Autodata’s Technical Team share their fixes to common problems raised through Autodata’s technical helpline, available to all UK customers.
Smart Fortwo – Engine malfunction indicator lamp (MIL) illuminated.
We have previously replaced heated oxygen sensor (HO2S) 2 on a customer’s Smart Fortwo 1.0. The vehicle has returned with the engine malfunction indicator lamp (MIL) illuminated and the same trouble codes stored (P0136, P0137, P0138, P0139, P0141, P2271). We discovered the heated oxygen sensor (HO2S) wiring broken again. Is there a known fault with the wiring for the heated oxygen sensor (HO2S)?
This repeated breaking of the HO2S wiring harness is known to us and affects turbocharged Fortwo (451) 1.0 models, VIN→K418899. The fault is caused by engine movement coupled with an acute angle of the HO2S wiring harness. Fit a new HO2S. Fit a protective cover to the HO2S wiring harness (see Fig 2.1). Then erase the trouble codes.