So throughout the years of owning my 2004 Volvo S60R I would occasionally get a "Reduced Engine Performance" warning on my dash which would result in a LHM (Limp Home Mode) situation, which was less than idea. A scan of the computer through VIDA revealed it to be due to a "Throttle Body Faulty Signal" code. In the past I had just restarted it and eventually the code would clear up, or I could clear it with VIDA, but as I was doing repairs and spending money to keep the car on the road I decided to replace the throttle body and inspect the old one.
Parts Needed:
-Bosch Throttle Body (Bosch is OE on Volvo S60) (Contactless, less prone to failure ETB)
Tools Needed:
-3/8" and 1/4" Socket Wrench
-10mm, 8mm, 7mm, T35 Torx, Sockets
-Socket Extensions or Deep Sockets
OPTIONAL: Impact Driver (I use a dewalt one, just speeds up the process)
The job is pretty easy and can be done within a few hours depending on tools and skill level. I took the time to clean all intake lines and my FMIC (front mount inter-cooler) of excess oil.
First step is to remove all air intake pieces up the the MAF. Since I have a Snabb intake and K&N air filter my process may be different, but you need to remove everything up to the MAF to access the intake hose.
Once removed you need to loosed all hose clamps on the intake lines leading from the FMIC to the throttle body. I used the sockets (7 or 8mm) to loosed all hose clamps. Once loose you can just pull the piping out. Don't forget to remove the boost sensor (located on the intake pipe near the FMIC.
You can see I had excess oil in the intake pipes, which I address later and in this post regarding the PCV and Oil Catch Can.
Remove the intake pipe.
You can see that there was some aftermarket piping with silicon tubes and stainless piping done to mine by previous owners. If you do not have a similar setup and cannot figure out how to remove your intake line I found this YouTube video to be very helpful.
Next step is to remove the charge pipe. Using a T35 Torx remove the clamp that hold it to the turbo (may be different clamps on newer models). Remove the front hose clamp connecting it to the pipe going to the FMIC and the small torx and 10mm bolts holding the charge pipe to the top of the engine.
Next loosen the hose clamp holding the plastic intake pipe to the throttle body.
Then wiggle the plastic intake pipe off of the throttle body.
Next use a 10mm socket on a short extension or a 3/8" drive deep socket to remove the four 10mm bolts that hold the throttle body to the intake manifold.
Remove the throttle body. Mine came off really easily, but prying may be necessary. Be careful not to mare the surface where the seal/gasket is located.
To reinstall, just repeat the process using a new gasket. I did notice that when I installed the Fel-Pro gasket the bolt holes didn't line up perfectly, but that really didn't effect it much.
Reinstalled underneath the intake manifold:
Inspection old vs new:
The old one appeared to have excess oil, but not actually signs of failure that I could detect.
Old Throttle Body Internals:
There was defiantly an excess of oil inside the throttle body. Its not clear weather removing the oil and cleaning the inside of the TB would fix my issue as I did not get to retest my old one, however there are four very small metal contacts that I worry loose contact over time which would throw the code. You could potentially straighten them out, but as the new part is only $200ish it seemed worth it for me to replace it.
You can see the metal brush contacts are slightly off center, but they are easily bendable and can be re-aligned with a needle nose pliers.
Here is the circuit board that the brushes contact, no wear/damage there:
Cleaning Excess Oil in Intake Lines and Front Mount Inter-cooler:
Since I had a lot of oil in my intake and FMIC I wanted to clean it out before reinstalling a new throttle body. For the charge pipe and intake lines I used Simple Green De-greaser, an air gun, and paper towels to clean the oil out. Rinsed them with water and let them dry.
The FMIC is harder to clean. In order to get the oil out I sprayed simple green in both sides and let it sit. I then attached a shop vacuum to one side and while running the vacuum and sealing around the vacuum's attachment to the intake I sprayed simple green into the other opening. This sucked the oil and simple green through the inter-cooler and hopefully removed a lot of the oil. I used a blow gun to help push the oil/simple green through. I let the car sit overnight also with the hoses removed to let it dry out. So far so good!
The excess oil in the intake was of concern also. In order to deal with the excess oil the PCV needs to be address, but as mine was replaced a few years ago and passes the glove test (glove on oil intake does not inflate at idle) I began to do some research. It appears that a lot of S60R owners have had this issue also if they begin to modify and many have gone to Oil Catch Cans which I will be installing shortly with a full write up:
UPDATE (Jan 2019): So the code (throttle body faulty signal) has returned putting my car into reduced performance mode again. Doing further research it looks like it may be due to a bad connector. Luckily Volvo sells the harness for about $40, but requires a ECU removal tool to access the connectors. I am going to attempt to repair the connections first then replace the harness if the code returns and will update.
For the repair I removed the connector and cleaned it with an electrical connector spray and then blew it out with a hose and inspected. It appears normal and the clips are both intake.
I also decided it was a good idea to check all ground on the engine as well. I cleaned all the ground with a wire wheel attached to a drill (I bought this set a while ago and worked well). I also added an additional engine-chassis ground, just in case.
When I removed the stock chassis to engine ground I found that it had snapped. Hard to tell if I did it when removing it or not, but either way I relocated the ground to the strut tower. Because this was painted I had to grind it down to bare metal.
So far the car is running fine without codes for the throttle body. I will report back with updates if this fix works. If not, the next step is to replace the connected with below Volvo part, however as the idea of tapping into the ECU terminals is somewhat daunting I plan to just cut and splice in the new connector.
SIDE NOTE: I also learned that if you are dealing with the "reduced engine performance" limp mode that a cheap scanner will clear it, even if there is no check engine light on. I realized this when I was in limp mode from a throttle body issue and my buddy scanned my car, showing no code stored (on a cheap scanner), but then he cleared the codes anyway and my car instantly went out of limp mode. Something to think about as it takes a while for VIDA to boot up for me and I dont want to carry my laptop everywhere I go. This is the scanner I use that works great: ANCEL AD410 Enhanced OBD II Scanner
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