Fault Codes on 1993 W124 280 (104 engine)

[wdbmerc]

Hi,

I had a recent problem with intermittent poor running on my 1993 E280 with a 104 engine....replaced OVP and Fuel Pump relay as suggested on Forum. All good for three months until last Firday a frosty morning.... poor running again on start up - once warmed up ok .... then went again whilst engine warm.....then rectified itself and no problems since!!!

Checked the OBD fault codes ---- on Socket 8 showed flash codes 9, 11, 22 cleared these then showed 2,9,11 ....cleared again and 9,11 and 22 keep repeating. Unsure what the fix should be from here any suggestions please??

 

[abecketts]

Might be the wiring loom, read up on the "sticky" about w124 wiring looms

 

[GP801]

Coil pack, wiring loom and ECU are the likely culprits. We had a similar issue 3-4 years back. Dodgy coil pack had fried the ECU. I sincerely hope its not the ECU as its very expensive to replace. Don't ignore it because if it is a coil pack or loom issue it could end up killing the ECU.

 

[wdbmerc]

Thanks for the advice ..... How will I know if the ecu has fried????

 

[GP801]

Thanks for the advice ..... How will I know if the ecu has fried????

Not entirely sure. Ours had an intermittent misfire as if it dropped a couple of cylinders. Like yours it had new relays, HT leads, coil packs and the problem inevitably returned. I think they worked it out from the diagnostic port/computer readings but only whilst it was actually misfiring. It got so bad at one point it was hard to move above walking pace.

 

[kingdave]

I had similar problems with my E280 recently, it ended up being the lamda/o2 sensor. Your best bet might be to find an indie specialist who's seen dozens of these engines before and will know where to look to find the problem.

 

[kth286]

Hi,

I had a recent problem with intermittent poor running on my 1993 E280 with a 104 engine....replaced OVP and Fuel Pump relay as suggested on Forum. All good for three months until last Firday a frosty morning.... poor running again on start up - once warmed up ok .... then went again whilst engine warm.....then rectified itself and no problems since!!!

Checked the OBD fault codes ---- on Socket 8 showed flash codes 9, 11, 22 cleared these then showed 2,9,11 ....cleared again and 9,11 and 22 keep repeating. Unsure what the fix should be from here any suggestions please??

9 & 11 are both Oxygen sensor (lambda) problems. 11 is the heater inside it not working.

As both are showing perhaps the cable is at fault at the plug under carpet on floor under front seat.

If cable is OK I would change sensor as they become sluggish anyway at 100k miles.

The 22 code is for coil T1 (front coil of three).

It is over cylinder 2 and the lead goes to cylinder 5.

I suspect it is the lead for cylinder 5. Actually the connector at end of lead down to spark plug 5 (about £12 from merc dealer).

Those connectors break down from heat (it's the 2k ohm wire inside).