smoothaseggs

hello evryone. i acquired a 1989 300e with 200k on the odo. it actually runs well however, the engine light recently came on and i need to get it smogged. i have no service history for the car so not sure where to start. maybe o2 sensor or ? any advice would help. trying to get it straightened out so the kids have a safe car to drive around in. i had heard that you could possibly use a o2 sensor from a mustang? what year? v6 or v8? is it direct fit or modified? thanks

deanyel

You have an 89 with a check engine light? It actually says "check engine"? If so it must be a CA version, in which case you should be able to read the fault codes on the diagnostic connector in the engine compartment. A Bosch universal O2 sensor for your car is only $57 at AutohausAZ - hardly worth messing with a Mustang sensor. The OE plug version is only $82.

smoothaseggs

it is a ca car. i thought of the mustang o2 sensor cause both the bosch universal and the mustang bosch needs to be spliced. what is the procedure for reading the fault codes. i'm guessing it is a series of beeps.

ohlord

box up by the battery.
You read the blinks and since your model only had about 5 inputs for cel at those miles it most likely is the 02 sensor.
harness to unplug it is under the pass floor carpet.
Enjoy

deanyel

Flashes rather than beeps. Can you take a picture of the area around your battery, or tell us what diagnostic connector you have?

smoothaseggs

i looked near the battery today and i found the little black box. i pulled the lid to see the numbers and the sockets near the numbers. with the car running the red led is on constantly. i turned the car off then moved the key to the on position. i then pushed the button for approx 1-3 seconds and the the light flashed 4 times then i think it flashed once then glowed steadily. i tried pushing again and no more flashing. did i have the correct procedure. thanks for the help

deanyel

With the ignition on, warning lights on, car not running, hold the button down for 3 seconds, LED should go on, release button, LED should go off, count the number of flashes that follows, repeat until the same code comes up again. To delete codes, within 20 seconds of reading the code, hold button down for 8 seconds, again LED should go on, release button, LED should go off, turn ignition off for several seconds between each code deletion.

Code 4 is air flow sensor position indicator. Code 5 is oxygen sensor.

smoothaseggs

for the code 4 fault is it a buy a replacement part type fault?

deanyel

That's probably referring to the potentiometer that attaches on the side of the air flow meter. It was never available as a separate part from Mercedes but was available through Bosch for about $40. But then they discontinued it and you had the buy the whole air flow meter for about a thousand. But I noticed it recently came back - as a $200 part. Europartsdirect.com has them. But it's too soon to start buying parts - you need to delete the code, drive the car, read the codes a few times - in other words make it come back, and make sure they aren't any more codes.

smoothaseggs

your right, i will clear the code tomorrow and recheck to see if the same pops back up. thanks for your help

ohlord

you said it blinked 5 times?
Check again like above so you can order the right part.
O2 sensor is more common and far cheaper.

smoothaseggs

checked the flashes again and it definiteley is/was 4 flashes. i went ahead an cleared it and there were no other codes. i have only driven it a little bit but has not popped back up. gonna drive it more to see if anything comes up. any way to clean the air flow pot or whatever is setting off the code 4

deanyel

Given the price of the part that's probably what I would do, take the whole thing off and clean it with throttle body cleaner and electrical contact cleaner, not that it's likely to work but it might and it doesn't cost anything. You can always buy the part later.