QuestionQUESTION: Hi Roland:
Today, when I start the Van, the service engine soon light turn on, I check the code using the ignition key, the service engine light flashes and the number code it gave me is, 122155. Can you gently tell me, what it means the fault code number and how I erase it? Thank you.
ANSWER: Hi Sergio,
The only important code is 21 which means that an oxygen sensor is not changing its voltage value as would be expected, suggesting that it is no good. Probably there is one* on the rear side exhaust manifold. It looks like a spark plug. I would check the wires (4) to see if any are broken as they are fragile. If not, then I can give you the wire colors and you can check to see that it is not changing voltage and is therefor shot. Soak the threads overnight with penetrating oil and then gently rock back and forth to loosen it and remove without stripping the threads on the manifold. Use anti-lock thread grease on the new threads (it comes with this already,usually) and tighten it to about the same as a spark plug, 20 foot-lbs.
You can erase all codes except 12 by disconnecting the battery for a minute.
Roland
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The 12 code means the battery was disconnected recently so that one always 'returns'. The 55 means 'end of fault code readout'.
*There might be another oxygen sensor, after the catalytic converter (downstream), but if its wiring is not damaged it is much less likely to be worn out than the one on the exhaust manifold proper. But take a look for it, under the van on the exhaust pipe.
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QUESTION: Roland:
Thank you very much for the information. Today I follow you instructions, I can't reach the oxygen sensor on the rear side exhaust manifold or the wires, I can only saw the wires, they apparently look fine. The second oxygen sensor is easy to check, the wires are ok.
AnswerHi Sergio,
There is a more specific code readout you can get which will tell you which sensor is bad and why. It is done with a code reader that plugs into the socket that is under the dash by the steering column. If you have an Autozone parts store near you they will do the readout for free and if not, ask at any other such nationwide parts stores how much they charge to do a code readout. A small independent mechanic will probably do it for $40 or less. Ask for the 4-digit code number(s) that it shows, and what it means, and the cost of repair. Then get back to me and we will compare to the manual and we should then know which sensor needs to be replaced based upon the code number which is specific to the sensor that is bad. If you have to replace the exhaust manifold sensor you may find it easier to access from underneath. But let's find out first what is the number. It will also have a "P" as a prefix but all the codes do also, so the 4-digits are what we need to know.
Roland
Thank you very much for the rating and most of all for the 'nomination'. You may do the same again for this answer if you would be so kind.
