After years of having todriving junk cars (business failure,child support, etc), i just bought a '98 sl500 and was so happy, seemed to have only minor probs-check engine lightand top would not go down(118k miles). Took it to a MB shop down the street from me (not dealer) & this is what he says:
Checked engine with hand held tester. found following code: P0410-secondary air injection. checked air injection system. found no power to air pump from fuel injection computer. tested air pump manually, pump runs but air not circulating through cylinder head ports. possible needs fuel injection computer. will also need cylinder heads removed and sent out for sublet repair to remove carbon buildup, Labor=$2200.00 plus parts
Check power top/roll bar system with hand held tester. found following codes in roll bar system: 121-cover locked switch right, 97-left window activation, 124-left door actuator right front trunk lid lock, 80-hydraulic unit fault, 96-right window actuation, 117-bow locked switch, 120-soft topopen switch, 51-hydraulic unit temp, and 52-hydraulic unit. unable to communicate with soft top computer. vehicle will need hydraulic pump unit and soft top control unit replaced and possiblyother repairs in order to operate top. Hydraulic pump $2604.00 plus labor. soft top control unit $1526.00 plus labor.
The car really runs out STRONGin the street. i can't possibly afford these types of repairs, so was just wondering, hoping and yes even praying that maybe some type of computer re-set might be the answer. i can't get emissions, tag, insurance with the check engine light on.
Could really use some knowledgeable advise, i.e.-junk it, build a shrine to what could have been or how rorepair it for about 2K (which is what i can come up with). Thanks

 

First of all, if you are in the US,if you bought your car from a business, depending on your state, it is illegal to sell a car with a faulty emmisions systems, ie Check engine light on,the business is responsible for the repair, and the law supercedes any "as is" statement. Check with a local licensed attorney in your state.

Next, if you bought from an individual whos occupation is NOT primarilythe sales of cars, or from an auction, you will have to fix the car. But get the mechanics to inspect the wire harness before you start changing-out $1000 computers. They recently went all through my car replacing stuff, and eventually discovered that damaged wires were the problem. And its not their fault, they're not deliberately trying to cheat you or waste your time; apparently the troubleshooting routine assumes that nothing can happen to the wiring. My case.

Also I am hearing that peers are going to the junkyard and grabbing all the computers off carsfor under $300.
They then use the computers for testing, troubleshooting, swapping, spares, repairs etc. How good are you at plugging stuff in?

Blue

 

igotcha, thanks blue
i live in atlanta metro, could circumvent emissions with bogus address, but don't really want to go that route unless i have to. bought it from dealer in non emissions county & don't know legal technicalities yet.bottom line-I've fallen love with the car & really want to keep it and drive it if poss. i can prob plug-in, but only under supervision (explicit directions). have taken stuff apart before and created a worse disaster than i had (humpty dumpty like situation), but would be willing to try it on this. i just can't help but believe (gut feeling)that it's not as major as has been indicated, like you said, it's just symptomatic of something else. thnx...jim

 

Oh dear!

The diagnosis given is entirely feasible and quite possible if somebody has intentionally sold you a dud.

However it is unlikely that two major ECU problems exist unless this has been the situation for some time since having two systems go so bad at the same time is extremely unlikely unless there is a common cause. e.g. chewed wiring / water damage etc.

However since the faults are potentially very costly I would start by getting an MB dealer to rescan the diagnostic codes and advise the codes found ensuring that you do not give authority to proceed with repair. Don't advise that this is a second opinion etc. Act dumb. If this part of the "story" stacks up then it appears that you have a big problem.

The CEL has to be your most important problem since this impacts your smog test.

It is indeed strange that everything else on the engine/trans computer appears fine except the secondary air injection pump which is said to be OK but no signal from ECU.
In addition when the pump is connected direct to power it runs but airways are said to be blocked. As I say feasible but a little surprising. Not that easy for an owner to check this diagnosis out...by intent or otherwise. I do not subscribe to all garages being rip offs but I certainly would check this out discreetly just in case.

OK IF the diagnosis is confirmed I would inspect the wiring and integrity/condition of connectors between components on the engine and trans harness to the black box at the back of the engine compartment. Tedious but basically straight forward. If you are not techy/DIY'er suggest you get a friend who is to do this for you, If no problem found I would then move on to confirming that the pump runs (very simple) and that the exit airway Is or Is Not blocked by blowing through it.

At this point I am not sure what controls the Secondary Air Injection Pump power. A signal will come from the ECU (computer) but this signal may operate a relay control for power and likelwise there is likely to be a fuse in the circuit. Relays and fuses are inexpensive.

Good luck. I'm feel this is going to turn out OK. Other members may well be able to confirm the relay/fuse configuration and location

Stuart

 

Thanks Stuart for your time, interest & direction. Though not a Tech. myself, I did question how so much stuff could go sobad so quickly in an otherwise ok car. My 1st question to the Tech doing the diagnosis was do you think that it is water damage, but he wouldn't commit toan answer, said "I don't know, it could be!". I did look for that, but car is out of Miami and i saw no obvious signs and what i did see, i attributed to the coastal environment.
Maybe now, with the suggestions from you and Blue (see above), I can at least begin to troubleshoot the probs. instead of replacing everything. I drove the car Sat. night (i'm legal until 12/24/07-30 days from purchase)& what a blast it is to drive. I had originally thought that a major tune up would correct probs, but the tech said that thecomputer says that it's not due to be serviced for another 6,900 miles. If you or other members think of anything else, it would be greatly appreciated.

 

So you have only just bought this car. Correct?
Privately I guess. What does the previous owner say (if anything)!
Basically you bought the car with the light ON but thought that it just needed a service.
What service history comes with the car (if any). Where / when has it been serviced since new. How many owners. When etc. this will give a clearer picture of what might be wrong.

What have you noticed that you put down to coastal location?

98 / 118k miles SHOULD be nothing to a Merc!
Maybe start at the beginning with what model the car is etc.

Are you going to get a second opinion/code read.
Come back and we will try to help further.

I do not believe that it will be the computer if everything else on the engine/trans is fine.
You can get the engine codes read at many garages for free in the States apparently. 5 min job tops.
We want the codes not not what the garage thinks is wrong but it is still helpful to see what they say.

Stuart.