Hi, i recently bought a 1999 accord ex 4 cyl 5 speed, and the previous owner put in a 2001 ULEV motor.. Im getting an engine code p0135 (pre-cat o2 sensor).. could anyone tell me if the original motor was ULEV or not? the VIN for the vehicle is 1HGCG3154XA011884

 

The original motor based on the VIN was not a ULEV. The trouble code also indicates the ECU was not for a ULEV, as that code is for a regular O2 sensor instead of an air/fuel ratio sensor used for the ULEV.

 

Thank you! that is what i thought but thanks for the confirmation. Im thinking that if i got an air fuel ratio sensor with the current ecu the light may go away? or would i have to swap the ecu for a ulev ecu? any thoughts on this?

 

If the ECU is not for the ULEV, it should only need the regular O2 sensor.

There should be no need to swap ECU, which would also be a pain due to reprogramming needed because of the Immobilizer.

The car may just have the F23A4 block from a ULEV (and maybe the cylinder head), which is essentially the same as the F23A1 (non-ULEV). The person that swapped it probably kept some of the F23A1 parts, which makes your current engine for the most part, like a F23A1.

 

Check your other thread. The big difference is the exhaust manifold, and we can hope the previous owner used the non-ULEV manifold.

There's substantial differences in the car's wiring harness too, so that makes it even more difficult than just getting a ULEV ECU.

Ive seen more than one thread where someone found a ULEV engine for cheap, so they turned it into a non-ULEV engine by swapping the exhaust manifold. That's easier than converting the CAR over to ULEV.