Hi, just looking for a little help before I go throwing my money out left and right to get rid of this code. Idle has been running a little rough bouncing up and down and I got a check engine light on. I did the diagnostic as in here > http://www.troublecodes.net/Volvo/ and found I got a 2-3-4 trouble ignition code. The site says that is a "2-3-4 Throttle switch signal missing." Would that be the TPS sensor?

 

Yes, one and the same. Before you buy a new one, check the connection. Look inside the wire boot as well as the connector on the TPS. Often one terminal or more will get bent/ corroded, etc. While you're there, check that it's adjusted properly. Move the throttle spool just a hair and it should produce a slight click just as the throttle plate begins to open. If the connections look clean and the adjustment is sound then you probably need a tps. I don't have the manual w/ me but there are voltage specs to check operability with a multi-meter.

 

Replaced with a new TPS sensor, check engine light went away. The idle is still a bit rough and I checked the codes on #6 (ignition codes) I get trouble code 2-1-4 now, "2-1-4 Ignition RPM signal erratic" what is that about? I checked all vacuum lines, doesn't seem to be any leak. I even replaced some boost clamps and cleaned up the gunky buildup in the 3 way pcv breather. What else could it be?

 

The crank sensor, located atthe rear of the engine above the flywheel/flexplate, tells the ecu and icu the rpm's. When you get that code on a non-modded car it generally refers to the sensor either failing or the connectors are bad. The sensor has a built in wire about 12 inches long w/ a typical Volvo connector on it. Although accessing the actual sensor is a chore, the connector can be easily accessed because of the slack in the wire. Just pull it up from between the cylinder head and firewall and take a good look. As I've said before, often it is merely a decade or two of corrosion and road film that causes these issues. My experience has always been that with redblock Volvo's, it is never simply one thing causing issues. In my experience, rather than one sensor failing, it is often 2 or more sensors functioning at the low side of acceptable.
My 240 sets a crank code all the time but it is a result of some rather non stock alterations. There is also a rare, outside chance the bolt holding the sensor to the bracket has vibrated loose, causing the distance between the sensor and flexplate/flywheel to fluctuate. When the crank sensor totally craps out, the engine will not run....at all.

 

Hit the nail right on the head. I really appreciate the help, swift. I checked the connection terminal and the rubber insulation was corroded and broke off exposing the wire then I noticed down near the actual sensor someone put electrical tape? I don't know what happened there but I'm ordering a new sensor ASAP. High five!

 

Glad to hear it. Sometimes fixing old Volvos is a lot like Whack-A-Mole!