O2 Sensor, Environmental Blower Issue, Shop Manual

Howdy folks,

I'm posting this question on behalf of my dad who is still very much afraid of his computer. He's got a 1998 S70GLT. I've attempted to Google for any obvious answers to these questions or for an S70 FAQ but couldn't find anything obviously relevant. Three questions:

  1. My dad's fond of doing his own repairs, but has found the Chilton shop manuals not specific and helpful enough. Are there any other recommendations for reasonably-priced shop manuals?

  1. Recently, a mechanic inspected some of the output from the on-board systems and suggested his fuel's running a little rich and he might need to replace his O2 sensor. Apparently, however, there are actually two of them. The car has about 147K miles on it. Should he replace both O2 sensors as a matter of preventive maintenace or just one? If just one, which?

And the fun one:

  1. Occasionally, when he starts the car up, the environmental system starts working for less than a second, then completely stops and both the 'recirculate' button light (which is orange) and the 'off' button light (which is also orange) start blinking. This *NEVER* happens in the morning when he first starts the car, and it *NEVER* happens mid-drive -- only when he starts the car up (or just turns the key to the 'on' position). Turning the car off and on again, several times, often clears this, but sometimes not. Any ideas?

Thanks for any suggestions anyone may be able to come up with,

-roy

Reply to
royrapoport
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From 1996 onward, the only manual supplied by Volvo is the electrical diagrams. Everything else is available on the web, via subscription, or some extremely expensive DVD's.

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The OBD fault codes were readable vian an underhood panel and documented in the service manuals on 94 and 95 models. WIth later models, the only way to find out what sensor turned on the light is via a $50.00 trip to the dealer, or possible a generic scantool, assuming the "public" codes can differentiate a front from a rear sensor.

Another $50.00 trip to the dealer. The codes for non-emissions-releaed faults are not available to owners any more, although you can find some of them online:

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occasionally get the climagte control blinks on my 94, and the codeis for one of the cabin temp sensors. The ones near the driver's andpassenger's heads have tiny fans to draw the air through them. Ifthese fans are clogged and sticking, this will generate a code. Trade it in for a 95. I like to work on my cars too, but Volvo has made it impossible for owners to maintain their new models, so I won't be buying another one.

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Reply to
Doug Warner

I wouldn't do anything without more detail than this. Was the check engine light on? If not, I wouldn't do anything. If so, what you do depends on which code(s) is/are stored. Generally the front sensor is the one that goes bad first, and is the one that has the most effect on the mixture. The rear one is just there to check both the front sensor and the catalytic convertor.

This will have set a code for the climate control, which will only be readable with code readers with Volvo specific applications. However, since the fan is shutting down, a good guess is the fan motor. As the bearings seize up, the motor starts to draw more current for a given applied voltage. The climate computer monitors this, and turns the fan off to protect the speed control circuit. Once again it would be better to have the code read to make sure, rather than guessing.

Reply to
Mike F

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