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Engine light on VDC off


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I recently posted on here about my dash board failure, which is an intermittent fault, as I drive along sometimes the clock decides its 1am, the rev counter and speedo stop and the fuel guague goes to full and it all gets a bit spooky. Has been to a garage in the past but still playing up (not a water issue)

The car had this problem before I owned it so they are not linked. My brother suggested a reflux????


Anyway I also have an engine light on, someone on here suggested an O BDII from e bay - which I duly did, and insight on any of the codes below? 

Cheers :)



P0051 H02s Heater control circuit low bank 2 sensor 1 


P0643 Fuel level sensor A circuit high



manufacturers control



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Glad you got the OBDII scanner god send :) 


list of the codes here 



But P0051 common fault had it on both Scoobs :( 

What does this mean? OBD Code P0051refers to 
A P0051 DTC (diagnostic trouble code) refers to the O2 sensor (oxygen sensor) located on Bank 2 in front of the catalytic converter. There is also an oxygen sensor behind the converter which is Sensor #2. This O2 sensor #1 may also be refered to as an air/fuel ratio sensor since on some vehicles it is. It detects the amount of oxygen in the exhaust gas compared to the outside air and then vehicle's computer adjusts the air/fuel ratio going into the engine. The sensor is less effective when the exhaust gas temperature is low, so it includes a heater which is activated to help get better readings from the A/F O2 sensor. Essentially this P0051 code means that the resistance of the heater circuit is lower than normal. In most cases, that resistance level must fall below 0.8 A to trigger the DTC code. Note, this code is very similar in nature to P0031, P0032, and P0052
Symptoms Possible sumptoms of OBD code P0051
Most likely you'll not notice any symptoms other than the MIL (malfunction indicator lamp, a.k.a. the check engine light) will illuminate.
Causes Possible causes of OBD code P0051
A P0051 DTC trouble code may be caused by one or more of the following: A short in the heater circuit in the sensor A failed O2 sensor heater Wiring/connectors broken/frayed leading to sensor and/or relay Failed PCM/ECM
Possible Solutions

To fix a P0051 DTC code, you'll need to do a proper diagnosis. To do that, you'll want to inspect the wiring and connectors leading to the sensor. Also if equipped with a heater relay and fuse, you'll want to check those as well. Use a digital volt ohm meter to: check for 12 volts at the heater circuit feed (hint: unplug the sensor and check at the wiring connector to do this measurement) check the ground circuit for continuity measure the resistance of the heater circuit (done on the sensor itself) measure the resistance and voltage of the wiring Refer to a service manual for the correct specifications (volts, ohms) for your vehicle. On some Toyota vehicles this code is triggered when the resistance of the heater circuit is below 0.8 A. With that said, a common fix for this DTC is to replace the air/fuel (O2 oxygen) sensor #1 on bank 2 (the side of the engine that doesn't contain cylinder #1). Please keep in mind that OEM (original equipment) replacement sensors are recommended (from the dealer). Aftermarket sensors can be less reliable and of poorer quality (not always, but more often). There's also a chance that replacement parts for the P0051 code may also fall under a federal emissions warranty (check with your dealer to see if it's covered).


P0643 so don't have much info 


What does this mean? OBD Code P0643 refers to 
The ECM has detected that the 5 volt reference voltage is too high
Symptoms Possible symptoms of OBD code P0643
- Engine Light ON (or Service Engine Soon Warning Light)
Causes Possible causes of OBD code P0643
- ECM Short circuit condition - Shorted sensor on 5 volt circuit - Failed ECM

P1135 Only thing my check brings up is.

- Faulty O2 Sensor

- O2 Sensor harness is open or shorted
- O2 Sensor circuit poor electrical connection    




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Its possible that the 12v heater supply has shorted to the 5v reference wire due to the O2 sensor cable being frayed or trapped?

This would explain the over voltage code and possibly the other O2 related codes. JMHO

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Thank you so much for this information guys. I'm not up to the job of carrying out any further works, but I shall go to the local dealer armed to the teeth with this information and let you know the outcome.



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