I am planning to replace all four O2 sensors on my C43. The Bosch universal part# for all, before and after CAT, is 15738. My question is, are the sensors all the same. How come Bosch has separate part#'s for all four, 15088, 15090, 15092, 15094. I know that the universal needs to be spliced, but other that that, what's the difference? The universals are much cheaper.

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1991 190E 2.3 SOLD
1972 911t 2.4 owned since 4/80 300,000+ miles SOLD
1999 C43
Merlin XLM, All Ti, 17.5lbs.

Why replace the rears? They don't do anything for the cruise A/F ratio... they're only for cat efficiency.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Once you find an answer for your orig question, let me know what purpose replacing a non-faulty o2 sensor serves. Mine are original and I was thinking of doing the same, but not sure what kind of situations it would improve/remedy

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former: 83 300D, 97 C230, 93 400E

current: 08 C300 Luxury , 92 500SL

The ONLY difference ON THAT car is the length of the wires.

The actual sensor is the same foe all 4 locations.

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MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

I replaced two of the four on my wife's Expedition. I used universal ones with different part numbers and the only difference was the length of the wires. It didn't matter anyway as I used some of the wiring from the old sensor.

I was told that an O2 sensor will start to go bad slowly until a code is sent. If your O2 sensors have over 75,000 miles I bet they can be replaced and you will see results.

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'85 300SD (formerly california emissions)
'02 Jeep Grand Cherokee Limited
'04 VW Passat W8 (6spd manual) SOLD!!
'68/'69 Empi Imp body on '65 Beetle pan
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'72 Triumph T100R
'70 Yamaha R5 Rat Bike

O2 sensors are considered Maintenance items.
As they get old, they tend to move slower & slower, i.e. the transition speed between lean/rich slows down.
This can result in a reduction of fueleconomy.
I'm well aware there are people that would not consider changing these, until they see the Check Engine light on.

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2007 C 230 Sport.

my 02 sensor in the 88 260e was causing the light to come on about a mile down the road. it would then go out shortly later.

i noticed my highway mileage had dropped to 19. changed the sensor with a universal. highway mileage now back up to 24.5

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1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

If you look around, you may find sensors considerably less-expensive than the "universal." I have not tried this with 4-wire sensors, but for the single-wire type used on 380's and 560's, I used a sensor for a '90 Mustang. IIRC, the universal were like $35, and the Mustang less than $20. You just cut the end off and supply your own connectors and heat shrink.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe