96 villager Check engine light

[familyfarm]

HELP ME!! I have a 1996 Merc Villager. the Check engine light came on, it failed NJ inspection. the code first indicated the EGR valve. i replaced it, and fixed the burned out vacumm line. next the code indicated the O2 sensor. i replaced the one on the engine first. the light came right back on, so I replaced both the one on the engine manifold and the one after the converter. i tuned the engine replaced all filters, checked and repaired any exhaust leaks no matter how small and sure as day,The light came back on shortly after having the computer reset. please can anyone help solve this problem???

[tempfixit]

Originally Posted by familyfarm

HELP ME!! I have a 1996 Merc Villager. the Check engine light came on, it failed NJ inspection. the code first indicated the EGR valve. i replaced it, and fixed the burned out vacumm line. next the code indicated the O2 sensor. i replaced the one on the engine first. the light came right back on, so I replaced both the one on the engine manifold and the one after the converter. i tuned the engine replaced all filters, checked and repaired any exhaust leaks no matter how small and sure as day,The light came back on shortly after having the computer reset. please can anyone help solve this problem???

What was the code number? Shouldn't a 96 have upstream 02 sensor on each bank. Could it be you changed the wrong upstream sensor?

[familyfarm]

Originally Posted by tempfixit

What was the code number? Shouldn't a 96 have upstream 02 sensor on each bank. Could it be you changed the wrong upstream sensor?

I checked to see if there were more then one upstream O2 sensors but there is not. There is just the one (1) after the two banks join at the Y-pipe, and the (1) after the second converter

[tempfixit]

Have you checked for any new or existing codes since you changed 02 sensors?

Have you checked the wiring for the sensors and connectors?

Post the code numbers.

[familyfarm]

Originally Posted by familyfarm

I checked to see if there were more then one upstream O2 sensors but there is not. There is just the one (1) after the two banks join at the Y-pipe, and the (1) after the second converter

the code is PO135. this is sensor one bank one o2 sensor heater. I have now had it to two different shops. They performed a full diagnostic scan. they both say nothing comes up wrong it is running fine. They swear they have probed all wires and do not find any breaks. They also claim there is power to the o2 heater. The last shop had it for two weeks and could find no faults, except that the light is on and code is the same PO135.
I finally downloaded the wiring diagram from the site you posted.
When I checked the sensor I did not find any power to the o2 sensor heater. I peeled back the harness case and untaped the wires. about two inches up the wire inside the sheild I did find a broken wire. once I repaired it and reset the computer the light has stayed off. I am hoping this is the end, it has cost a small fortune in useless diagnostic fees. The worst part is one shop was a Ford Dealership. You would think they knew what to do. But what should I expect they could not fix my 93 E-150 van, after they installed a new engine.

[tempfixit]

Glad you got it fixed and thanks for posting fix. I would contact both shops and tell them what you found and see if they would reimburse you some money for fixing the problem.