2 upstream (2/1)

Action of ECM:- ECM Default:- HO2S 2/1 control circuit inhibited


After clearing the DTC, complete the Drive vehicle for 10 minutes
Check for a reoccurrence of fault DTC.

Possible Fault:- HO2 Sensor 2/1 heater failure HO2 Sensor 2/1 sensing circuit: short circuit to ground, short circuit to high voltage, open circuit ECM Failure

Hi there,

P0030 = HO2S Heater Control Circuit (Bank 1 Sensor 1) - No.1 Heated Oxygen sensor on bank 1.
P0036 = HO2S Heater Control Circuit (Bank 1 Sensor 2) - No. 2 Heated Oxygen sensor on bank 1

For both of these to trigger on the same bank, means most likely an Open or Short to Ground condition (somewhere on the Bank 1 circuit) stopping the HO2 sensors from reaching their working temperature.

Check the following in this order:

1) Using a multimeter, check 'continuity' of the Oxygen circuit FUSE terminals (don't rely on visual inspection alone) or replace fuse with a known good one.
2) Check for moisture getting into both oxygen sensor connector terminals (bank 1).
3) Check for good connection at Oxygen sensors (bank 1).
3) Have both heated oxygen sensors on Bank 1 tested (ensure their values are to specification).
4) Check HO2 pin-outs of the PCM for correct voltage.

Only replace the HO2 sensors as a last resort (if out of spec).

Then engine department relay centre & fusebox location is behind the washer bottle, but I believe the HO2 sensors are connected direct to the PCM, not a relay.

Cheers,


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Removal & Installation Upstream HO2 S1 To Remove:
NOTE: If the engine temperature is lower than 120 °F (48 °C), the HO2 S1 sensor may be difficult to remove. Excessive force could possibly damage the threads in the exhaust manifold.

1. If necessary remove the fuel injector cover.
2. Disconnect the HO2 S1 sensor electrical connector.
3. Using an oxygen sensor removal tool carefully remove the heated oxygen sensor.

To Install:

1. Coat the threads of the oxygen sensor with anti-seize compound
2. Install the HO2 S1 sensor. Tighten the HO2 S1 sensor to 30 ft lb (41 Nm).
3. Connect the HO2 S1 sensor connector.
4. If removed, install the fuel injector cover.

Downstream HO2 S2 To Remove:
NOTE: If the engine temperature is lower than 120 °F (48 °C), the H02 S2 sensor may be difficult to remove. Excessive force could possibly damage the threads in the exhaust pipe.

1. Raise and safely support the vehicle.
2. Disconnect the H02 S2 electrical connector.
3. Using an oxygen sensor tool carefully remove the H02 S2.

To Install:

1. Coat the threads of the H02 S2 with anti-seize compound.
2. Using an oxygen sensor tool install the H02 S2. Tighten the sensor to 30 ft lb (41 Nm).
3. Connect the H02 S2 sensor electrical connector.
4. Lower the vehicle.

Oxygen Sensor
Removal & Installation
CAUTION
The oxygen sensor in-line connector and
louvered end must be kept clear of grease, dirt or other contaminants. Avoid
using cleaning solvents of any type. DO NOT drop or roughly handle the oxygen
sensor.
The oxygen sensor may be difficult to remove when the engine
temperature is less than 48°C (120°F)

NOTE: Removal of the oxygen sensor is
easier when the engine temperature is above 48°C (120°F).

Upstream HO2S Sensor
To Remove:

1. Before servicing the vehicle refer to the Cautions and
   Warnings at the beginning of this section.
   
2. Raise and safely support the vehicle.
   
3. Remove or disconnect the following:
   
   
   
   • Electrical harness connector (A) from the HO2 S.
     
   • Remove the HO2 S (B) using special service tool
     J39194-B.

To Install:

CAUTION
GM uses a special anti-seize compound on the
HO2S threads. The compound consists of liquid graphite and glass
beads. The graphite tends to burn away but the glass beads remain easing sensor
removal. New or service replacement sensors have the anti-seize compound already
applied to the threads. If the sensor is removed from an exhaust component and
if for any reason the sensor is to be reinstalled the threads must have
anti-seize compound applied before installation.

1. Coat the HO2 S threads with GM P/N 5613695
   high-temperature anti-seize compound as needed.
   
2. Install the HO2 S using special service tool
   J39194-B;
   
   
   
   • Torque to 31 ft-lbs (42 Nm).
   
   
3. Connect the HO2 S electrical harness connector.
   
4. Lower the vehicle to the ground.

Downstream HO2S Sensor
To Remove:

1. Before servicing the vehicle refer to the Cautions and
   Warnings at the beginning of this section.
   
2. Raise and safely support the vehicle.
   
3. Remove or disconnect the following:
   
   
   
   • Electrical harness connector (A) from the HO2S.
     
   • Remove the HO2 S (B) using special service tool
     J39194-B.

To Install:

CAUTION
GM uses a special anti-seize compound on the
HO2S threads. The compound consists of liquid graphite and glass
beads. The graphite tends to burn away but the glass beads remain easing sensor
removal. New or service replacement sensors have the anti-seize compound already
applied to the threads. If the sensor is removed from an exhaust component and
if for any reason the sensor is to be reinstalled the threads must have
anti-seize compound applied before installation.

1. Coat the HO2 S threads with GM P/N 5613695
   high-temperature anti-seize compound as needed.
   
2. Install the HO2 S using special service tool
   J39194-B;
   
   
   
   • Torque to 31 ft-lbs (42 Nm).
   
   
3. Connect the HO2 S electrical harness connector.
   
4. Lower the vehicle to the ground.
   

the o2 sensors are located in the exhaust system, theres one before the cat converter and one after,

Most car have twO2 sensors one in front Catalytic converter and one after.

VEHICLE SPEEDOMETER SENSOR REMOVAL/INSTALLATION

1. Disconnect the negative battery cable.
2. Drain the transmission oil.
3. Disconnect the vehicle speedometer sensor connector.
4. Remove the vehicle speedometer sensor.
5. Apply transmission oil to a new O-ring and install it on a new vehicle speedometer sensor.
6. Install the vehicle speedometer sensor. Tightening torque 69.5 - 95.4 inch lbs.
7. Connect the vehicle speedometer sensor connector.
8. Add the specified amount and type of transmission oil.
9. Connect the negative battery cable.